[committed,1/2] riscv: thead: Add support for the XTheadMemIdx ISA extension

Message ID 20231031171123.569951-1-christoph.muellner@vrull.eu
State Unresolved
Headers
Series [committed,1/2] riscv: thead: Add support for the XTheadMemIdx ISA extension |

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Commit Message

Christoph Müllner Oct. 31, 2023, 5:11 p.m. UTC
  From: Christoph Müllner <christoph.muellner@vrull.eu>

The XTheadMemIdx ISA extension provides a additional load and store
instructions with new addressing modes.

The following memory accesses types are supported:
* load: b,bu,h,hu,w,wu,d
* store: b,h,w,d

The following addressing modes are supported:
* immediate offset with PRE_MODIFY or POST_MODIFY (22 instructions):
  l<ltype>.ia, l<ltype>.ib, s<stype>.ia, s<stype>.ib
* register offset with additional immediate offset (11 instructions):
  lr<ltype>, sr<stype>
* zero-extended register offset with additional immediate offset
  (11 instructions): lur<ltype>, sur<stype>

The RISC-V base ISA does not support index registers, so the changes
are kept separate from the RISC-V standard support as much as possible.

To combine the shift/multiply instructions into the memory access
instructions, this patch comes with a few insn_and_split optimizations
that allow the combiner to do this task.

Handling the different cases of extensions results in a couple of INSNs
that look redundant on first view, but they are just the equivalence
of what we already have for Zbb as well. The only difference is, that
we have much more load instructions.

We already have a constraint with the name 'th_f_fmv', therefore,
the new constraints follow this pattern and have the same length
as required ('th_m_mia', 'th_m_mib', 'th_m_mir', 'th_m_miu').

The added tests ensure that this feature won't regress without notice.
Testing: GCC regression test suite, GCC bootstrap build, and
SPEC CPU 2017 intrate (base&peak) on C920.

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>

gcc/ChangeLog:

	* config/riscv/constraints.md (th_m_mia): New constraint.
	(th_m_mib): Likewise.
	(th_m_mir): Likewise.
	(th_m_miu): Likewise.
	* config/riscv/riscv-protos.h (enum riscv_address_type):
	Add new address types ADDRESS_REG_REG, ADDRESS_REG_UREG,
	and ADDRESS_REG_WB and their documentation.
	(struct riscv_address_info): Add new field 'shift' and
	document the field usage for the new address types.
	(riscv_valid_base_register_p): New prototype.
	(th_memidx_legitimate_modify_p): Likewise.
	(th_memidx_legitimate_index_p): Likewise.
	(th_classify_address): Likewise.
	(th_output_move): Likewise.
	(th_print_operand_address): Likewise.
	* config/riscv/riscv.cc (riscv_index_reg_class):
	Return GR_REGS for XTheadMemIdx.
	(riscv_regno_ok_for_index_p): Add support for XTheadMemIdx.
	(riscv_classify_address): Call th_classify_address() on top.
	(riscv_output_move): Call th_output_move() on top.
	(riscv_print_operand_address): Call th_print_operand_address()
	on top.
	* config/riscv/riscv.h (HAVE_POST_MODIFY_DISP): New macro.
	(HAVE_PRE_MODIFY_DISP): Likewise.
	* config/riscv/riscv.md (zero_extendqi<SUPERQI:mode>2): Disable
	for XTheadMemIdx.
	(*zero_extendqi<SUPERQI:mode>2_internal): Convert to expand,
	create INSN with same name and disable it for XTheadMemIdx.
	(extendsidi2): Likewise.
	(*extendsidi2_internal): Disable for XTheadMemIdx.
	* config/riscv/thead.cc (valid_signed_immediate): New helper
	function.
	(th_memidx_classify_address_modify): New function.
	(th_memidx_legitimate_modify_p): Likewise.
	(th_memidx_output_modify): Likewise.
	(is_memidx_mode): Likewise.
	(th_memidx_classify_address_index): Likewise.
	(th_memidx_legitimate_index_p): Likewise.
	(th_memidx_output_index): Likewise.
	(th_classify_address): Likewise.
	(th_output_move): Likewise.
	(th_print_operand_address): Likewise.
	* config/riscv/thead.md (*th_memidx_operand): New splitter.
	(*th_memidx_zero_extendqi<SUPERQI:mode>2): New INSN.
	(*th_memidx_extendsidi2): Likewise.
	(*th_memidx_zero_extendsidi2): Likewise.
	(*th_memidx_zero_extendhi<GPR:mode>2): Likewise.
	(*th_memidx_extend<SHORT:mode><SUPERQI:mode>2): Likewise.
	(*th_memidx_bb_zero_extendsidi2): Likewise.
	(*th_memidx_bb_zero_extendhi<GPR:mode>2): Likewise.
	(*th_memidx_bb_extendhi<GPR:mode>2): Likewise.
	(*th_memidx_bb_extendqi<SUPERQI:mode>2): Likewise.
	(TH_M_ANYI): New mode iterator.
	(TH_M_NOEXTI): Likewise.
	(*th_memidx_I_a): New combiner optimization.
	(*th_memidx_I_b): Likewise.
	(*th_memidx_I_c): Likewise.
	(*th_memidx_US_a): Likewise.
	(*th_memidx_US_b): Likewise.
	(*th_memidx_US_c): Likewise.
	(*th_memidx_UZ_a): Likewise.
	(*th_memidx_UZ_b): Likewise.
	(*th_memidx_UZ_c): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/xtheadmemidx-helpers.h: New test.
	* gcc.target/riscv/xtheadmemidx-index-update.c: New test.
	* gcc.target/riscv/xtheadmemidx-index-xtheadbb-update.c: New test.
	* gcc.target/riscv/xtheadmemidx-index-xtheadbb.c: New test.
	* gcc.target/riscv/xtheadmemidx-index.c: New test.
	* gcc.target/riscv/xtheadmemidx-modify-xtheadbb.c: New test.
	* gcc.target/riscv/xtheadmemidx-modify.c: New test.
	* gcc.target/riscv/xtheadmemidx-uindex-update.c: New test.
	* gcc.target/riscv/xtheadmemidx-uindex-xtheadbb-update.c: New test.
	* gcc.target/riscv/xtheadmemidx-uindex-xtheadbb.c: New test.
	* gcc.target/riscv/xtheadmemidx-uindex.c: New test.
---
 gcc/config/riscv/constraints.md               |  26 +
 gcc/config/riscv/riscv-protos.h               |  29 ++
 gcc/config/riscv/riscv.cc                     |  24 +-
 gcc/config/riscv/riscv.h                      |   4 +-
 gcc/config/riscv/riscv.md                     |  26 +-
 gcc/config/riscv/thead.cc                     | 452 ++++++++++++++++++
 gcc/config/riscv/thead.md                     | 433 ++++++++++++++++-
 .../gcc.target/riscv/xtheadmemidx-helpers.h   | 152 ++++++
 .../riscv/xtheadmemidx-index-update.c         |  27 ++
 .../xtheadmemidx-index-xtheadbb-update.c      |  27 ++
 .../riscv/xtheadmemidx-index-xtheadbb.c       |  36 ++
 .../gcc.target/riscv/xtheadmemidx-index.c     |  36 ++
 .../riscv/xtheadmemidx-modify-xtheadbb.c      |  74 +++
 .../gcc.target/riscv/xtheadmemidx-modify.c    |  74 +++
 .../riscv/xtheadmemidx-uindex-update.c        |  27 ++
 .../xtheadmemidx-uindex-xtheadbb-update.c     |  27 ++
 .../riscv/xtheadmemidx-uindex-xtheadbb.c      |  44 ++
 .../gcc.target/riscv/xtheadmemidx-uindex.c    |  44 ++
 18 files changed, 1548 insertions(+), 14 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-helpers.h
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-update.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb-update.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-index.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify-xtheadbb.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-update.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb-update.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex.c
  

Patch

diff --git a/gcc/config/riscv/constraints.md b/gcc/config/riscv/constraints.md
index 07ee14dd689..68be4515c04 100644
--- a/gcc/config/riscv/constraints.md
+++ b/gcc/config/riscv/constraints.md
@@ -220,3 +220,29 @@  (define_memory_constraint "Wdm"
   "Vector duplicate memory operand"
   (and (match_code "mem")
        (match_code "reg" "0")))
+
+;; Vendor ISA extension constraints.
+
+(define_memory_constraint "th_m_mia"
+  "@internal
+   A MEM with a valid address for th.[l|s]*ia instructions."
+  (and (match_code "mem")
+       (match_test "th_memidx_legitimate_modify_p (op, true)")))
+
+(define_memory_constraint "th_m_mib"
+  "@internal
+   A MEM with a valid address for th.[l|s]*ib instructions."
+  (and (match_code "mem")
+       (match_test "th_memidx_legitimate_modify_p (op, false)")))
+
+(define_memory_constraint "th_m_mir"
+  "@internal
+   A MEM with a valid address for th.[l|s]*r* instructions."
+  (and (match_code "mem")
+       (match_test "th_memidx_legitimate_index_p (op, false)")))
+
+(define_memory_constraint "th_m_miu"
+  "@internal
+   A MEM with a valid address for th.[l|s]*ur* instructions."
+  (and (match_code "mem")
+       (match_test "th_memidx_legitimate_index_p (op, true)")))
diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h
index 150b61bb5b5..fde360327c1 100644
--- a/gcc/config/riscv/riscv-protos.h
+++ b/gcc/config/riscv/riscv-protos.h
@@ -43,6 +43,15 @@  enum riscv_symbol_type {
        A natural register + offset address.  The register satisfies
        riscv_valid_base_register_p and the offset is a const_arith_operand.
 
+   ADDRESS_REG_REG
+       A base register indexed by (optionally scaled) register.
+
+   ADDRESS_REG_UREG
+       A base register indexed by (optionally scaled) zero-extended register.
+
+   ADDRESS_REG_WB
+       A base register indexed by immediate offset with writeback.
+
    ADDRESS_LO_SUM
        A LO_SUM rtx.  The first operand is a valid base register and
        the second operand is a symbolic address.
@@ -54,6 +63,9 @@  enum riscv_symbol_type {
        A constant symbolic address.  */
 enum riscv_address_type {
   ADDRESS_REG,
+  ADDRESS_REG_REG,
+  ADDRESS_REG_UREG,
+  ADDRESS_REG_WB,
   ADDRESS_LO_SUM,
   ADDRESS_CONST_INT,
   ADDRESS_SYMBOLIC
@@ -67,6 +79,13 @@  enum riscv_address_type {
    ADDRESS_REG
        REG is the base register and OFFSET is the constant offset.
 
+   ADDRESS_REG_REG and ADDRESS_REG_UREG
+       REG is the base register and OFFSET is the index register.
+
+   ADDRESS_REG_WB
+       REG is the base register, OFFSET is the constant offset, and
+       shift is the shift amount for the offset.
+
    ADDRESS_LO_SUM
        REG and OFFSET are the operands to the LO_SUM and SYMBOL_TYPE
        is the type of symbol it references.
@@ -78,6 +97,7 @@  struct riscv_address_info {
   rtx reg;
   rtx offset;
   enum riscv_symbol_type symbol_type;
+  int shift;
 };
 
 /* Routines implemented in riscv.cc.  */
@@ -85,6 +105,7 @@  extern enum riscv_symbol_type riscv_classify_symbolic_expression (rtx);
 extern bool riscv_symbolic_constant_p (rtx, enum riscv_symbol_type *);
 extern int riscv_float_const_rtx_index_for_fli (rtx);
 extern int riscv_regno_mode_ok_for_base_p (int, machine_mode, bool);
+extern bool riscv_valid_base_register_p (rtx, machine_mode, bool);
 extern enum reg_class riscv_index_reg_class ();
 extern int riscv_regno_ok_for_index_p (int);
 extern int riscv_address_insns (rtx, machine_mode, bool);
@@ -603,6 +624,14 @@  extern void th_mempair_save_restore_regs (rtx[4], bool, machine_mode);
 #ifdef RTX_CODE
 extern const char*
 th_mempair_output_move (rtx[4], bool, machine_mode, RTX_CODE);
+extern bool th_memidx_legitimate_modify_p (rtx);
+extern bool th_memidx_legitimate_modify_p (rtx, bool);
+extern bool th_memidx_legitimate_index_p (rtx);
+extern bool th_memidx_legitimate_index_p (rtx, bool);
+extern bool th_classify_address (struct riscv_address_info *,
+					rtx, machine_mode, bool);
+extern const char *th_output_move (rtx, rtx);
+extern bool th_print_operand_address (FILE *, machine_mode, rtx);
 #endif
 
 extern bool riscv_use_divmod_expander (void);
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index ca9a2ca81d5..de6d9734da0 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -1084,6 +1084,9 @@  riscv_regno_mode_ok_for_base_p (int regno,
 enum reg_class
 riscv_index_reg_class ()
 {
+  if (TARGET_XTHEADMEMIDX)
+    return GR_REGS;
+
   return NO_REGS;
 }
 
@@ -1092,15 +1095,18 @@  riscv_index_reg_class ()
    but extensions might support that.  */
 
 int
-riscv_regno_ok_for_index_p (int)
+riscv_regno_ok_for_index_p (int regno)
 {
+  if (TARGET_XTHEADMEMIDX)
+    return riscv_regno_mode_ok_for_base_p (regno, VOIDmode, 1);
+
   return 0;
 }
 
 /* Return true if X is a valid base register for mode MODE.
    STRICT_P is true if REG_OK_STRICT is in effect.  */
 
-static bool
+bool
 riscv_valid_base_register_p (rtx x, machine_mode mode, bool strict_p)
 {
   if (!strict_p && GET_CODE (x) == SUBREG)
@@ -1342,6 +1348,9 @@  static bool
 riscv_classify_address (struct riscv_address_info *info, rtx x,
 			machine_mode mode, bool strict_p)
 {
+  if (th_classify_address (info, x, mode, strict_p))
+    return true;
+
   switch (GET_CODE (x))
     {
     case REG:
@@ -3386,6 +3395,10 @@  riscv_output_move (rtx dest, rtx src)
   machine_mode mode;
   bool dbl_p;
   unsigned width;
+  const char *insn;
+
+  if ((insn = th_output_move (dest, src)))
+    return insn;
 
   dest_code = GET_CODE (dest);
   src_code = GET_CODE (src);
@@ -5581,6 +5594,9 @@  riscv_print_operand_address (FILE *file, machine_mode mode ATTRIBUTE_UNUSED, rtx
 {
   struct riscv_address_info addr;
 
+  if (th_print_operand_address (file, mode, x))
+    return;
+
   if (riscv_classify_address (&addr, x, word_mode, true))
     switch (addr.type)
       {
@@ -5602,7 +5618,11 @@  riscv_print_operand_address (FILE *file, machine_mode mode ATTRIBUTE_UNUSED, rtx
       case ADDRESS_SYMBOLIC:
 	output_addr_const (file, riscv_strip_unspec_address (x));
 	return;
+
+      default:
+	gcc_unreachable ();
       }
+
   gcc_unreachable ();
 }
 
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 01645141935..eb162abcb92 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -1191,9 +1191,11 @@  extern void riscv_remove_unneeded_save_restore_calls (void);
 #define OPTIMIZE_MODE_SWITCHING(ENTITY) (TARGET_VECTOR)
 #define NUM_MODES_FOR_MODE_SWITCHING {VXRM_MODE_NONE, riscv_vector::FRM_NONE}
 
-
 /* The size difference between different RVV modes can be up to 64 times.
    e.g. RVVMF64BI vs RVVMF1BI on zvl512b, which is [1, 1] vs [64, 64].  */
 #define MAX_POLY_VARIANT 64
 
+#define HAVE_POST_MODIFY_DISP TARGET_XTHEADMEMIDX
+#define HAVE_PRE_MODIFY_DISP  TARGET_XTHEADMEMIDX
+
 #endif /* ! GCC_RISCV_H */
diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index 23d91331290..ae2217d0907 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -1662,7 +1662,7 @@  (define_insn_and_split "*zero_extendsidi2_internal"
   [(set (match_operand:DI     0 "register_operand"     "=r,r")
 	(zero_extend:DI
 	    (match_operand:SI 1 "nonimmediate_operand" " r,m")))]
-  "TARGET_64BIT && !TARGET_ZBA && !TARGET_XTHEADBB
+  "TARGET_64BIT && !TARGET_ZBA && !TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX
    && !(register_operand (operands[1], SImode)
         && reg_or_subregno (operands[1]) == VL_REGNUM)"
   "@
@@ -1690,7 +1690,7 @@  (define_insn_and_split "*zero_extendhi<GPR:mode>2"
   [(set (match_operand:GPR    0 "register_operand"     "=r,r")
 	(zero_extend:GPR
 	    (match_operand:HI 1 "nonimmediate_operand" " r,m")))]
-  "!TARGET_ZBB && !TARGET_XTHEADBB"
+  "!TARGET_ZBB && !TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX"
   "@
    #
    lhu\t%0,%1"
@@ -1709,11 +1709,17 @@  (define_insn_and_split "*zero_extendhi<GPR:mode>2"
    (set_attr "type" "load")
    (set_attr "mode" "<GPR:MODE>")])
 
-(define_insn "zero_extendqi<SUPERQI:mode>2"
+(define_expand "zero_extendqi<SUPERQI:mode>2"
+  [(set (match_operand:SUPERQI    0 "register_operand")
+	(zero_extend:SUPERQI
+	    (match_operand:QI 1 "nonimmediate_operand")))]
+  "")
+
+(define_insn "*zero_extendqi<SUPERQI:mode>2_internal"
   [(set (match_operand:SUPERQI 0 "register_operand"    "=r,r")
 	(zero_extend:SUPERQI
 	    (match_operand:QI 1 "nonimmediate_operand" " r,m")))]
-  ""
+  "!TARGET_XTHEADMEMIDX"
   "@
    andi\t%0,%1,0xff
    lbu\t%0,%1"
@@ -1728,11 +1734,17 @@  (define_insn "zero_extendqi<SUPERQI:mode>2"
 ;;
 ;;  ....................
 
-(define_insn "extendsidi2"
+(define_expand "extendsidi2"
   [(set (match_operand:DI     0 "register_operand"     "=r,r")
 	(sign_extend:DI
 	    (match_operand:SI 1 "nonimmediate_operand" " r,m")))]
-  "TARGET_64BIT"
+  "TARGET_64BIT")
+
+(define_insn "*extendsidi2_internal"
+  [(set (match_operand:DI     0 "register_operand"     "=r,r")
+	(sign_extend:DI
+	    (match_operand:SI 1 "nonimmediate_operand" " r,m")))]
+  "TARGET_64BIT && !TARGET_XTHEADMEMIDX"
   "@
    sext.w\t%0,%1
    lw\t%0,%1"
@@ -1749,7 +1761,7 @@  (define_insn_and_split "*extend<SHORT:mode><SUPERQI:mode>2"
   [(set (match_operand:SUPERQI   0 "register_operand"     "=r,r")
 	(sign_extend:SUPERQI
 	    (match_operand:SHORT 1 "nonimmediate_operand" " r,m")))]
-  "!TARGET_ZBB && !TARGET_XTHEADBB"
+  "!TARGET_ZBB && !TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX"
   "@
    #
    l<SHORT:size>\t%0,%1"
diff --git a/gcc/config/riscv/thead.cc b/gcc/config/riscv/thead.cc
index be0cd7c1276..237d96ff4b7 100644
--- a/gcc/config/riscv/thead.cc
+++ b/gcc/config/riscv/thead.cc
@@ -25,11 +25,16 @@ 
 #include "coretypes.h"
 #include "target.h"
 #include "backend.h"
+#include "tree.h"
 #include "rtl.h"
+#include "explow.h"
 #include "memmodel.h"
 #include "emit-rtl.h"
+#include "optabs.h"
 #include "poly-int.h"
 #include "output.h"
+#include "regs.h"
+#include "riscv-protos.h"
 
 /* If MEM is in the form of "base+offset", extract the two parts
    of address and set to BASE and OFFSET, otherwise return false
@@ -430,3 +435,450 @@  th_mempair_save_restore_regs (rtx operands[4], bool load_p,
   else
     th_mempair_save_regs (operands);
 }
+
+/* Return true if X can be represented as signed immediate of NBITS bits.
+   The immediate is assumed to be shifted by LSHAMT bits left.  */
+
+static bool
+valid_signed_immediate (rtx x, unsigned nbits, unsigned lshamt)
+{
+  if (GET_CODE (x) != CONST_INT)
+    return false;
+
+  HOST_WIDE_INT v = INTVAL (x);
+
+  HOST_WIDE_INT vunshifted = v >> lshamt;
+
+  /* Make sure we did not shift out any bits.  */
+  if (vunshifted << lshamt != v)
+    return false;
+
+  unsigned HOST_WIDE_INT imm_reach = 1LL << nbits;
+  return ((unsigned HOST_WIDE_INT) vunshifted + imm_reach/2 < imm_reach);
+}
+
+/* Return the address RTX of a move to/from memory
+   instruction.  */
+
+static rtx
+th_get_move_mem_addr (rtx dest, rtx src, bool load)
+{
+  rtx mem;
+
+  if (load)
+    mem = src;
+  else
+    mem = dest;
+
+  gcc_assert (GET_CODE (mem) == MEM);
+  return XEXP (mem, 0);
+}
+
+/* Return true if X is a valid address for T-Head's memory addressing modes
+   with pre/post modification for machine mode MODE.
+   If it is, fill in INFO appropriately (if non-NULL).
+   If STRICT_P is true then REG_OK_STRICT is in effect.  */
+
+static bool
+th_memidx_classify_address_modify (struct riscv_address_info *info, rtx x,
+				   machine_mode mode, bool strict_p)
+{
+  if (!TARGET_XTHEADMEMIDX)
+    return false;
+
+  if (!TARGET_64BIT && mode == DImode)
+    return false;
+
+  if (!(INTEGRAL_MODE_P (mode) && GET_MODE_SIZE (mode).to_constant () <= 8))
+    return false;
+
+  if (GET_CODE (x) != POST_MODIFY
+      && GET_CODE (x) != PRE_MODIFY)
+    return false;
+
+  rtx reg = XEXP (x, 0);
+  rtx exp = XEXP (x, 1);
+  rtx expreg = XEXP (exp, 0);
+  rtx expoff = XEXP (exp, 1);
+
+  if (GET_CODE (exp) != PLUS
+      || !rtx_equal_p (expreg, reg)
+      || !CONST_INT_P (expoff)
+      || !riscv_valid_base_register_p (reg, mode, strict_p))
+    return false;
+
+  /* The offset is calculated as (sign_extend(imm5) << imm2)  */
+  const int shamt_bits = 2;
+  for (int shamt = 0; shamt < (1 << shamt_bits); shamt++)
+    {
+      const int nbits = 5;
+      if (valid_signed_immediate (expoff, nbits, shamt))
+	{
+	  if (info)
+	    {
+	      info->type = ADDRESS_REG_WB;
+	      info->reg = reg;
+	      info->offset = expoff;
+	      info->shift = shamt;
+	    }
+	  return true;
+	}
+    }
+
+  return false;
+}
+
+/* Return TRUE if X is a MEM with a legitimate modify address.  */
+
+bool
+th_memidx_legitimate_modify_p (rtx x)
+{
+  if (!MEM_P (x))
+    return false;
+
+  /* Get the mode from the MEM and unpack it.  */
+  machine_mode mode = GET_MODE (x);
+  x = XEXP (x, 0);
+
+  return th_memidx_classify_address_modify (NULL, x, mode, reload_completed);
+}
+
+/* Return TRUE if X is a MEM with a legitimate modify address
+   and the address is POST_MODIFY (if POST is true) or a PRE_MODIFY
+   (otherwise).  */
+
+bool
+th_memidx_legitimate_modify_p (rtx x, bool post)
+{
+  if (!th_memidx_legitimate_modify_p (x))
+    return false;
+
+  /* Unpack the MEM and check the code.  */
+  x = XEXP (x, 0);
+  if (post)
+    return GET_CODE (x) == POST_MODIFY;
+  else
+    return GET_CODE (x) == PRE_MODIFY;
+}
+
+/* Provide a buffer for a th.lXia/th.lXib/th.sXia/th.sXib instruction
+   for the given MODE. If LOAD is true, a load instruction will be
+   provided (otherwise, a store instruction). If X is not suitable
+   return NULL.  */
+
+static const char *
+th_memidx_output_modify (rtx dest, rtx src, machine_mode mode, bool load)
+{
+  char format[24];
+  rtx output_operands[2];
+  rtx x = th_get_move_mem_addr (dest, src, load);
+
+  /* Validate x.  */
+  if (!th_memidx_classify_address_modify (NULL, x, mode, reload_completed))
+    return NULL;
+
+  int index = exact_log2 (GET_MODE_SIZE (mode).to_constant ());
+  bool post = GET_CODE (x) == POST_MODIFY;
+
+  const char *const insn[][4] = {
+    {
+      "th.sbi%s\t%%z1,%%0",
+      "th.shi%s\t%%z1,%%0",
+      "th.swi%s\t%%z1,%%0",
+      "th.sdi%s\t%%z1,%%0"
+    },
+    {
+      "th.lbui%s\t%%0,%%1",
+      "th.lhui%s\t%%0,%%1",
+      "th.lwi%s\t%%0,%%1",
+      "th.ldi%s\t%%0,%%1"
+    }
+  };
+
+  snprintf (format, sizeof (format), insn[load][index], post ? "a" : "b");
+  output_operands[0] = dest;
+  output_operands[1] = src;
+  output_asm_insn (format, output_operands);
+  return "";
+}
+
+static bool
+is_memidx_mode (machine_mode mode)
+{
+  if (mode == QImode || mode == HImode || mode == SImode)
+    return true;
+
+  if (mode == DImode && TARGET_64BIT)
+    return true;
+
+  return false;
+}
+
+/* Return true if X is a valid address for T-Head's memory addressing modes
+   with scaled register offsets for machine mode MODE.
+   If it is, fill in INFO appropriately (if non-NULL).
+   If STRICT_P is true then REG_OK_STRICT is in effect.  */
+
+static bool
+th_memidx_classify_address_index (struct riscv_address_info *info, rtx x,
+				  machine_mode mode, bool strict_p)
+{
+  /* Ensure that the mode is supported.  */
+  if (!(TARGET_XTHEADMEMIDX && is_memidx_mode (mode)))
+    return false;
+
+  if (GET_CODE (x) != PLUS)
+    return false;
+
+  rtx reg = XEXP (x, 0);
+  enum riscv_address_type type;
+  rtx offset = XEXP (x, 1);
+  int shift;
+
+  if (!riscv_valid_base_register_p (reg, mode, strict_p))
+    return false;
+
+  /* (reg:X) */
+  if (REG_P (offset)
+      && GET_MODE (offset) == Xmode)
+    {
+      type = ADDRESS_REG_REG;
+      shift = 0;
+      offset = offset;
+    }
+  /* (zero_extend:DI (reg:SI)) */
+  else if (GET_CODE (offset) == ZERO_EXTEND
+	   && GET_MODE (offset) == DImode
+	   && GET_MODE (XEXP (offset, 0)) == SImode)
+    {
+      type = ADDRESS_REG_UREG;
+      shift = 0;
+      offset = XEXP (offset, 0);
+    }
+  /* (ashift:X (reg:X) (const_int shift)) */
+  else if (GET_CODE (offset) == ASHIFT
+	   && GET_MODE (offset) == Xmode
+	   && REG_P (XEXP (offset, 0))
+	   && GET_MODE (XEXP (offset, 0)) == Xmode
+	   && CONST_INT_P (XEXP (offset, 1))
+	   && IN_RANGE (INTVAL (XEXP (offset, 1)), 0, 3))
+    {
+      type = ADDRESS_REG_REG;
+      shift = INTVAL (XEXP (offset, 1));
+      offset = XEXP (offset, 0);
+    }
+  /* (ashift:DI (zero_extend:DI (reg:SI)) (const_int shift)) */
+  else if (GET_CODE (offset) == ASHIFT
+	   && GET_MODE (offset) == DImode
+	   && GET_CODE (XEXP (offset, 0)) == ZERO_EXTEND
+	   && GET_MODE (XEXP (offset, 0)) == DImode
+	   && GET_MODE (XEXP (XEXP (offset, 0), 0)) == SImode
+	   && CONST_INT_P (XEXP (offset, 1))
+	   && IN_RANGE(INTVAL (XEXP (offset, 1)), 0, 3))
+    {
+      type = ADDRESS_REG_UREG;
+      shift = INTVAL (XEXP (offset, 1));
+      offset = XEXP (XEXP (offset, 0), 0);
+    }
+  else
+    return false;
+
+  if (!strict_p && GET_CODE (offset) == SUBREG)
+    offset = SUBREG_REG (offset);
+
+  if (!REG_P (offset)
+      || !riscv_regno_mode_ok_for_base_p (REGNO (offset), mode, strict_p))
+    return false;
+
+  if (info)
+    {
+      info->reg = reg;
+      info->type = type;
+      info->offset = offset;
+      info->shift = shift;
+    }
+  return true;
+}
+
+/* Return TRUE if X is a MEM with a legitimate indexed address.  */
+
+bool
+th_memidx_legitimate_index_p (rtx x)
+{
+  if (!MEM_P (x))
+    return false;
+
+  /* Get the mode from the MEM and unpack it.  */
+  machine_mode mode = GET_MODE (x);
+  x = XEXP (x, 0);
+
+  return th_memidx_classify_address_index (NULL, x, mode, reload_completed);
+}
+
+/* Return TRUE if X is a MEM with a legitimate indexed address
+   and the offset register is zero-extended (if UINDEX is true)
+   or sign-extended (otherwise).  */
+
+bool
+th_memidx_legitimate_index_p (rtx x, bool uindex)
+{
+  if (!MEM_P (x))
+    return false;
+
+  /* Get the mode from the MEM and unpack it.  */
+  machine_mode mode = GET_MODE (x);
+  x = XEXP (x, 0);
+
+  struct riscv_address_info info;
+  if (!th_memidx_classify_address_index (&info, x, mode, reload_completed))
+    return false;
+
+  if (uindex)
+    return info.type == ADDRESS_REG_UREG;
+  else
+    return info.type == ADDRESS_REG_REG;
+}
+
+/* Provide a buffer for a th.lrX/th.lurX/th.srX/th.surX instruction
+   for the given MODE. If LOAD is true, a load instruction will be
+   provided (otherwise, a store instruction). If X is not suitable
+   return NULL.  */
+
+static const char *
+th_memidx_output_index (rtx dest, rtx src, machine_mode mode, bool load)
+{
+  struct riscv_address_info info;
+  char format[24];
+  rtx output_operands[2];
+  rtx x = th_get_move_mem_addr (dest, src, load);
+
+  /* Validate x.  */
+  if (!th_memidx_classify_address_index (&info, x, mode, reload_completed))
+    return NULL;
+
+  int index = exact_log2 (GET_MODE_SIZE (mode).to_constant ());
+  bool uindex = info.type == ADDRESS_REG_UREG;
+
+  const char *const insn[][4] = {
+    {
+      "th.s%srb\t%%z1,%%0",
+      "th.s%srh\t%%z1,%%0",
+      "th.s%srw\t%%z1,%%0",
+      "th.s%srd\t%%z1,%%0"
+    },
+    {
+      "th.l%srbu\t%%0,%%1",
+      "th.l%srhu\t%%0,%%1",
+      "th.l%srw\t%%0,%%1",
+      "th.l%srd\t%%0,%%1"
+    }
+  };
+
+  snprintf (format, sizeof (format), insn[load][index], uindex ? "u" : "");
+  output_operands[0] = dest;
+  output_operands[1] = src;
+  output_asm_insn (format, output_operands);
+  return "";
+}
+
+/* Return true if X is a valid address for T-Head's memory addressing modes
+   for machine mode MODE.  If it is, fill in INFO appropriately (if non-NULL).
+   If STRICT_P is true then REG_OK_STRICT is in effect.  */
+
+bool
+th_classify_address (struct riscv_address_info *info, rtx x,
+		     machine_mode mode, bool strict_p)
+{
+  switch (GET_CODE (x))
+    {
+    case PLUS:
+      if (th_memidx_classify_address_index (info, x, mode, strict_p))
+	return true;
+      break;
+
+    case POST_MODIFY:
+    case PRE_MODIFY:
+      if (th_memidx_classify_address_modify (info, x, mode, strict_p))
+	return true;
+      break;
+
+    default:
+      return false;
+  }
+
+    return false;
+}
+
+/* Provide a string containing a XTheadMemIdx instruction for the given
+   MODE from the provided SRC to the provided DEST.
+   A pointer to a NULL-terminated string containing the instruction will
+   be returned if a suitable instruction is available. Otherwise, this
+   function returns NULL.  */
+
+const char *
+th_output_move (rtx dest, rtx src)
+{
+  enum rtx_code dest_code, src_code;
+  machine_mode mode;
+  const char *insn = NULL;
+
+  dest_code = GET_CODE (dest);
+  src_code = GET_CODE (src);
+  mode = GET_MODE (dest);
+
+  if (!(mode == GET_MODE (src) || src == CONST0_RTX (mode)))
+    return NULL;
+
+  if (dest_code == REG && src_code == MEM)
+    {
+      if (GET_MODE_CLASS (mode) == MODE_INT)
+	{
+	  if ((insn = th_memidx_output_index (dest, src, mode, true)))
+	    return insn;
+	  if ((insn = th_memidx_output_modify (dest, src, mode, true)))
+	    return insn;
+	}
+    }
+  else if (dest_code == MEM && (src_code == REG || src == CONST0_RTX (mode)))
+    {
+      if (GET_MODE_CLASS (mode) == MODE_INT
+	  || src == CONST0_RTX (mode))
+	{
+	  if ((insn = th_memidx_output_index (dest, src, mode, false)))
+	    return insn;
+	  if ((insn = th_memidx_output_modify (dest, src, mode, false)))
+	    return insn;
+	}
+    }
+  return NULL;
+}
+
+/* Implement TARGET_PRINT_OPERAND_ADDRESS for XTheadMemIdx.  */
+
+bool
+th_print_operand_address (FILE *file, machine_mode mode, rtx x)
+{
+  struct riscv_address_info addr;
+
+  if (!th_classify_address (&addr, x, mode, reload_completed))
+    return false;
+
+  switch (addr.type)
+    {
+    case ADDRESS_REG_REG:
+    case ADDRESS_REG_UREG:
+      fprintf (file, "%s,%s,%u", reg_names[REGNO (addr.reg)],
+	       reg_names[REGNO (addr.offset)], addr.shift);
+      return true;
+
+    case ADDRESS_REG_WB:
+      fprintf (file, "(%s),%ld,%u", reg_names[REGNO (addr.reg)],
+	       INTVAL (addr.offset) >> addr.shift, addr.shift);
+	return true;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  gcc_unreachable ();
+}
diff --git a/gcc/config/riscv/thead.md b/gcc/config/riscv/thead.md
index 4bb731b843b..dfcb6d926ec 100644
--- a/gcc/config/riscv/thead.md
+++ b/gcc/config/riscv/thead.md
@@ -62,7 +62,7 @@  (define_insn "*extendhi<SUPERQI:mode>2_th_ext"
   [(set (match_operand:SUPERQI 0 "register_operand" "=r,r")
 	(sign_extend:SUPERQI
 	    (match_operand:HI 1 "nonimmediate_operand" "r,m")))]
-  "TARGET_XTHEADBB"
+  "TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX"
   "@
    th.ext\t%0,%1,15,0
    lh\t%0,%1"
@@ -73,7 +73,7 @@  (define_insn "*extendqi<SUPERQI:mode>2_th_ext"
   [(set (match_operand:SUPERQI 0 "register_operand" "=r,r")
 	(sign_extend:SUPERQI
 	    (match_operand:QI 1 "nonimmediate_operand" "r,m")))]
-  "TARGET_XTHEADBB"
+  "TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX"
   "@
    th.ext\t%0,%1,7,0
    lb\t%0,%1"
@@ -96,7 +96,7 @@  (define_insn "*th_extu<mode>4"
 (define_insn "*zero_extendsidi2_th_extu"
   [(set (match_operand:DI 0 "register_operand" "=r,r")
 	(zero_extend:DI (match_operand:SI 1 "nonimmediate_operand" "r,m")))]
-  "TARGET_64BIT && TARGET_XTHEADBB"
+  "TARGET_64BIT && TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX"
   "@
    th.extu\t%0,%1,31,0
    lwu\t%0,%1"
@@ -106,7 +106,7 @@  (define_insn "*zero_extendsidi2_th_extu"
 (define_insn "*zero_extendhi<GPR:mode>2_th_extu"
   [(set (match_operand:GPR 0 "register_operand" "=r,r")
 	(zero_extend:GPR (match_operand:HI 1 "nonimmediate_operand" "r,m")))]
-  "TARGET_XTHEADBB"
+  "TARGET_XTHEADBB && !TARGET_XTHEADMEMIDX"
   "@
    th.extu\t%0,%1,15,0
    lhu\t%0,%1"
@@ -387,4 +387,429 @@  (define_insn "*th_mempair_load_zero_extendsidi2"
    (set_attr "mode" "DI")
    (set_attr "length" "8")])
 
+;; XTheadMemIdx
+
+;; Help reload to add a displacement for the base register.
+;; In the case `zext(*(uN*)(base+(zext(rN)<<1)))` LRA splits
+;; off two new instructions: a) `new_base = base + disp`, and
+;; b) `index = zext(rN)<<1`.  The index calculation has no
+;; corresponding instruction pattern and needs this insn_and_split
+;; to recover.
+
+(define_insn_and_split "*th_memidx_operand"
+  [(set (match_operand:DI 0 "register_operand" "=r")
+     (ashift:DI
+       (zero_extend:DI (subreg:SI (match_operand:DI 1 "register_operand" "r") 0))
+       (match_operand 2 "const_int_operand" "n")))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX && lra_in_progress"
+  "#"
+  ""
+  [(set (match_dup 0) (zero_extend:DI (subreg:SI (match_dup 1) 0)))
+   (set (match_dup 0) (ashift:DI (match_dup 0) (match_dup 2)))]
+  ""
+  [(set_attr "type" "bitmanip")])
+
+(define_insn "*th_memidx_zero_extendqi<SUPERQI:mode>2"
+  [(set (match_operand:SUPERQI 0 "register_operand" "=r,r,r,r,r,r")
+	(zero_extend:SUPERQI
+	    (match_operand:QI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_XTHEADMEMIDX"
+  "@
+   andi\t%0,%1,0xff
+   th.lbuia\t%0,%1
+   th.lbuib\t%0,%1
+   th.lrbu\t%0,%1
+   th.lurbu\t%0,%1
+   lbu\t%0,%1"
+  [(set_attr "move_type" "andi,load,load,load,load,load")
+   (set_attr "mode" "<SUPERQI:MODE>")])
+
+(define_insn "*th_memidx_extendsidi2"
+  [(set (match_operand:DI 0 "register_operand" "=r,r,r,r,r,r")
+	(sign_extend:DI
+	    (match_operand:SI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX"
+  "@
+   sext.w\t%0,%1
+   th.lwia\t%0,%1
+   th.lwib\t%0,%1
+   th.lrw\t%0,%1
+   th.lurw\t%0,%1
+   lw\t%0,%1"
+  [(set_attr "move_type" "move,load,load,load,load,load")
+   (set_attr "mode" "DI")])
+
+;; XTheadMemIdx (without XTheadBb)
+
+(define_insn_and_split "*th_memidx_zero_extendsidi2"
+  [(set (match_operand:DI 0 "register_operand" "=r,r,r,r,r,r")
+	(zero_extend:DI
+	    (match_operand:SI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX && !TARGET_XTHEADBB"
+  "@
+   #
+   th.lwuia\t%0,%1
+   th.lwuib\t%0,%1
+   th.lrwu\t%0,%1
+   th.lurwu\t%0,%1
+   lwu\t%0,%1"
+  "&& reload_completed
+   && REG_P (operands[1])
+   && !paradoxical_subreg_p (operands[0])"
+  [(set (match_dup 0)
+	(ashift:DI (match_dup 1) (const_int 32)))
+   (set (match_dup 0)
+	(lshiftrt:DI (match_dup 0) (const_int 32)))]
+  { operands[1] = gen_lowpart (DImode, operands[1]); }
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "DI")])
+
+(define_insn_and_split "*th_memidx_zero_extendhi<GPR:mode>2"
+  [(set (match_operand:GPR 0 "register_operand" "=r,r,r,r,r,r")
+	(zero_extend:GPR
+	    (match_operand:HI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_XTHEADMEMIDX && !TARGET_XTHEADBB"
+  "@
+   #
+   th.lhuia\t%0,%1
+   th.lhuib\t%0,%1
+   th.lrhu\t%0,%1
+   th.lurhu\t%0,%1
+   lhu\t%0,%1"
+  "&& reload_completed
+   && REG_P (operands[1])
+   && !paradoxical_subreg_p (operands[0])"
+  [(set (match_dup 0)
+	(ashift:GPR (match_dup 1) (match_dup 2)))
+   (set (match_dup 0)
+	(lshiftrt:GPR (match_dup 0) (match_dup 2)))]
+  {
+    operands[1] = gen_lowpart (<GPR:MODE>mode, operands[1]);
+    operands[2] = GEN_INT(GET_MODE_BITSIZE(<GPR:MODE>mode) - 16);
+  }
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "<GPR:MODE>")])
+
+(define_insn_and_split "*th_memidx_extend<SHORT:mode><SUPERQI:mode>2"
+  [(set (match_operand:SUPERQI 0 "register_operand" "=r,r,r,r,r,r")
+	(sign_extend:SUPERQI
+	    (match_operand:SHORT 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_XTHEADMEMIDX && !TARGET_XTHEADBB"
+  "@
+   #
+   th.l<SHORT:size>ia\t%0,%1
+   th.l<SHORT:size>ib\t%0,%1
+   th.lr<SHORT:size>\t%0,%1
+   th.lur<SHORT:size>\t%0,%1
+   l<SHORT:size>\t%0,%1"
+  "&& reload_completed
+   && REG_P (operands[1])
+   && !paradoxical_subreg_p (operands[0])"
+  [(set (match_dup 0) (ashift:SI (match_dup 1) (match_dup 2)))
+   (set (match_dup 0) (ashiftrt:SI (match_dup 0) (match_dup 2)))]
+{
+  operands[0] = gen_lowpart (SImode, operands[0]);
+  operands[1] = gen_lowpart (SImode, operands[1]);
+  operands[2] = GEN_INT (GET_MODE_BITSIZE (SImode)
+			 - GET_MODE_BITSIZE (<SHORT:MODE>mode));
+}
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "SI")])
+
+;; XTheadMemIdx (with XTheadBb)
+
+(define_insn "*th_memidx_bb_zero_extendsidi2"
+  [(set (match_operand:DI 0 "register_operand" "=r,r,r,r,r,r")
+	(zero_extend:DI
+	    (match_operand:SI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX && TARGET_XTHEADBB"
+  "@
+   th.extu\t%0,%1,31,0
+   th.lwuia\t%0,%1
+   th.lwuib\t%0,%1
+   th.lrwu\t%0,%1
+   th.lurwu\t%0,%1
+   lwu\t%0,%1"
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "DI")])
+
+(define_insn "*th_memidx_bb_zero_extendhi<GPR:mode>2"
+  [(set (match_operand:GPR 0 "register_operand" "=r,r,r,r,r,r")
+	(zero_extend:GPR
+	    (match_operand:HI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_XTHEADMEMIDX && TARGET_XTHEADBB"
+  "@
+   th.extu\t%0,%1,15,0
+   th.lhuia\t%0,%1
+   th.lhuib\t%0,%1
+   th.lrhu\t%0,%1
+   th.lurhu\t%0,%1
+   lhu\t%0,%1"
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "<GPR:MODE>")])
+
+(define_insn "*th_memidx_bb_extendhi<GPR:mode>2"
+  [(set (match_operand:GPR 0 "register_operand" "=r,r,r,r,r,r")
+	(sign_extend:GPR
+	    (match_operand:HI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_XTHEADMEMIDX && TARGET_XTHEADBB"
+  "@
+   th.ext\t%0,%1,15,0
+   th.lhia\t%0,%1
+   th.lhib\t%0,%1
+   th.lrh\t%0,%1
+   th.lurh\t%0,%1
+   lh\t%0,%1"
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "<GPR:MODE>")])
+
+(define_insn "*th_memidx_bb_extendqi<SUPERQI:mode>2"
+  [(set (match_operand:SUPERQI 0 "register_operand" "=r,r,r,r,r,r")
+	(sign_extend:SUPERQI
+	    (match_operand:QI 1 "nonimmediate_operand"
+         " r,th_m_mia,th_m_mib,th_m_mir,th_m_miu,m")))]
+  "TARGET_XTHEADMEMIDX && TARGET_XTHEADBB"
+  "@
+   th.ext\t%0,%1,7,0
+   th.lbia\t%0,%1
+   th.lbib\t%0,%1
+   th.lrb\t%0,%1
+   th.lurb\t%0,%1
+   lb\t%0,%1"
+  [(set_attr "move_type" "shift_shift,load,load,load,load,load")
+   (set_attr "mode" "<SUPERQI:MODE>")])
+
+(define_mode_iterator TH_M_ANYI [(QI "TARGET_XTHEADMEMIDX")
+                                 (HI "TARGET_XTHEADMEMIDX")
+                                 (SI "TARGET_XTHEADMEMIDX")
+                                 (DI "TARGET_64BIT && TARGET_XTHEADMEMIDX")])
+
+;; All non-extension modes that are supported by XTheadMemIdx
+(define_mode_iterator TH_M_NOEXTI [(SI "!TARGET_64BIT && TARGET_XTHEADMEMIDX")
+                                   (DI "TARGET_64BIT && TARGET_XTHEADMEMIDX")])
+
+;; XTheadMemIdx optimizations
+;; All optimizations attempt to improve the operand utilization of
+;; XTheadMemIdx instructions, where one sign or zero extended
+;; register-index-operand can be shifted left by a 2-bit immediate.
+;;
+;; The basic idea is the following optimization:
+;; (set (reg 0) (op (reg 1) (imm 2)))
+;; (set (reg 3) (mem (plus (reg 0) (reg 4)))
+;; ==>
+;; (set (reg 3) (mem (plus (reg 4) (op2 (reg 1) (imm 2))))
+;; This optimization only valid if (reg 0) has no further uses.
+;;
+;; The three-instruction case is as follows:
+;; (set (reg 0) (op1 (reg 1) (imm 2)))
+;; (set (reg 3) (op2 (reg 0) (imm 4)))
+;; (set (reg 5) (mem (plus (reg 3) (reg 6)))
+;; ==>
+;; (set (reg 5) (mem (plus (reg 6) (op2 (reg 1) (imm 2/4)))))
+;; This optimization is only valid if (reg 0) and (reg 3) have no further uses.
+;;
+;; The optimization cases are:
+;; I) fold 2-bit ashift of register offset into mem-plus RTX
+;; US) fold 32-bit zero-extended (shift) offset into mem-plus
+;; UZ) fold 32-bit zero-extended (zext) offset into mem-plus
+;;
+;; The first optimization case is targeting the th.lr<MODE> instructions.
+;; The other optimization cases are targeting the th.lur<MODE> instructions
+;; and have to consider two forms of zero-extensions:
+;; - ashift-32 + lshiftrt-{29..32} if there are no zero-extension instructions.
+;;   Left-shift amounts of 29..31 indicate a left-shifted zero-extended value.
+;; - zero-extend32 if there are zero-extension instructions (XTheadBb or Zbb).
+;;
+;; We always have three peephole passes per optimization case:
+;; a) no-extended (X) word-load
+;; b) any-extend (SUBX) word-load
+;; c) store
+;;
+;; Note, that SHIFTs will be converted to MULTs during combine.
+
+(define_insn_and_split "*th_memidx_I_a"
+  [(set (match_operand:TH_M_NOEXTI 0 "register_operand" "=r")
+        (mem:TH_M_NOEXTI (plus:X
+          (mult:X (match_operand:X 1 "register_operand" "r")
+                  (match_operand:QI 2 "immediate_operand" "i"))
+          (match_operand:X 3 "register_operand" "r"))))]
+  "TARGET_XTHEADMEMIDX
+   && CONST_INT_P (operands[2])
+   && pow2p_hwi (INTVAL (operands[2]))
+   && IN_RANGE (exact_log2 (INTVAL (operands[2])), 1, 3)"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+        (mem:TH_M_NOEXTI (plus:X
+          (match_dup 3)
+          (ashift:X (match_dup 1) (match_dup 2)))))]
+  { operands[2] = GEN_INT (exact_log2 (INTVAL (operands [2])));
+  }
+)
+
+(define_insn_and_split "*th_memidx_I_b"
+  [(set (match_operand:X 0 "register_operand" "=r")
+        (any_extend:X (mem:SUBX (plus:X
+          (mult:X (match_operand:X 1 "register_operand" "r")
+                  (match_operand:QI 2 "immediate_operand" "i"))
+          (match_operand:X 3 "register_operand" "r")))))]
+  "TARGET_XTHEADMEMIDX
+   && CONST_INT_P (operands[2])
+   && pow2p_hwi (INTVAL (operands[2]))
+   && IN_RANGE (exact_log2 (INTVAL (operands[2])), 1, 3)"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+        (any_extend:X (mem:SUBX (plus:X
+          (match_dup 3)
+          (ashift:X (match_dup 1) (match_dup 2))))))]
+  { operands[2] = GEN_INT (exact_log2 (INTVAL (operands [2])));
+  }
+)
+
+(define_insn_and_split "*th_memidx_I_c"
+  [(set (mem:TH_M_ANYI (plus:X
+          (mult:X (match_operand:X 1 "register_operand" "r")
+                  (match_operand:QI 2 "immediate_operand" "i"))
+          (match_operand:X 3 "register_operand" "r")))
+        (match_operand:TH_M_ANYI 0 "register_operand" "r"))]
+  "TARGET_XTHEADMEMIDX
+   && CONST_INT_P (operands[2])
+   && pow2p_hwi (INTVAL (operands[2]))
+   && IN_RANGE (exact_log2 (INTVAL (operands[2])), 1, 3)"
+  "#"
+  "&& 1"
+  [(set (mem:TH_M_ANYI (plus:X
+          (match_dup 3)
+          (ashift:X (match_dup 1) (match_dup 2))))
+        (match_dup 0))]
+  { operands[2] = GEN_INT (exact_log2 (INTVAL (operands [2])));
+  }
+)
+
+(define_insn_and_split "*th_memidx_US_a"
+  [(set (match_operand:TH_M_NOEXTI 0 "register_operand" "=r")
+        (mem:TH_M_NOEXTI (plus:DI
+          (and:DI
+            (mult:DI (match_operand:DI 1 "register_operand" "r")
+                     (match_operand:QI 2 "immediate_operand" "i"))
+            (match_operand:DI 3 "immediate_operand" "i"))
+          (match_operand:DI 4 "register_operand" "r"))))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX
+   && CONST_INT_P (operands[2])
+   && pow2p_hwi (INTVAL (operands[2]))
+   && IN_RANGE (exact_log2 (INTVAL (operands[2])), 1, 3)
+   && CONST_INT_P (operands[3])
+   && (INTVAL (operands[3]) >> exact_log2 (INTVAL (operands[2]))) == 0xffffffff"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+        (mem:TH_M_NOEXTI (plus:DI
+          (match_dup 4)
+          (ashift:DI (zero_extend:DI (match_dup 1)) (match_dup 2)))))]
+  { operands[1] = gen_lowpart (SImode, operands[1]);
+    operands[2] = GEN_INT (exact_log2 (INTVAL (operands [2])));
+  }
+)
+
+(define_insn_and_split "*th_memidx_US_b"
+  [(set (match_operand:X 0 "register_operand" "=r")
+        (any_extend:X (mem:SUBX (plus:DI
+          (and:DI
+            (mult:DI (match_operand:DI 1 "register_operand" "r")
+                     (match_operand:QI 2 "immediate_operand" "i"))
+            (match_operand:DI 3 "immediate_operand" "i"))
+          (match_operand:DI 4 "register_operand" "r")))))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX
+   && CONST_INT_P (operands[2])
+   && pow2p_hwi (INTVAL (operands[2]))
+   && IN_RANGE (exact_log2 (INTVAL (operands[2])), 1, 3)
+   && CONST_INT_P (operands[3])
+   && (INTVAL (operands[3]) >> exact_log2 (INTVAL (operands[2]))) == 0xffffffff"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+        (any_extend:X (mem:SUBX (plus:DI
+          (match_dup 4)
+          (ashift:DI (zero_extend:DI (match_dup 1)) (match_dup 2))))))]
+  { operands[1] = gen_lowpart (SImode, operands[1]);
+    operands[2] = GEN_INT (exact_log2 (INTVAL (operands [2])));
+  }
+)
+
+(define_insn_and_split "*th_memidx_US_c"
+  [(set (mem:TH_M_ANYI (plus:DI
+          (and:DI
+            (mult:DI (match_operand:DI 1 "register_operand" "r")
+                     (match_operand:QI 2 "immediate_operand" "i"))
+            (match_operand:DI 3 "immediate_operand" "i"))
+          (match_operand:DI 4 "register_operand" "r")))
+        (match_operand:TH_M_ANYI 0 "register_operand" "r"))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX
+   && CONST_INT_P (operands[2])
+   && pow2p_hwi (INTVAL (operands[2]))
+   && IN_RANGE (exact_log2 (INTVAL (operands[2])), 1, 3)
+   && CONST_INT_P (operands[3])
+   && (INTVAL (operands[3]) >> exact_log2 (INTVAL (operands[2]))) == 0xffffffff"
+  "#"
+  "&& 1"
+  [(set (mem:TH_M_ANYI (plus:DI
+          (match_dup 4)
+          (ashift:DI (zero_extend:DI (match_dup 1)) (match_dup 2))))
+        (match_dup 0))]
+  { operands[1] = gen_lowpart (SImode, operands[1]);
+    operands[2] = GEN_INT (exact_log2 (INTVAL (operands [2])));
+  }
+)
+
+(define_insn_and_split "*th_memidx_UZ_a"
+  [(set (match_operand:TH_M_NOEXTI 0 "register_operand" "=r")
+        (mem:TH_M_NOEXTI (plus:DI
+          (zero_extend:DI (match_operand:SI 1 "register_operand" "r"))
+          (match_operand:DI 2 "register_operand" "r"))))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+        (mem:TH_M_NOEXTI (plus:DI
+          (match_dup 2)
+          (zero_extend:DI (match_dup 1)))))]
+)
+
+(define_insn_and_split "*th_memidx_UZ_b"
+  [(set (match_operand:X 0 "register_operand" "=r")
+        (any_extend:X (mem:SUBX (plus:DI
+          (zero_extend:DI (match_operand:SI 1 "register_operand" "r"))
+          (match_operand:DI 2 "register_operand" "r")))))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+        (any_extend:X (mem:SUBX (plus:DI
+          (match_dup 2)
+          (zero_extend:DI (match_dup 1))))))]
+)
+
+(define_insn_and_split "*th_memidx_UZ_c"
+  [(set (mem:TH_M_ANYI (plus:DI
+          (zero_extend:DI (match_operand:SI 1 "register_operand" "r"))
+          (match_operand:DI 2 "register_operand" "r")))
+        (match_operand:TH_M_ANYI 0 "register_operand" "r"))]
+  "TARGET_64BIT && TARGET_XTHEADMEMIDX"
+  "#"
+  "&& 1"
+  [(set (mem:TH_M_ANYI (plus:DI
+          (match_dup 2)
+          (zero_extend:DI (match_dup 1))))
+        (match_dup 0))]
+)
+
 (include "thead-peephole.md")
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-helpers.h b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-helpers.h
new file mode 100644
index 00000000000..a97f08c5cc1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-helpers.h
@@ -0,0 +1,152 @@ 
+#ifndef XTHEADMEMIDX_HELPERS_H
+#define XTHEADMEMIDX_HELPERS_H
+
+#include <stdint.h>
+
+#define intX_t long
+#define uintX_t unsigned long
+
+#define PRE_DEC_LOAD(T, N)						\
+  void									\
+  T ## _pre_dec_load_ ## N (T *p)					\
+  {									\
+    extern void f ## T ## N (T*, uintX_t);				\
+    p = p - N;								\
+    T x = *p;								\
+    f ## T ## N (p, x);							\
+  }
+
+#define PRE_INC_LOAD(T, N)						\
+  void									\
+  T ## _pre_inc_load_ ## N (T *p)					\
+  {									\
+    extern void f ## T ## N (T*, uintX_t);				\
+    p = p + N;								\
+    T x = *p;								\
+    f ## T ## N (p, x);							\
+  }
+
+#define POST_DEC_LOAD(T, N)						\
+  void									\
+  T ## _post_dec_load_ ## N (T *p)					\
+  {									\
+    extern void f ## T ## N (T*, uintX_t);				\
+    T x = *p;								\
+    p = p - N;								\
+    f ## T ## N (p, x);							\
+  }
+
+#define POST_INC_LOAD(T,N)						\
+  void									\
+  T ## _post_inc_load_ ## N (T *p)					\
+  {									\
+    extern void f ## T ## N (T*,uintX_t);				\
+    T x = *p;								\
+    p = p + N;								\
+    f ## T ## N (p, x);							\
+  }
+
+#define PRE_DEC_STORE(T, N)						\
+  T *									\
+  T ## _pre_dec_store_ ## N (T *p, T v)					\
+  {									\
+    p = p - N;								\
+    *p = v;								\
+    return p;								\
+  }
+
+#define PRE_INC_STORE(T, N)						\
+  T *									\
+  T ## _pre_inc_store_ ## N (T *p, T v)					\
+  {									\
+    p = p + N;								\
+    *p = v;								\
+    return p;								\
+  }
+
+#define POST_DEC_STORE(T, N)						\
+  T *									\
+  T ## _post_dec_store_ ## N (T *p, T v)				\
+  {									\
+    *p = v;								\
+    p = p - N;								\
+    return p;								\
+  }
+
+#define POST_INC_STORE(T, N)						\
+  T *									\
+  T ## _post_inc_store_ ## N (T *p, T v)				\
+  {									\
+    *p = v;								\
+    p = p + N;								\
+    return p;								\
+  }
+
+#define LR_REG_IMM(T, IMM)						\
+  intX_t								\
+  lr_reg_imm_ ## T ## _ ## IMM (intX_t rs1, intX_t rs2)			\
+  {									\
+    return *(T*)(rs1 + (rs2 << IMM));					\
+  }
+
+#define SR_REG_IMM(T, IMM)						\
+  void									\
+  sr_reg_imm_ ## T ## _ ## IMM (intX_t rs1, intX_t rs2, T val)		\
+  {									\
+    *(T*)(rs1 + (rs2 << IMM)) = val;					\
+  }
+
+#define LR_REG_IMM_UPD(T, IMM)						\
+  intX_t								\
+  lr_reg_imm_upd_ ## T ## _ ## IMM (intX_t *rs1, intX_t rs2)		\
+  {									\
+    *rs1 = *rs1 + (rs2 << IMM);						\
+    return *(T*)(*rs1);							\
+  }
+
+#define SR_REG_IMM_UPD(T, IMM)						\
+  void									\
+  sr_reg_imm_upd_ ## T ## _ ## IMM (intX_t *rs1, intX_t rs2, T val)	\
+  {									\
+    *rs1 = *rs1 + (rs2 << IMM);						\
+    *(T*)(*rs1) = val;	 						\
+  }
+
+#define LRU_REG_IMM(T, IMM)						\
+  intX_t								\
+  lru_reg_imm_ ## T ## IMM (intX_t rs1, intX_t rs2)			\
+  {									\
+    rs2 = (uint32_t)rs2;						\
+    return *(T*)(rs1 + (rs2 << IMM));					\
+  }
+
+#define SRU_REG_IMM(T, IMM)						\
+  void									\
+  sr_reg_imm_ ## T ## _ ## IMM (intX_t rs1, intX_t rs2, T val)		\
+  {									\
+    rs2 = (uint32_t)rs2;						\
+    *(T*)(rs1 + (rs2 << IMM)) = val;					\
+  }
+
+#define LRU_REG_IMM_UPD(T, IMM)						\
+  intX_t								\
+  lru_reg_imm_upd_ ## T ## IMM (intX_t rs1, intX_t *rs2)		\
+  {									\
+    uintX_t rs2_32 = (uint32_t)*rs2;					\
+    intX_t t = rs1 + (rs2_32 << IMM);					\
+    intX_t v = *(T*)t;							\
+    *rs2 = t;								\
+    return v;								\
+  }
+
+#define SRU_REG_IMM_UPD(T, IMM)						\
+  void									\
+  sr_reg_imm_upd_ ## T ## _ ## IMM (intX_t rs1, intX_t *rs2, T val)	\
+  {									\
+    uintX_t rs2_32 = (uint32_t)*rs2;					\
+    intX_t t = rs1 + (rs2_32 << IMM);					\
+    *(T*)t = val;							\
+    *rs2 = t;								\
+  }
+
+#endif /* XTHEADMEMIDX_HELPERS_H */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-update.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-update.c
new file mode 100644
index 00000000000..5bbf668597c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-update.c
@@ -0,0 +1,27 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LR_REG_IMM_UPD(int8_t, 0)
+LR_REG_IMM_UPD(uint8_t, 1)
+LR_REG_IMM_UPD(int16_t, 2)
+LR_REG_IMM_UPD(uint16_t, 3)
+LR_REG_IMM_UPD(int32_t, 0)
+#if __riscv_xlen == 64
+LR_REG_IMM_UPD(uint32_t, 1)
+LR_REG_IMM_UPD(int64_t, 2)
+#endif
+
+SR_REG_IMM_UPD(int8_t, 3)
+SR_REG_IMM_UPD(int16_t, 0)
+SR_REG_IMM_UPD(int32_t, 1)
+#if __riscv_xlen == 64
+SR_REG_IMM_UPD(int64_t, 2)
+#endif
+
+/* If the shifted value is used later, we cannot eliminate it.  */
+/* { dg-final { scan-assembler-times {\mslli\M} 5 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times {\mslli\M} 8 { target { rv64 } } } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb-update.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb-update.c
new file mode 100644
index 00000000000..cfa1d2e02a5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb-update.c
@@ -0,0 +1,27 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadbb_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadbb_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LR_REG_IMM_UPD(int8_t, 0)
+LR_REG_IMM_UPD(uint8_t, 1)
+LR_REG_IMM_UPD(int16_t, 2)
+LR_REG_IMM_UPD(uint16_t, 3)
+LR_REG_IMM_UPD(int32_t, 0)
+#if __riscv_xlen == 64
+LR_REG_IMM_UPD(uint32_t, 1)
+LR_REG_IMM_UPD(int64_t, 2)
+#endif
+
+SR_REG_IMM_UPD(int8_t, 3)
+SR_REG_IMM_UPD(int16_t, 0)
+SR_REG_IMM_UPD(int32_t, 1)
+#if __riscv_xlen == 64
+SR_REG_IMM_UPD(int64_t, 2)
+#endif
+
+/* If the shifted value is used later, we cannot eliminate it.  */
+/* { dg-final { scan-assembler-times {\mslli\M} 5 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times {\mslli\M} 8 { target { rv64 } } } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb.c
new file mode 100644
index 00000000000..7988fdf5d65
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index-xtheadbb.c
@@ -0,0 +1,36 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadbb_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadbb_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LR_REG_IMM(int8_t, 0)
+/* { dg-final { scan-assembler-times {\mth.lrb\t[^\n\r]*0\M} 1 } } */
+LR_REG_IMM(uint8_t, 1)
+/* { dg-final { scan-assembler-times {\mth.lrbu\t[^\n\r]*1\M} 1 } } */
+LR_REG_IMM(int16_t, 2)
+/* { dg-final { scan-assembler-times {\mth.lrh\t[^\n\r]*2\M} 1 } } */
+LR_REG_IMM(uint16_t, 3)
+/* { dg-final { scan-assembler-times {\mth.lrhu\t[^\n\r]*3\M} 1 } } */
+LR_REG_IMM(int32_t, 0)
+/* { dg-final { scan-assembler-times {\mth.lrw\t[^\n\r]*0\M} 1 } } */
+#if __riscv_xlen == 64
+LR_REG_IMM(uint32_t, 1)
+/* { dg-final { scan-assembler-times {\mth.lrwu\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+LR_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth.lrd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+SR_REG_IMM(int8_t, 3)
+/* { dg-final { scan-assembler-times {\mth.srb\t[^\n\r]*3\M} 1 } } */
+SR_REG_IMM(int16_t, 0)
+/* { dg-final { scan-assembler-times {\mth.srh\t[^\n\r]*0\M} 1 } } */
+SR_REG_IMM(int32_t, 1)
+/* { dg-final { scan-assembler-times {\mth.srw\t[^\n\r]*1\M} 1 } } */
+#if __riscv_xlen == 64
+SR_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth.srd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+/* { dg-final { scan-assembler-not {\mslli\M} } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index.c
new file mode 100644
index 00000000000..92bb0844958
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-index.c
@@ -0,0 +1,36 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LR_REG_IMM(int8_t, 0)
+/* { dg-final { scan-assembler-times {\mth.lrb\t[^\n\r]*0\M} 1 } } */
+LR_REG_IMM(uint8_t, 1)
+/* { dg-final { scan-assembler-times {\mth.lrbu\t[^\n\r]*1\M} 1 } } */
+LR_REG_IMM(int16_t, 2)
+/* { dg-final { scan-assembler-times {\mth.lrh\t[^\n\r]*2\M} 1 } } */
+LR_REG_IMM(uint16_t, 3)
+/* { dg-final { scan-assembler-times {\mth.lrhu\t[^\n\r]*3\M} 1 } } */
+LR_REG_IMM(int32_t, 0)
+/* { dg-final { scan-assembler-times {\mth.lrw\t[^\n\r]*0\M} 1 } } */
+#if __riscv_xlen == 64
+LR_REG_IMM(uint32_t, 1)
+/* { dg-final { scan-assembler-times {\mth.lrwu\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+LR_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth.lrd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+SR_REG_IMM(int8_t, 3)
+/* { dg-final { scan-assembler-times {\mth.srb\t[^\n\r]*3\M} 1 } } */
+SR_REG_IMM(int16_t, 0)
+/* { dg-final { scan-assembler-times {\mth.srh\t[^\n\r]*0\M} 1 } } */
+SR_REG_IMM(int32_t, 1)
+/* { dg-final { scan-assembler-times {\mth.srw\t[^\n\r]*1\M} 1 } } */
+#if __riscv_xlen == 64
+SR_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth.srd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+/* { dg-final { scan-assembler-not {\mslli\M} } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify-xtheadbb.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify-xtheadbb.c
new file mode 100644
index 00000000000..8430b8daadf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify-xtheadbb.c
@@ -0,0 +1,74 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" "-Os" "-Oz" } } */
+/* { dg-options "-march=rv64gc_xtheadbb_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadbb_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+/* We have a simm5 shifted by a imm2.
+   imm2  | range (simm5 << imm2)
+     0   |  -16..-1,0..15
+     1   |  -32..-2,0..30
+     2   |  -64..-4,0..60
+     3   | -128..-8,0..120  */
+
+POST_INC_LOAD(int8_t, 1)
+/* { dg-final { scan-assembler {\mth.lbia[^\n\r]*1,0\M} } } */
+PRE_DEC_LOAD(int8_t, 32)
+/* { dg-final { scan-assembler {\mth.lbib[^\n\r]*-16,1\M} } } */
+
+POST_DEC_LOAD(uint8_t, 1)
+/* { dg-final { scan-assembler {\mth.lbuia[^\n\r]*-1,0\M} } } */
+PRE_INC_LOAD(uint8_t, 32)
+/* { dg-final { scan-assembler {\mth.lbuib[^\n\r]*8,2\M} } } */
+
+POST_INC_LOAD(int16_t, 1)
+/* { dg-final { scan-assembler {\mth.lhia[^\n\r]*2,0\M} } } */
+POST_DEC_LOAD(int16_t, 64)
+/* { dg-final { scan-assembler {\mth.lhia[^\n\r]*-16,3\M} } } */
+
+POST_DEC_LOAD(uint16_t, 1)
+/* { dg-final { scan-assembler {\mth.lhuia[^\n\r]*-2,0\M} } } */
+POST_INC_LOAD(uint16_t, 60)
+/* { dg-final { scan-assembler {\mth.lhuia[^\n\r]*15,3\M} } } */
+
+POST_INC_LOAD(int32_t, 1)
+/* { dg-final { scan-assembler {\mth.lwia[^\n\r]*4,0\M} } } */
+PRE_DEC_LOAD(int32_t, 32)
+/* { dg-final { scan-assembler {\mth.lwib[^\n\r]*-16,3\M} } } */
+
+#if __riscv_xlen == 64
+POST_DEC_LOAD(uint32_t, 1)
+/* { dg-final { scan-assembler {\mth.lwuia[^\n\r]*-4,0\M} { target { rv64 } } } } */
+PRE_INC_LOAD(uint32_t, 15)
+/* { dg-final { scan-assembler {\mth.lwuib[^\n\r]*15,2\M} { target { rv64 } } } } */
+
+POST_INC_LOAD(int64_t, 1)
+/* { dg-final { scan-assembler {\mth.ldia[^\n\r]*8,0\M} { target { rv64 } } } } */
+PRE_DEC_LOAD(int64_t, 16)
+/* { dg-final { scan-assembler {\mth.ldib[^\n\r]*-16,3\M} { target { rv64 } } } } */
+#endif
+
+POST_DEC_STORE(int8_t, 1)
+/* { dg-final { scan-assembler {\mth.sbia[^\n\r]*-1,0\M} } } */
+PRE_INC_STORE(int8_t, 120)
+/* { dg-final { scan-assembler {\mth.sbib[^\n\r]*15,3\M} } } */
+
+POST_INC_STORE(int16_t, 1)
+/* { dg-final { scan-assembler {\mth.shia[^\n\r]*2,0\M} } } */
+PRE_DEC_STORE(int16_t, 64)
+/* { dg-final { scan-assembler {\mth.shib[^\n\r]*-16,3\M} } } */
+
+POST_DEC_STORE(int32_t, 1)
+/* { dg-final { scan-assembler {\mth.swia[^\n\r]*-4,0\M} } } */
+PRE_INC_STORE(int32_t, 2)
+/* { dg-final { scan-assembler {\mth.swib[^\n\r]*8,0\M} } } */
+
+#if __riscv_xlen == 64
+POST_INC_STORE(int64_t, 1)
+/* { dg-final { scan-assembler {\mth.sdia[^\n\r]*8,0\M} { target { rv64 } } } } */
+PRE_DEC_STORE(int64_t, 8)
+/* { dg-final { scan-assembler {\mth.sdib[^\n\r]*-16,2\M} { target { rv64 } } } } */
+#endif
+
+/* { dg-final { scan-assembler-not {\m\taddi\M} } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify.c
new file mode 100644
index 00000000000..0bcd78d8915
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-modify.c
@@ -0,0 +1,74 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" "-Os" "-Oz" } } */
+/* { dg-options "-march=rv64gc_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+/* We have a simm5 shifted by a imm2.
+   imm2  | range (simm5 << imm2)
+     0   |  -16..-1,0..15
+     1   |  -32..-2,0..30
+     2   |  -64..-4,0..60
+     3   | -128..-8,0..120  */
+
+POST_INC_LOAD(int8_t, 1)
+/* { dg-final { scan-assembler {\mth.lbia[^\n\r]*1,0\M} } } */
+PRE_DEC_LOAD(int8_t, 32)
+/* { dg-final { scan-assembler {\mth.lbib[^\n\r]*-16,1\M} } } */
+
+POST_DEC_LOAD(uint8_t, 1)
+/* { dg-final { scan-assembler {\mth.lbuia[^\n\r]*-1,0\M} } } */
+PRE_INC_LOAD(uint8_t, 32)
+/* { dg-final { scan-assembler {\mth.lbuib[^\n\r]*8,2\M} } } */
+
+POST_INC_LOAD(int16_t, 1)
+/* { dg-final { scan-assembler {\mth.lhia[^\n\r]*2,0\M} } } */
+POST_DEC_LOAD(int16_t, 64)
+/* { dg-final { scan-assembler {\mth.lhia[^\n\r]*-16,3\M} } } */
+
+POST_DEC_LOAD(uint16_t, 1)
+/* { dg-final { scan-assembler {\mth.lhuia[^\n\r]*-2,0\M} } } */
+POST_INC_LOAD(uint16_t, 60)
+/* { dg-final { scan-assembler {\mth.lhuia[^\n\r]*15,3\M} } } */
+
+POST_INC_LOAD(int32_t, 1)
+/* { dg-final { scan-assembler {\mth.lwia[^\n\r]*4,0\M} } } */
+PRE_DEC_LOAD(int32_t, 32)
+/* { dg-final { scan-assembler {\mth.lwib[^\n\r]*-16,3\M} } } */
+
+#if __riscv_xlen == 64
+POST_DEC_LOAD(uint32_t, 1)
+/* { dg-final { scan-assembler {\mth.lwuia[^\n\r]*-4,0\M} { target { rv64 } } } } */
+PRE_INC_LOAD(uint32_t, 15)
+/* { dg-final { scan-assembler {\mth.lwuib[^\n\r]*15,2\M} { target { rv64 } } } } */
+
+POST_INC_LOAD(int64_t, 1)
+/* { dg-final { scan-assembler {\mth.ldia[^\n\r]*8,0\M} { target { rv64 } } } } */
+PRE_DEC_LOAD(int64_t, 16)
+/* { dg-final { scan-assembler {\mth.ldib[^\n\r]*-16,3\M} { target { rv64 } } } } */
+#endif
+
+POST_DEC_STORE(int8_t, 1)
+/* { dg-final { scan-assembler {\mth.sbia[^\n\r]*-1,0\M} } } */
+PRE_INC_STORE(int8_t, 120)
+/* { dg-final { scan-assembler {\mth.sbib[^\n\r]*15,3\M} } } */
+
+POST_INC_STORE(int16_t, 1)
+/* { dg-final { scan-assembler {\mth.shia[^\n\r]*2,0\M} } } */
+PRE_DEC_STORE(int16_t, 64)
+/* { dg-final { scan-assembler {\mth.shib[^\n\r]*-16,3\M} } } */
+
+POST_DEC_STORE(int32_t, 1)
+/* { dg-final { scan-assembler {\mth.swia[^\n\r]*-4,0\M} } } */
+PRE_INC_STORE(int32_t, 2)
+/* { dg-final { scan-assembler {\mth.swib[^\n\r]*8,0\M} } } */
+
+#if __riscv_xlen == 64
+POST_INC_STORE(int64_t, 1)
+/* { dg-final { scan-assembler {\mth.sdia[^\n\r]*8,0\M} { target { rv64 } } } } */
+PRE_DEC_STORE(int64_t, 8)
+/* { dg-final { scan-assembler {\mth.sdib[^\n\r]*-16,2\M} { target { rv64 } } } } */
+#endif
+
+/* { dg-final { scan-assembler-not {\m\taddi\M} } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-update.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-update.c
new file mode 100644
index 00000000000..d3fd069459b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-update.c
@@ -0,0 +1,27 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" "-Os" "-Oz" } } */
+/* { dg-options "-march=rv64gc_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LRU_REG_IMM_UPD(int8_t, 0)
+LRU_REG_IMM_UPD(uint8_t, 1)
+LRU_REG_IMM_UPD(int16_t, 2)
+LRU_REG_IMM_UPD(uint16_t, 3)
+LRU_REG_IMM_UPD(int32_t, 0)
+#if __riscv_xlen == 64
+LRU_REG_IMM_UPD(uint32_t, 1)
+LRU_REG_IMM_UPD(int64_t, 2)
+#endif
+
+SRU_REG_IMM_UPD(int8_t, 3)
+SRU_REG_IMM_UPD(int16_t, 0)
+SRU_REG_IMM_UPD(int32_t, 1)
+#if __riscv_xlen == 64
+SRU_REG_IMM_UPD(int64_t, 2)
+#endif
+
+/* If the shifted value is used later, we cannot eliminate it.  */
+/* { dg-final { scan-assembler-times {\mslli\M} 5 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times {\mslli\M} 8 { target { rv64 } } } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb-update.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb-update.c
new file mode 100644
index 00000000000..ee0486a526e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb-update.c
@@ -0,0 +1,27 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadbb_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadbb_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LRU_REG_IMM_UPD(int8_t, 0)
+LRU_REG_IMM_UPD(uint8_t, 1)
+LRU_REG_IMM_UPD(int16_t, 2)
+LRU_REG_IMM_UPD(uint16_t, 3)
+LRU_REG_IMM_UPD(int32_t, 0)
+#if __riscv_xlen == 64
+LRU_REG_IMM_UPD(uint32_t, 1)
+LRU_REG_IMM_UPD(int64_t, 2)
+#endif
+
+SRU_REG_IMM_UPD(int8_t, 3)
+SRU_REG_IMM_UPD(int16_t, 0)
+SRU_REG_IMM_UPD(int32_t, 1)
+#if __riscv_xlen == 64
+SRU_REG_IMM_UPD(int64_t, 2)
+#endif
+
+/* If the shifted value is used later, we cannot eliminate it.  */
+/* { dg-final { scan-assembler-times {\mslli\M} 5 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times {\mslli\M} 8 { target { rv64 } } } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb.c
new file mode 100644
index 00000000000..ccabe99ae60
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex-xtheadbb.c
@@ -0,0 +1,44 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadbb_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadbb_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LRU_REG_IMM(int8_t, 0)
+/* { dg-final { scan-assembler-times {\mth.lurb\t[^\n\r]*0\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.lrb\t[^\n\r]*0\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(uint8_t, 1)
+/* { dg-final { scan-assembler-times {\mth.lurbu\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.lrbu\t[^\n\r]*1\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(int16_t, 2)
+/* { dg-final { scan-assembler-times {\mth.lurh\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.lrh\t[^\n\r]*2\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(uint16_t, 3)
+/* { dg-final { scan-assembler-times {\mth.lurhu\t[^\n\r]*3\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.lrhu\t[^\n\r]*3\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(int32_t, 0)
+/* { dg-final { scan-assembler-times {\mth.lurw\t[^\n\r]*0\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.lrw\t[^\n\r]*0\M} 1 { target { rv32 } } } } */
+#if __riscv_xlen == 64
+LRU_REG_IMM(uint32_t, 1)
+/* { dg-final { scan-assembler-times {\mth.lurwu\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+LRU_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth.lurd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+SRU_REG_IMM(int8_t, 3)
+/* { dg-final { scan-assembler-times {\mth.surb\t[^\n\r]*3\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.srb\t[^\n\r]*3\M} 1 { target { rv32 } } } } */
+SRU_REG_IMM(int16_t, 0)
+/* { dg-final { scan-assembler-times {\mth.surh\t[^\n\r]*0\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.srh\t[^\n\r]*0\M} 1 { target { rv32 } } } } */
+SRU_REG_IMM(int32_t, 1)
+/* { dg-final { scan-assembler-times {\mth.surw\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth.srw\t[^\n\r]*1\M} 1 { target { rv32 } } } } */
+#if __riscv_xlen == 64
+SRU_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth.surd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+/* { dg-final { scan-assembler-not {\mslli\M} } } */
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex.c b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex.c
new file mode 100644
index 00000000000..369ffb23ea4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmemidx-uindex.c
@@ -0,0 +1,44 @@ 
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_xtheadmemidx" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadmemidx" { target { rv32 } } } */
+
+#include "xtheadmemidx-helpers.h"
+
+LRU_REG_IMM(int8_t, 0)
+/* { dg-final { scan-assembler-times {\mth\.lurb\t[^\n\r]*0\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.lrb\t[^\n\r]*0\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(uint8_t, 1)
+/* { dg-final { scan-assembler-times {\mth\.lurbu\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.lrbu\t[^\n\r]*1\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(int16_t, 2)
+/* { dg-final { scan-assembler-times {\mth\.lurh\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.lrh\t[^\n\r]*2\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(uint16_t, 3)
+/* { dg-final { scan-assembler-times {\mth\.lurhu\t[^\n\r]*3\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.lrhu\t[^\n\r]*3\M} 1 { target { rv32 } } } } */
+LRU_REG_IMM(int32_t, 0)
+/* { dg-final { scan-assembler-times {\mth\.lurw\t[^\n\r]*0\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.lrw\t[^\n\r]*0\M} 1 { target { rv32 } } } } */
+#if __riscv_xlen == 64
+LRU_REG_IMM(uint32_t, 1)
+/* { dg-final { scan-assembler-times {\mth\.lurwu\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+LRU_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth\.lurd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+SRU_REG_IMM(int8_t, 3)
+/* { dg-final { scan-assembler-times {\mth\.surb\t[^\n\r]*3\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.srb\t[^\n\r]*3\M} 1 { target { rv32 } } } } */
+SRU_REG_IMM(int16_t, 0)
+/* { dg-final { scan-assembler-times {\mth\.surh\t[^\n\r]*0\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.srh\t[^\n\r]*0\M} 1 { target { rv32 } } } } */
+SRU_REG_IMM(int32_t, 1)
+/* { dg-final { scan-assembler-times {\mth\.surw\t[^\n\r]*1\M} 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times {\mth\.srw\t[^\n\r]*1\M} 1 { target { rv32 } } } } */
+#if __riscv_xlen == 64
+SRU_REG_IMM(int64_t, 2)
+/* { dg-final { scan-assembler-times {\mth\.surd\t[^\n\r]*2\M} 1 { target { rv64 } } } } */
+#endif
+
+/* { dg-final { scan-assembler-not {\mslli\M} } } */