diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index ab78b11b158..3623df5bd94 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -7264,9 +7264,9 @@ aarch64_vfp_is_call_candidate (cumulative_args_t pcum_v, machine_mode mode,
 /* Given MODE and TYPE of a function argument, return the alignment in
    bits.  The idea is to suppress any stronger alignment requested by
    the user and opt for the natural alignment (specified in AAPCS64 \S
-   4.1).  ABI_BREAK is set to true if the alignment was incorrectly
-   calculated in versions of GCC prior to GCC-9.  This is a helper
-   function for local use only.  */
+   4.1).  ABI_BREAK is set to the old alignment if the alignment was
+   incorrectly calculated in versions of GCC prior to GCC-9.  This is
+   a helper function for local use only.  */
 
 static unsigned int
 aarch64_function_arg_alignment (machine_mode mode, const_tree type,
@@ -7342,11 +7342,24 @@ aarch64_layout_arg (cumulative_args_t pcum_v, const function_arg_info &arg)
   if (pcum->aapcs_arg_processed)
     return;
 
+  bool warn_pcs_change
+    = (warn_psabi
+       && !pcum->silent_p
+       && (currently_expanding_function_start
+	   || currently_expanding_gimple_stmt));
+
+  unsigned int alignment
+    = aarch64_function_arg_alignment (mode, type, &abi_break);
+  gcc_assert (!alignment || abi_break < alignment);
+
   pcum->aapcs_arg_processed = true;
 
   pure_scalable_type_info pst_info;
   if (type && pst_info.analyze_registers (type))
     {
+      /* aarch64_function_arg_alignment has never had an effect on
+	 this case.  */
+
       /* The PCS says that it is invalid to pass an SVE value to an
 	 unprototyped function.  There is no ABI-defined location we
 	 can return in this case, so we have no real choice but to raise
@@ -7417,6 +7430,8 @@ aarch64_layout_arg (cumulative_args_t pcum_v, const function_arg_info &arg)
      and homogenous short-vector aggregates (HVA).  */
   if (allocate_nvrn)
     {
+      /* aarch64_function_arg_alignment has never had an effect on
+	 this case.  */
       if (!pcum->silent_p && !TARGET_FLOAT)
 	aarch64_err_no_fpadvsimd (mode);
 
@@ -7481,7 +7496,7 @@ aarch64_layout_arg (cumulative_args_t pcum_v, const function_arg_info &arg)
 	  && (aarch64_function_arg_alignment (mode, type, &abi_break)
 	      == 16 * BITS_PER_UNIT))
 	{
-	  if (abi_break && warn_psabi && currently_expanding_gimple_stmt)
+	  if (warn_pcs_change && abi_break)
 	    inform (input_location, "parameter passing for argument of type "
 		    "%qT changed in GCC 9.1", type);
 	  ++ncrn;
@@ -7544,7 +7559,7 @@ on_stack:
       int new_size = ROUND_UP (pcum->aapcs_stack_size, 16 / UNITS_PER_WORD);
       if (pcum->aapcs_stack_size != new_size)
 	{
-	  if (abi_break && warn_psabi && currently_expanding_gimple_stmt)
+	  if (warn_pcs_change && abi_break)
 	    inform (input_location, "parameter passing for argument of type "
 		    "%qT changed in GCC 9.1", type);
 	  pcum->aapcs_stack_size = new_size;
@@ -7664,14 +7679,13 @@ aarch64_function_arg_boundary (machine_mode mode, const_tree type)
   unsigned int alignment = aarch64_function_arg_alignment (mode, type,
 							   &abi_break);
   alignment = MIN (MAX (alignment, PARM_BOUNDARY), STACK_BOUNDARY);
-  if (abi_break & warn_psabi)
+  if (abi_break && warn_psabi)
     {
       abi_break = MIN (MAX (abi_break, PARM_BOUNDARY), STACK_BOUNDARY);
       if (alignment != abi_break)
 	inform (input_location, "parameter passing for argument of type "
 		"%qT changed in GCC 9.1", type);
     }
-
   return alignment;
 }
 
diff --git a/gcc/function.cc b/gcc/function.cc
index d5ed51a6a66..b037e7de31a 100644
--- a/gcc/function.cc
+++ b/gcc/function.cc
@@ -5049,9 +5049,12 @@ stack_protect_epilogue (void)
    PARMS_HAVE_CLEANUPS is nonzero if there are cleanups associated with
    the function's parameters, which must be run at any return statement.  */
 
+bool currently_expanding_function_start;
 void
 expand_function_start (tree subr)
 {
+  currently_expanding_function_start = true;
+
   /* Make sure volatile mem refs aren't considered
      valid operands of arithmetic insns.  */
   init_recog_no_volatile ();
@@ -5244,6 +5247,8 @@ expand_function_start (tree subr)
   /* If we are doing generic stack checking, the probe should go here.  */
   if (flag_stack_check == GENERIC_STACK_CHECK)
     stack_check_probe_note = emit_note (NOTE_INSN_DELETED);
+
+  currently_expanding_function_start = false;
 }
 
 void
diff --git a/gcc/function.h b/gcc/function.h
index 098613766be..19abc5e7e6e 100644
--- a/gcc/function.h
+++ b/gcc/function.h
@@ -719,4 +719,6 @@ extern const char *current_function_name (void);
 
 extern void used_types_insert (tree);
 
+extern bool currently_expanding_function_start;
+
 #endif  /* GCC_FUNCTION_H */
diff --git a/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align16-O2-extra.C b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align16-O2-extra.C
new file mode 100644
index 00000000000..c45be832d5b
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align16-O2-extra.C
@@ -0,0 +1,86 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps -Wno-narrowing" } */
+
+#define ALIGN 16
+//#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, f16, f16p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 12 { xfail *-*-* } } } */
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} "" { target *-*-* } 47 } f1 */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} "" { target *-*-* } 48 } f2 */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} "" { target *-*-* } 49 } f4 */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} "" { target *-*-* } 50 } f8 */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 53 }  fp */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Bitfield call argument in registers.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} ""  { target *-*-* } 60 } g1 */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} ""  { target *-*-* } 61 } g2 */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} ""  { target *-*-* } 62 } g4 */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} ""  { target *-*-* } 63 } g8 */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 66 }  gp */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 67 } g1p */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 68 } g2p */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 69 } g4p */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 70 } g8p */
+
+
+/* Bitfield parameter in stack.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} "" { target *-*-* } 74 } f1_stack */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} "" { target *-*-* } 75 } f2_stack */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} "" { target *-*-* } 76 } f4_stack */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} "" { target *-*-* } 77 } f8_stack */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 80 }  fp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* Bitfield call argument in stack.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} ""  { target *-*-* } 87 } g1_stack */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} ""  { target *-*-* } 88 } g2_stack */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} ""  { target *-*-* } 89 } g4_stack */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} ""  { target *-*-* } 90 } g8_stack */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 93 }  gp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* Bitfield parameter in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} "" { target *-*-* } 101 } f1_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} "" { target *-*-* } 102 } f2_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} "" { target *-*-* } 103 } f4_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} "" { target *-*-* } 104 } f8_stdarg */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 107 }  fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 111 } f8p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} ""  { target *-*-* } 114 } g1_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} ""  { target *-*-* } 115 } g2_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} ""  { target *-*-* } 116 } g4_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} ""  { target *-*-* } 117 } g8_stdarg */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 120 }  gp_stdarg */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 121 } g1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 122 } g2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 123 } g4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 124 } g8p_stdarg */
diff --git a/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align16-O2.C b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align16-O2.C
new file mode 100644
index 00000000000..61d12ec22eb
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align16-O2.C
@@ -0,0 +1,87 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps -Wno-narrowing" } */
+
+#define ALIGN 16
+#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, f16, f16p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 12 { xfail *-*-* } } } */
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} "" { target *-*-* } 47 } f1 */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} "" { target *-*-* } 48 } f2 */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} "" { target *-*-* } 49 } f4 */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} "" { target *-*-* } 50 } f8 */
+
+/* No change in parameter passing in GCC 9.1 for lines 53-57 (fp, f1p, f2p,
+   f4p, f8p) (because the argument fits in a single register).  Should not
+   warn, but aarch64_function_arg_boundary would need to take the argument size
+   into account as well as whether it's passed via registers or the stack.  */
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 53 }  fp */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Bitfield call argument in registers.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} ""  { target *-*-* } 60 } g1 */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} ""  { target *-*-* } 61 } g2 */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} ""  { target *-*-* } 62 } g4 */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} ""  { target *-*-* } 63 } g8 */
+
+/* No change in parameter passing in GCC 9.1 for lines 66-70 (gp, g1p, g2p,
+   g4p, g8p), no warning expected.  */
+
+
+/* Bitfield parameter in stack.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} "" { target *-*-* } 74 } f1_stack */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} "" { target *-*-* } 75 } f2_stack */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} "" { target *-*-* } 76 } f4_stack */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} "" { target *-*-* } 77 } f8_stack */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 80 }  fp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* Bitfield call argument in stack.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} ""  { target *-*-* } 87 } g1_stack */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} ""  { target *-*-* } 88 } g2_stack */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} ""  { target *-*-* } 89 } g4_stack */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} ""  { target *-*-* } 90 } g8_stack */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 93 }  gp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* Bitfield parameter in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} "" { target *-*-* } 101 } f1_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} "" { target *-*-* } 102 } f2_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} "" { target *-*-* } 103 } f4_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} "" { target *-*-* } 104 } f8_stdarg */
+
+/* Parameter passing for these should not have changed in GCC 9.1 (PR 105549).
+   Fortunately we warn. Note the discrepancy with lines 120-124 below: we warn
+   in the callee, but not in the caller.  */
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1} "" { target *-*-* } 107 }  fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 111 } f8p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'S1' changed in GCC 9.1} ""  { target *-*-* } 114 } g1_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2' changed in GCC 9.1} ""  { target *-*-* } 115 } g2_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4' changed in GCC 9.1} ""  { target *-*-* } 116 } g4_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8' changed in GCC 9.1} ""  { target *-*-* } 117 } g8_stdarg */
+
+/* No change in parameter passing in GCC 9.1 for lines 120-124 (gp_stdarg
+   g1p_stdarg, g2p_stdarg, g4p_stdarg, g8p_stdarg), no warning expected.  */
diff --git a/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align32-O2-extra.C b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align32-O2-extra.C
new file mode 100644
index 00000000000..04b183af697
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align32-O2-extra.C
@@ -0,0 +1,119 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps -Wno-narrowing" } */
+
+#define ALIGN 32
+//#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+
+/* In f1, f2, f4, f8, f16 (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[x1\\\]" 10 } } */
+
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* In f16p (and stdarg version):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 2 { xfail *-*-* } } } */
+
+/* In f1_stack, f2_stack, f4_stack, f8_stack, f16_stack, f8p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx\[0-9\]+, \\\[sp, 8\\\]" 6 { xfail *-*-* } } } */
+
+/* In fp_stack, f1p_stack:  */
+/* { dg-final { scan-assembler-times "ldrb\tw0, \\\[sp, 8\\\]" 2 { xfail *-*-* } } } */
+
+/* In f2p_stack:  */
+/* { dg-final { scan-assembler-times "ldrh\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f4p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f16p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[sp, 16\\\]" 1 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 47-51 (f1, f2, f4, f8, f16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 53-57 (fp, f1p, f2p,
+   f4p, f8p) because the argument fits in a single register.  Should not warn,
+   but aarch64_function_arg_boundary would need to take the argument size into
+   account as well as whether it's passed via registers or the stack.  */
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}  "" { target *-*-* } 53 } fp */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Changed in GCC 9.1, but we fail to emit a warning since GCC 11 (was OK with GCC 9).  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { xfail *-*-* } 58 } f16p */
+
+
+/* Bitfield call argument in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 60-64 (g1, g2, g4, g8, g16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 66-70 (gp, g1p, g2p,
+   g4p, g8p), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { xfail *-*-* } 71 } g16p */
+
+
+/* Bitfield parameter in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 74-78 (f1_stack,
+   f2_stack, f4_stack, f8_stack, f16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* Changed in GCC 9.1.  */
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}  "" { target *-*-* } 80 } fp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* No change in parameter passing in GCC 9.1 for line 85 (f16p_stack) because
+   the overall alignment is >= 16.  No warning expected.  */
+
+
+/* Bitfield call argument in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 87-91 (g1_stack,
+   g2_stack, g4_stack, g8_stack, g16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}  "" { target *-*-* } 93 } gp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* No change in parameter passing in GCC 9.1 for line 98 (g16p_stack).  No
+   warning expected.  */
+
+
+/* Bitfield parameter in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 101-105 (f1_stdarg,
+   f2_stdarg, f4_stdarg, f8_stdarg, f16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}   "" { target *-*-* } 107 } fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1}  "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1}  "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1}  "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1}  "" { target *-*-* } 111 } f8p_stdarg */
+
+/* No change in parameter passing in GCC 9.1 for line 112 (f16p_stdarg).
+   Should not warn.  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { target *-*-* } 112 } f16p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 114-118 (g1_stdarg,
+   g2_stdarg, g4_stdarg, g8_stdarg, g16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 120-124 (gp_stdarg,
+   g1p_stdarg, g2p_stdarg, g4p_stdarg, g8p_stdarg), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { xfail *-*-* } 125 } g16p_stdarg */
diff --git a/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align32-O2.C b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align32-O2.C
new file mode 100644
index 00000000000..cdb5b4df774
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align32-O2.C
@@ -0,0 +1,119 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps -Wno-narrowing" } */
+
+#define ALIGN 32
+#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, f16 (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[x1\\\]" 10 } } */
+
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* In f16p (and stdarg version):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 2 { xfail *-*-* } } } */
+
+/* In f1_stack, f2_stack, f4_stack, f8_stack, f16_stack, f8p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx\[0-9\]+, \\\[sp, 8\\\]" 6 { xfail *-*-* } } } */
+
+/* In fp_stack, f1p_stack:  */
+/* { dg-final { scan-assembler-times "ldrb\tw0, \\\[sp, 8\\\]" 2 { xfail *-*-* } } } */
+
+/* In f2p_stack:  */
+/* { dg-final { scan-assembler-times "ldrh\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f4p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f16p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[sp, 16\\\]" 1 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 47-51 (f1, f2, f4, f8, f16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 53-57 (fp, f1p, f2p,
+   f4p, f8p) because the argument fits in a single register.  Should not warn,
+   but aarch64_function_arg_boundary would need to take the argument size into
+   account as well as whether it's passed via registers or the stack.  */
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}  "" { target *-*-* } 53 } fp */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Changed in GCC 9.1, but we fail to emit a warning since GCC 11 (was OK with GCC 9).  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { xfail *-*-* } 58 } f16p */
+
+
+/* Bitfield call argument in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 60-64 (g1, g2, g4, g8, g16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 66-70 (gp, g1p, g2p,
+   g4p, g8p), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { xfail *-*-* } 71 } g16p */
+
+
+/* Bitfield parameter in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 74-78 (f1_stack,
+   f2_stack, f4_stack, f8_stack, f16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}  "" { target *-*-* } 80 } fp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* No change in parameter passing in GCC 9.1 for line 85 (f16p_stack) because
+   the overall alignment is >= 16.  No warning expected.  */
+
+/* Bitfield call argument in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 87-91 (g1_stack,
+   g2_stack, g4_stack, g8_stack, g16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}  "" { target *-*-* } 93 } gp_stack */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* No change in parameter passing in GCC 9.1 for line 98 (g16p_stack).  No
+   warning expected.  */
+
+
+/* Bitfield parameter in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 101-105 (f1_stdarg,
+   f2_stdarg, f4_stdarg, f8_stdarg, f16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* Parameter passing for these should not have changed in GCC 9.1 (PR 105549).
+   Fortunately we warn. Note the discrepancy with lines 120-124 below: we warn
+   in the callee, but not in the caller.  */
+/* { dg-note {parameter passing for argument of type 'Sp' changed in GCC 9.1}   "" { target *-*-* } 107 } fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'S1p' changed in GCC 9.1}  "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S2p' changed in GCC 9.1}  "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S4p' changed in GCC 9.1}  "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'S8p' changed in GCC 9.1}  "" { target *-*-* } 111 } f8p_stdarg */
+
+/* No change in parameter passing in GCC 9.1 for line 112 (f16p_stdarg).
+   Should not warn.  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { target *-*-* } 112 } f16p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 114-118 (g1_stdarg,
+   g2_stdarg, g4_stdarg, g8_stdarg, g16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 120-124 (gp_stdarg,
+   g1p_stdarg, g2p_stdarg, g4p_stdarg, g8p_stdarg), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'S16p' changed in GCC 9.1} "" { xfail *-*-* } 125 } g16p_stdarg */
diff --git a/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align8-O2.C b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align8-O2.C
new file mode 100644
index 00000000000..b1764d97ea0
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning-align8-O2.C
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps -Wno-narrowing" } */
+
+#define ALIGN 8
+#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 18 } } */
+
+/* In f16, f16p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 4 } } */
+
+/* In f1, f2, f4, f8, f16, fp, f1p, f2p, f4p, f8p, f16p stack versions:  */
+/* { dg-final { scan-assembler-times "and\tw0, w0, 1" 11 } } */
diff --git a/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning.h b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning.h
new file mode 100644
index 00000000000..3940b714ef8
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/bitfield-abi-warning.h
@@ -0,0 +1,125 @@
+#include <stdarg.h>
+
+typedef unsigned long long ull __attribute__((aligned(ALIGN)));
+
+#ifndef EXTRA
+#define EXTRA unsigned long long x;
+#endif
+
+struct S1  { __attribute__((aligned(1))) ull i : 1; EXTRA };
+struct S2  { __attribute__((aligned(2))) ull i : 1; EXTRA };
+struct S4  { __attribute__((aligned(4))) ull i : 1; EXTRA };
+struct S8  { __attribute__((aligned(8))) ull i : 1; EXTRA };
+struct S16 { __attribute__((aligned(16))) ull i : 1; EXTRA };
+
+struct Sp   { ull i : 1; EXTRA }__attribute__((packed));
+struct S1p  { __attribute__((packed, aligned(1))) ull i : 1; EXTRA };
+struct S2p  { __attribute__((packed, aligned(2))) ull i : 1; EXTRA };
+struct S4p  { __attribute__((packed, aligned(4))) ull i : 1; EXTRA };
+struct S8p  { __attribute__((packed, aligned(8))) ull i : 1; EXTRA };
+struct S16p { __attribute__((packed, aligned(16))) ull i : 1; EXTRA };
+
+/* Bitfield in registers.  */
+#define PARAMS(xx) int a0, struct S##xx s, ull a1
+/* Bitfield passed by the stack.  */
+#define PARAMS_STACK(xx) int a0, ull a1, ull a2, ull a3, ull a4, ull a5, ull a6, ull a7, ull a8, struct S##xx t
+/* Bitfield passed via stdarg.  */
+#define PARAMS_STDARG(xx) int a0, ...
+
+#define CODE(xx)				\
+  return s.i;
+
+#define CODE_STACK(xx)				\
+  return t.i;
+
+#define CODE_STDARG(xx)				\
+  va_list ap;					\
+  struct S##xx arg;				\
+  __builtin_va_start(ap,a0);			\
+  arg = __builtin_va_arg(ap, struct S##xx);	\
+  return arg.i;
+
+#define ARGS(xx) x, (struct S##xx) { x }, x
+#define ARGS_STACK(xx) x, x, x, x, x, x, x, x, x, (struct S##xx) { x }
+#define ARGS_STDARG(xx) x, (struct S##xx) { x }
+
+/* Bitfield in registers.  */
+int __attribute__ ((noipa)) f1 (PARAMS(1))  { CODE(1) }
+int __attribute__ ((noipa)) f2 (PARAMS(2))  { CODE(2) }
+int __attribute__ ((noipa)) f4 (PARAMS(4))  { CODE(4) }
+int __attribute__ ((noipa)) f8 (PARAMS(8))  { CODE(8) }
+int __attribute__ ((noipa)) f16(PARAMS(16)) { CODE(16) }
+
+int __attribute__ ((noipa)) fp  (PARAMS(p))   { CODE(p) }
+int __attribute__ ((noipa)) f1p (PARAMS(1p))  { CODE(1p) }
+int __attribute__ ((noipa)) f2p (PARAMS(2p))  { CODE(2p) }
+int __attribute__ ((noipa)) f4p (PARAMS(4p))  { CODE(4p) }
+int __attribute__ ((noipa)) f8p (PARAMS(8p))  { CODE(8p) }
+int __attribute__ ((noipa)) f16p(PARAMS(16p)) { CODE(16p) }
+
+int g1 (int x) { return f1 (ARGS(1)); }
+int g2 (int x) { return f2 (ARGS(2)); }
+int g4 (int x) { return f4 (ARGS(4)); }
+int g8 (int x) { return f8 (ARGS(8)); }
+int g16(int x) { return f16 (ARGS(16)); }
+
+int gp  (int x) { return fp   (ARGS(p)); }
+int g1p (int x) { return f1p  (ARGS(1p)); }
+int g2p (int x) { return f2p  (ARGS(2p)); }
+int g4p (int x) { return f4p  (ARGS(4p)); }
+int g8p (int x) { return f8p  (ARGS(8p)); }
+int g16p(int x) { return f16p (ARGS(16p)); }
+
+/* Bitfield in the stack.  */
+int __attribute__ ((noipa)) f1_stack (PARAMS_STACK(1))  { CODE_STACK(1) }
+int __attribute__ ((noipa)) f2_stack (PARAMS_STACK(2))  { CODE_STACK(2) }
+int __attribute__ ((noipa)) f4_stack (PARAMS_STACK(4))  { CODE_STACK(4) }
+int __attribute__ ((noipa)) f8_stack (PARAMS_STACK(8))  { CODE_STACK(8) }
+int __attribute__ ((noipa)) f16_stack(PARAMS_STACK(16)) { CODE_STACK(16) }
+
+int __attribute__ ((noipa)) fp_stack  (PARAMS_STACK(p))   { CODE_STACK(p) }
+int __attribute__ ((noipa)) f1p_stack (PARAMS_STACK(1p))  { CODE_STACK(1p) }
+int __attribute__ ((noipa)) f2p_stack (PARAMS_STACK(2p))  { CODE_STACK(2p) }
+int __attribute__ ((noipa)) f4p_stack (PARAMS_STACK(4p))  { CODE_STACK(4p) }
+int __attribute__ ((noipa)) f8p_stack (PARAMS_STACK(8p))  { CODE_STACK(8p) }
+int __attribute__ ((noipa)) f16p_stack(PARAMS_STACK(16p)) { CODE_STACK(16p) }
+
+int g1_stack (int x) { return f1_stack (ARGS_STACK(1)); }
+int g2_stack (int x) { return f2_stack (ARGS_STACK(2)); }
+int g4_stack (int x) { return f4_stack (ARGS_STACK(4)); }
+int g8_stack (int x) { return f8_stack (ARGS_STACK(8)); }
+int g16_stack(int x) { return f16_stack (ARGS_STACK(16)); }
+
+int gp_stack  (int x) { return fp_stack (ARGS_STACK(p)); }
+int g1p_stack (int x) { return f1p_stack (ARGS_STACK(1p)); }
+int g2p_stack (int x) { return f2p_stack (ARGS_STACK(2p)); }
+int g4p_stack (int x) { return f4p_stack (ARGS_STACK(4p)); }
+int g8p_stack (int x) { return f8p_stack (ARGS_STACK(8p)); }
+int g16p_stack(int x) { return f16p_stack (ARGS_STACK(16p)); }
+
+/* Bitfield  via stdarg.  */
+int __attribute__ ((noipa)) f1_stdarg (PARAMS_STDARG(1))  { CODE_STDARG(1) }
+int __attribute__ ((noipa)) f2_stdarg (PARAMS_STDARG(2))  { CODE_STDARG(2) }
+int __attribute__ ((noipa)) f4_stdarg (PARAMS_STDARG(4))  { CODE_STDARG(4) }
+int __attribute__ ((noipa)) f8_stdarg (PARAMS_STDARG(8))  { CODE_STDARG(8) }
+int __attribute__ ((noipa)) f16_stdarg(PARAMS_STDARG(16)) { CODE_STDARG(16) }
+
+int __attribute__ ((noipa)) fp_stdarg  (PARAMS_STDARG(p))   { CODE_STDARG(p) }
+int __attribute__ ((noipa)) f1p_stdarg (PARAMS_STDARG(1p))  { CODE_STDARG(1p) }
+int __attribute__ ((noipa)) f2p_stdarg (PARAMS_STDARG(2p))  { CODE_STDARG(2p) }
+int __attribute__ ((noipa)) f4p_stdarg (PARAMS_STDARG(4p))  { CODE_STDARG(4p) }
+int __attribute__ ((noipa)) f8p_stdarg (PARAMS_STDARG(8p))  { CODE_STDARG(8p) }
+int __attribute__ ((noipa)) f16p_stdarg(PARAMS_STDARG(16p)) { CODE_STDARG(16p) }
+
+int g1_stdarg (int x) { return f1_stdarg (ARGS_STDARG(1)); }
+int g2_stdarg (int x) { return f2_stdarg (ARGS_STDARG(2)); }
+int g4_stdarg (int x) { return f4_stdarg (ARGS_STDARG(4)); }
+int g8_stdarg (int x) { return f8_stdarg (ARGS_STDARG(8)); }
+int g16_stdarg(int x) { return f16_stdarg (ARGS_STDARG(16)); }
+
+int gp_stdarg  (int x) { return fp_stdarg (ARGS_STDARG(p)); }
+int g1p_stdarg (int x) { return f1p_stdarg (ARGS_STDARG(1p)); }
+int g2p_stdarg (int x) { return f2p_stdarg (ARGS_STDARG(2p)); }
+int g4p_stdarg (int x) { return f4p_stdarg (ARGS_STDARG(4p)); }
+int g8p_stdarg (int x) { return f8p_stdarg (ARGS_STDARG(8p)); }
+int g16p_stdarg(int x) { return f16p_stdarg (ARGS_STDARG(16p)); }
diff --git a/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align16-O2-extra.c b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align16-O2-extra.c
new file mode 100644
index 00000000000..3e38cac149d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align16-O2-extra.c
@@ -0,0 +1,86 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps" } */
+
+#define ALIGN 16
+//#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, f16, f16p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 12 { xfail *-*-* } } } */
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} "" { target *-*-* } 47 } f1 */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} "" { target *-*-* } 48 } f2 */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} "" { target *-*-* } 49 } f4 */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} "" { target *-*-* } 50 } f8 */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 53 }  fp */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Bitfield call argument in registers.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} ""  { target *-*-* } 60 } g1 */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} ""  { target *-*-* } 61 } g2 */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} ""  { target *-*-* } 62 } g4 */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} ""  { target *-*-* } 63 } g8 */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 66 }  gp */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 67 } g1p */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 68 } g2p */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 69 } g4p */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 70 } g8p */
+
+
+/* Bitfield parameter in stack.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} "" { target *-*-* } 74 } f1_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} "" { target *-*-* } 75 } f2_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} "" { target *-*-* } 76 } f4_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} "" { target *-*-* } 77 } f8_stack */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 80 }  fp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* Bitfield call argument in stack.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} ""  { target *-*-* } 87 } g1_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} ""  { target *-*-* } 88 } g2_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} ""  { target *-*-* } 89 } g4_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} ""  { target *-*-* } 90 } g8_stack */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 93 }  gp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* Bitfield parameter in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} "" { target *-*-* } 101 } f1_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} "" { target *-*-* } 102 } f2_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} "" { target *-*-* } 103 } f4_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} "" { target *-*-* } 104 } f8_stdarg */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 107 }  fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 111 } f8p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} ""  { target *-*-* } 114 } g1_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} ""  { target *-*-* } 115 } g2_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} ""  { target *-*-* } 116 } g4_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} ""  { target *-*-* } 117 } g8_stdarg */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 120 }  gp_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 121 } g1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 122 } g2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 123 } g4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 124 } g8p_stdarg */
diff --git a/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align16-O2.c b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align16-O2.c
new file mode 100644
index 00000000000..39c5f9228ee
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align16-O2.c
@@ -0,0 +1,87 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps" } */
+
+#define ALIGN 16
+#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, f16, f16p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 12 { xfail *-*-* } } } */
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} "" { target *-*-* } 47 } f1 */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} "" { target *-*-* } 48 } f2 */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} "" { target *-*-* } 49 } f4 */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} "" { target *-*-* } 50 } f8 */
+
+/* No change in parameter passing in GCC 9.1 for lines 53-57 (fp, f1p, f2p,
+   f4p, f8p) (because the argument fits in a single register).  Should not
+   warn, but aarch64_function_arg_boundary would need to take the argument size
+   into account as well as whether it's passed via registers or the stack.  */
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 53 }  fp */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Bitfield call argument in registers.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} ""  { target *-*-* } 60 } g1 */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} ""  { target *-*-* } 61 } g2 */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} ""  { target *-*-* } 62 } g4 */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} ""  { target *-*-* } 63 } g8 */
+
+/* No change in parameter passing in GCC 9.1 for lines 66-70 (gp, g1p, g2p,
+   g4p, g8p), no warning expected.  */
+
+
+/* Bitfield parameter in stack.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} "" { target *-*-* } 74 } f1_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} "" { target *-*-* } 75 } f2_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} "" { target *-*-* } 76 } f4_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} "" { target *-*-* } 77 } f8_stack */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 80 }  fp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* Bitfield call argument in stack.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} ""  { target *-*-* } 87 } g1_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} ""  { target *-*-* } 88 } g2_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} ""  { target *-*-* } 89 } g4_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} ""  { target *-*-* } 90 } g8_stack */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 93 }  gp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* Bitfield parameter in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} "" { target *-*-* } 101 } f1_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} "" { target *-*-* } 102 } f2_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} "" { target *-*-* } 103 } f4_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} "" { target *-*-* } 104 } f8_stdarg */
+
+/* Parameter passing for these should not have changed in GCC 9.1 (PR 105549).
+   Fortunately we warn. Note the discrepancy with lines 120-124 below: we warn
+   in the callee, but not in the caller.  */
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1} "" { target *-*-* } 107 }  fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 111 } f8p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* { dg-note {parameter passing for argument of type 'struct S1' changed in GCC 9.1} ""  { target *-*-* } 114 } g1_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2' changed in GCC 9.1} ""  { target *-*-* } 115 } g2_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4' changed in GCC 9.1} ""  { target *-*-* } 116 } g4_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8' changed in GCC 9.1} ""  { target *-*-* } 117 } g8_stdarg */
+
+/* No change in parameter passing in GCC 9.1 for lines 120-124 (gp_stdarg
+   g1p_stdarg, g2p_stdarg, g4p_stdarg, g8p_stdarg), no warning expected.  */
diff --git a/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align32-O2-extra.c b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align32-O2-extra.c
new file mode 100644
index 00000000000..70671ceda09
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align32-O2-extra.c
@@ -0,0 +1,119 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps" } */
+
+#define ALIGN 32
+//#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+
+/* In f1, f2, f4, f8, f16 (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[x1\\\]" 10 } } */
+
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* In f16p (and stdarg version):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 2 { xfail *-*-* } } } */
+
+/* In f1_stack, f2_stack, f4_stack, f8_stack, f16_stack, f8p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx\[0-9\]+, \\\[sp, 8\\\]" 6 { xfail *-*-* } } } */
+
+/* In fp_stack, f1p_stack:  */
+/* { dg-final { scan-assembler-times "ldrb\tw0, \\\[sp, 8\\\]" 2 { xfail *-*-* } } } */
+
+/* In f2p_stack:  */
+/* { dg-final { scan-assembler-times "ldrh\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f4p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f16p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[sp, 16\\\]" 1 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 47-51 (f1, f2, f4, f8, f16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 53-57 (fp, f1p, f2p,
+   f4p, f8p) because the argument fits in a single register.  Should not warn,
+   but aarch64_function_arg_boundary would need to take the argument size into
+   account as well as whether it's passed via registers or the stack.  */
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}  "" { target *-*-* } 53 } fp */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Changed in GCC 9.1, but we fail to emit a warning since GCC 11 (was OK with GCC 9).  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { xfail *-*-* } 58 } f16p */
+
+
+/* Bitfield call argument in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 60-64 (g1, g2, g4, g8, g16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 66-70 (gp, g1p, g2p,
+   g4p, g8p), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { xfail *-*-* } 71 } g16p */
+
+
+/* Bitfield parameter in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 74-78 (f1_stack,
+   f2_stack, f4_stack, f8_stack, f16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* Changed in GCC 9.1.  */
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}  "" { target *-*-* } 80 } fp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* No change in parameter passing in GCC 9.1 for line 85 (f16p_stack) because
+   the overall alignment is >= 16.  No warning expected.  */
+
+
+/* Bitfield call argument in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 87-91 (g1_stack,
+   g2_stack, g4_stack, g8_stack, g16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}  "" { target *-*-* } 93 } gp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* No change in parameter passing in GCC 9.1 for line 98 (g16p_stack).  No
+   warning expected.  */
+
+
+/* Bitfield parameter in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 101-105 (f1_stdarg,
+   f2_stdarg, f4_stdarg, f8_stdarg, f16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}   "" { target *-*-* } 107 } fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1}  "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1}  "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1}  "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1}  "" { target *-*-* } 111 } f8p_stdarg */
+
+/* No change in parameter passing in GCC 9.1 for line 112 (f16p_stdarg).
+   Should not warn.  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { target *-*-* } 112 } f16p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 114-118 (g1_stdarg,
+   g2_stdarg, g4_stdarg, g8_stdarg, g16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 120-124 (gp_stdarg,
+   g1p_stdarg, g2p_stdarg, g4p_stdarg, g8p_stdarg), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { xfail *-*-* } 125 } g16p_stdarg */
diff --git a/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align32-O2.c b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align32-O2.c
new file mode 100644
index 00000000000..757a2f1543c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align32-O2.c
@@ -0,0 +1,119 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps" } */
+
+#define ALIGN 32
+#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, f16 (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[x1\\\]" 10 } } */
+
+/* In fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 10 { xfail *-*-* } } } */
+
+/* In f16p (and stdarg version):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 2 { xfail *-*-* } } } */
+
+/* In f1_stack, f2_stack, f4_stack, f8_stack, f16_stack, f8p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx\[0-9\]+, \\\[sp, 8\\\]" 6 { xfail *-*-* } } } */
+
+/* In fp_stack, f1p_stack:  */
+/* { dg-final { scan-assembler-times "ldrb\tw0, \\\[sp, 8\\\]" 2 { xfail *-*-* } } } */
+
+/* In f2p_stack:  */
+/* { dg-final { scan-assembler-times "ldrh\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f4p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tw0, \\\[sp, 8\\\]" 1 { xfail *-*-* } } } */
+
+/* In f16p_stack:  */
+/* { dg-final { scan-assembler-times "ldr\tx0, \\\[sp, 16\\\]" 1 { xfail *-*-* } } } */
+
+/* Bitfield parameter in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 47-51 (f1, f2, f4, f8, f16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 53-57 (fp, f1p, f2p,
+   f4p, f8p) because the argument fits in a single register.  Should not warn,
+   but aarch64_function_arg_boundary would need to take the argument size into
+   account as well as whether it's passed via registers or the stack.  */
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}  "" { target *-*-* } 53 } fp */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 54 } f1p */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 55 } f2p */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 56 } f4p */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 57 } f8p */
+
+/* Changed in GCC 9.1, but we fail to emit a warning since GCC 11 (was OK with GCC 9).  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { xfail *-*-* } 58 } f16p */
+
+
+/* Bitfield call argument in registers.  */
+/* No change in parameter passing in GCC 9.1 for lines 60-64 (g1, g2, g4, g8, g16)
+   because the overall alignment is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 66-70 (gp, g1p, g2p,
+   g4p, g8p), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { xfail *-*-* } 71 } g16p */
+
+
+/* Bitfield parameter in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 74-78 (f1_stack,
+   f2_stack, f4_stack, f8_stack, f16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}  "" { target *-*-* } 80 } fp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 81 } f1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 82 } f2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 83 } f4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 84 } f8p_stack */
+
+/* No change in parameter passing in GCC 9.1 for line 85 (f16p_stack) because
+   the overall alignment is >= 16.  No warning expected.  */
+
+/* Bitfield call argument in stack.  */
+/* No change in parameter passing in GCC 9.1 for lines 87-91 (g1_stack,
+   g2_stack, g4_stack, g8_stack, g16_stack) because the overall alignment is >
+   16.  No warning expected.  */
+
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}  "" { target *-*-* } 93 } gp_stack */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1} "" { target *-*-* } 94 } g1p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1} "" { target *-*-* } 95 } g2p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1} "" { target *-*-* } 96 } g4p_stack */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1} "" { target *-*-* } 97 } g8p_stack */
+
+
+/* No change in parameter passing in GCC 9.1 for line 98 (g16p_stack).  No
+   warning expected.  */
+
+
+/* Bitfield parameter in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 101-105 (f1_stdarg,
+   f2_stdarg, f4_stdarg, f8_stdarg, f16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* Parameter passing for these should not have changed in GCC 9.1 (PR 105549).
+   Fortunately we warn. Note the discrepancy with lines 120-124 below: we warn
+   in the callee, but not in the caller.  */
+/* { dg-note {parameter passing for argument of type 'struct Sp' changed in GCC 9.1}   "" { target *-*-* } 107 } fp_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S1p' changed in GCC 9.1}  "" { target *-*-* } 108 } f1p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S2p' changed in GCC 9.1}  "" { target *-*-* } 109 } f2p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S4p' changed in GCC 9.1}  "" { target *-*-* } 110 } f4p_stdarg */
+/* { dg-note {parameter passing for argument of type 'struct S8p' changed in GCC 9.1}  "" { target *-*-* } 111 } f8p_stdarg */
+
+/* No change in parameter passing in GCC 9.1 for line 112 (f16p_stdarg).
+   Should not warn.  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { target *-*-* } 112 } f16p_stdarg */
+
+/* Bitfield call argument in stdarg.  */
+/* No change in parameter passing in GCC 9.1 for lines 114-118 (g1_stdarg,
+   g2_stdarg, g4_stdarg, g8_stdarg, g16_stdarg) because the overall alignment
+   is > 16.  No warning expected.  */
+
+/* No change in parameter passing in GCC 9.1 for lines 120-124 (gp_stdarg,
+   g1p_stdarg, g2p_stdarg, g4p_stdarg, g8p_stdarg), no warning expected.  */
+
+/* Changed in GCC 9.1, but we fail to emit a warning.  */
+/* { dg-note {parameter passing for argument of type 'struct S16p' changed in GCC 9.1} "" { xfail *-*-* } 125 } g16p_stdarg */
diff --git a/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align8-O2.c b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align8-O2.c
new file mode 100644
index 00000000000..cb2a945a819
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning-align8-O2.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps" } */
+
+#define ALIGN 8
+#define EXTRA
+
+#include "bitfield-abi-warning.h"
+
+/* In f1, f2, f4, f8, fp, f1p, f2p, f4p, f8p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w1, 1" 18 } } */
+
+/* In f16, f16p (and stdarg versions):  */
+/* { dg-final { scan-assembler-times "and\tw0, w2, 1" 4 } } */
+
+/* In f1, f2, f4, f8, f16, fp, f1p, f2p, f4p, f8p, f16p stack versions:  */
+/* { dg-final { scan-assembler-times "and\tw0, w0, 1" 11 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning.h b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning.h
new file mode 100644
index 00000000000..3940b714ef8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/bitfield-abi-warning.h
@@ -0,0 +1,125 @@
+#include <stdarg.h>
+
+typedef unsigned long long ull __attribute__((aligned(ALIGN)));
+
+#ifndef EXTRA
+#define EXTRA unsigned long long x;
+#endif
+
+struct S1  { __attribute__((aligned(1))) ull i : 1; EXTRA };
+struct S2  { __attribute__((aligned(2))) ull i : 1; EXTRA };
+struct S4  { __attribute__((aligned(4))) ull i : 1; EXTRA };
+struct S8  { __attribute__((aligned(8))) ull i : 1; EXTRA };
+struct S16 { __attribute__((aligned(16))) ull i : 1; EXTRA };
+
+struct Sp   { ull i : 1; EXTRA }__attribute__((packed));
+struct S1p  { __attribute__((packed, aligned(1))) ull i : 1; EXTRA };
+struct S2p  { __attribute__((packed, aligned(2))) ull i : 1; EXTRA };
+struct S4p  { __attribute__((packed, aligned(4))) ull i : 1; EXTRA };
+struct S8p  { __attribute__((packed, aligned(8))) ull i : 1; EXTRA };
+struct S16p { __attribute__((packed, aligned(16))) ull i : 1; EXTRA };
+
+/* Bitfield in registers.  */
+#define PARAMS(xx) int a0, struct S##xx s, ull a1
+/* Bitfield passed by the stack.  */
+#define PARAMS_STACK(xx) int a0, ull a1, ull a2, ull a3, ull a4, ull a5, ull a6, ull a7, ull a8, struct S##xx t
+/* Bitfield passed via stdarg.  */
+#define PARAMS_STDARG(xx) int a0, ...
+
+#define CODE(xx)				\
+  return s.i;
+
+#define CODE_STACK(xx)				\
+  return t.i;
+
+#define CODE_STDARG(xx)				\
+  va_list ap;					\
+  struct S##xx arg;				\
+  __builtin_va_start(ap,a0);			\
+  arg = __builtin_va_arg(ap, struct S##xx);	\
+  return arg.i;
+
+#define ARGS(xx) x, (struct S##xx) { x }, x
+#define ARGS_STACK(xx) x, x, x, x, x, x, x, x, x, (struct S##xx) { x }
+#define ARGS_STDARG(xx) x, (struct S##xx) { x }
+
+/* Bitfield in registers.  */
+int __attribute__ ((noipa)) f1 (PARAMS(1))  { CODE(1) }
+int __attribute__ ((noipa)) f2 (PARAMS(2))  { CODE(2) }
+int __attribute__ ((noipa)) f4 (PARAMS(4))  { CODE(4) }
+int __attribute__ ((noipa)) f8 (PARAMS(8))  { CODE(8) }
+int __attribute__ ((noipa)) f16(PARAMS(16)) { CODE(16) }
+
+int __attribute__ ((noipa)) fp  (PARAMS(p))   { CODE(p) }
+int __attribute__ ((noipa)) f1p (PARAMS(1p))  { CODE(1p) }
+int __attribute__ ((noipa)) f2p (PARAMS(2p))  { CODE(2p) }
+int __attribute__ ((noipa)) f4p (PARAMS(4p))  { CODE(4p) }
+int __attribute__ ((noipa)) f8p (PARAMS(8p))  { CODE(8p) }
+int __attribute__ ((noipa)) f16p(PARAMS(16p)) { CODE(16p) }
+
+int g1 (int x) { return f1 (ARGS(1)); }
+int g2 (int x) { return f2 (ARGS(2)); }
+int g4 (int x) { return f4 (ARGS(4)); }
+int g8 (int x) { return f8 (ARGS(8)); }
+int g16(int x) { return f16 (ARGS(16)); }
+
+int gp  (int x) { return fp   (ARGS(p)); }
+int g1p (int x) { return f1p  (ARGS(1p)); }
+int g2p (int x) { return f2p  (ARGS(2p)); }
+int g4p (int x) { return f4p  (ARGS(4p)); }
+int g8p (int x) { return f8p  (ARGS(8p)); }
+int g16p(int x) { return f16p (ARGS(16p)); }
+
+/* Bitfield in the stack.  */
+int __attribute__ ((noipa)) f1_stack (PARAMS_STACK(1))  { CODE_STACK(1) }
+int __attribute__ ((noipa)) f2_stack (PARAMS_STACK(2))  { CODE_STACK(2) }
+int __attribute__ ((noipa)) f4_stack (PARAMS_STACK(4))  { CODE_STACK(4) }
+int __attribute__ ((noipa)) f8_stack (PARAMS_STACK(8))  { CODE_STACK(8) }
+int __attribute__ ((noipa)) f16_stack(PARAMS_STACK(16)) { CODE_STACK(16) }
+
+int __attribute__ ((noipa)) fp_stack  (PARAMS_STACK(p))   { CODE_STACK(p) }
+int __attribute__ ((noipa)) f1p_stack (PARAMS_STACK(1p))  { CODE_STACK(1p) }
+int __attribute__ ((noipa)) f2p_stack (PARAMS_STACK(2p))  { CODE_STACK(2p) }
+int __attribute__ ((noipa)) f4p_stack (PARAMS_STACK(4p))  { CODE_STACK(4p) }
+int __attribute__ ((noipa)) f8p_stack (PARAMS_STACK(8p))  { CODE_STACK(8p) }
+int __attribute__ ((noipa)) f16p_stack(PARAMS_STACK(16p)) { CODE_STACK(16p) }
+
+int g1_stack (int x) { return f1_stack (ARGS_STACK(1)); }
+int g2_stack (int x) { return f2_stack (ARGS_STACK(2)); }
+int g4_stack (int x) { return f4_stack (ARGS_STACK(4)); }
+int g8_stack (int x) { return f8_stack (ARGS_STACK(8)); }
+int g16_stack(int x) { return f16_stack (ARGS_STACK(16)); }
+
+int gp_stack  (int x) { return fp_stack (ARGS_STACK(p)); }
+int g1p_stack (int x) { return f1p_stack (ARGS_STACK(1p)); }
+int g2p_stack (int x) { return f2p_stack (ARGS_STACK(2p)); }
+int g4p_stack (int x) { return f4p_stack (ARGS_STACK(4p)); }
+int g8p_stack (int x) { return f8p_stack (ARGS_STACK(8p)); }
+int g16p_stack(int x) { return f16p_stack (ARGS_STACK(16p)); }
+
+/* Bitfield  via stdarg.  */
+int __attribute__ ((noipa)) f1_stdarg (PARAMS_STDARG(1))  { CODE_STDARG(1) }
+int __attribute__ ((noipa)) f2_stdarg (PARAMS_STDARG(2))  { CODE_STDARG(2) }
+int __attribute__ ((noipa)) f4_stdarg (PARAMS_STDARG(4))  { CODE_STDARG(4) }
+int __attribute__ ((noipa)) f8_stdarg (PARAMS_STDARG(8))  { CODE_STDARG(8) }
+int __attribute__ ((noipa)) f16_stdarg(PARAMS_STDARG(16)) { CODE_STDARG(16) }
+
+int __attribute__ ((noipa)) fp_stdarg  (PARAMS_STDARG(p))   { CODE_STDARG(p) }
+int __attribute__ ((noipa)) f1p_stdarg (PARAMS_STDARG(1p))  { CODE_STDARG(1p) }
+int __attribute__ ((noipa)) f2p_stdarg (PARAMS_STDARG(2p))  { CODE_STDARG(2p) }
+int __attribute__ ((noipa)) f4p_stdarg (PARAMS_STDARG(4p))  { CODE_STDARG(4p) }
+int __attribute__ ((noipa)) f8p_stdarg (PARAMS_STDARG(8p))  { CODE_STDARG(8p) }
+int __attribute__ ((noipa)) f16p_stdarg(PARAMS_STDARG(16p)) { CODE_STDARG(16p) }
+
+int g1_stdarg (int x) { return f1_stdarg (ARGS_STDARG(1)); }
+int g2_stdarg (int x) { return f2_stdarg (ARGS_STDARG(2)); }
+int g4_stdarg (int x) { return f4_stdarg (ARGS_STDARG(4)); }
+int g8_stdarg (int x) { return f8_stdarg (ARGS_STDARG(8)); }
+int g16_stdarg(int x) { return f16_stdarg (ARGS_STDARG(16)); }
+
+int gp_stdarg  (int x) { return fp_stdarg (ARGS_STDARG(p)); }
+int g1p_stdarg (int x) { return f1p_stdarg (ARGS_STDARG(1p)); }
+int g2p_stdarg (int x) { return f2p_stdarg (ARGS_STDARG(2p)); }
+int g4p_stdarg (int x) { return f4p_stdarg (ARGS_STDARG(4p)); }
+int g8p_stdarg (int x) { return f8p_stdarg (ARGS_STDARG(8p)); }
+int g16p_stdarg(int x) { return f16p_stdarg (ARGS_STDARG(16p)); }
