diff mbox series

[V2] Power10: Add options to disable load and store vector pair.

Message ID ZU60wCU3w1RkyOY/@cowardly-lion.the-meissners.org
State Unresolved
Headers
Series [V2] Power10: Add options to disable load and store vector pair. |

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Commit Message

Michael Meissner Nov. 10, 2023, 10:54 p.m. UTC 
  This is version 2 of the patch to add -mno-load-vector-pair and
-mno-store-vector-pair undocumented tuning switches.

The differences between the first version of the patch and this version is that
I added explicit RTL abi attributes for when the compiler can generate the load
vector pair and store vector pair instructions.  By having this attribute, the
movoo insn has separate alternatives for when we generate the instruction and
when we want to split the instruction into 2 separate vector loads or stores.

In the first version of the patch, I had previously provided built-in functions
that would always generate load vector pair and store vector pair instructions
even if these instructions are normally disabled.  I found these built-ins
weren't specified like the other vector pair built-ins, and I didn't include
documentation for the built-in functions.  If we want such built-in functions,
we can add them as a separate patch later.

In addition, since both versions of the patch adds #pragma target and attribute
support to change the results for individual functions, we can select on a
function by function basis what the defaults for load/store vector pair is.

The original text for the patch is:

In working on some future patches that involve utilizing vector pair
instructions, I wanted to be able to tune my program to enable or disable using
the vector pair load or store operations while still keeping the other
operations on the vector pair.

This patch adds two undocumented tuning options.  The -mno-load-vector-pair
option would tell GCC to generate two load vector instructions instead of a
single load vector pair.  The -mno-store-vector-pair option would tell GCC to
generate two store vector instructions instead of a single store vector pair.

If either -mno-load-vector-pair is used, GCC will not generate the indexed
stxvpx instruction.  Similarly if -mno-store-vector-pair is used, GCC will not
generate the indexed lxvpx instruction.  The reason for this is to enable
splitting the {,p}lxvp or {,p}stxvp instructions after reload without needing a
scratch GPR register.

The default for -mcpu=power10 is that both load vector pair and store vector
pair are enabled.

I added code so that the user code can modify these settings using either a
'#pragma GCC target' directive or used __attribute__((__target__(...))) in the
function declaration.

I added tests for the switches, #pragma, and attribute options.

I have built this on both little endian power10 systems and big endian power9
systems doing the normal bootstrap and test.  There were no regressions in any
of the tests, and the new tests passed.  Can I check this patch into the master
branch?

2023-11-09  Michael Meissner  <meissner@linux.ibm.com>

gcc/

	* config/rs6000/mma.md (movoo): Add support for -mno-load-vector-pair and
	-mno-store-vector-pair.
	* config/rs6000/rs6000-cpus.def (OTHER_POWER10_MASKS): Add support for
	-mload-vector-pair and -mstore-vector-pair.
	(POWERPC_MASKS): Likewise.
	* config/rs6000/rs6000.cc (rs6000_setup_reg_addr_masks): Only allow
	indexed mode for OOmode if we are generating both load vector pair and
	store vector pair instructions.
	(rs6000_option_override_internal): Add support for -mno-load-vector-pair
	and -mno-store-vector-pair.
	(rs6000_opt_masks): Likewise.
	* config/rs6000/rs6000.md (isa attribute): Add lxvp and stxvp
	attributes.
	(enabled attribute): Likewise.
	* config/rs6000/rs6000.opt (-mload-vector-pair): New option.
	(-mstore-vector-pair): Likewise.

gcc/testsuite/

	* gcc.target/powerpc/vector-pair-attribute.c: New test.
	* gcc.target/powerpc/vector-pair-pragma.c: New test.
	* gcc.target/powerpc/vector-pair-switch1.c: New test.
	* gcc.target/powerpc/vector-pair-switch2.c: New test.
	* gcc.target/powerpc/vector-pair-switch3.c: New test.
	* gcc.target/powerpc/vector-pair-switch4.c: New test.
---
 gcc/config/rs6000/mma.md                      | 19 +++++--
 gcc/config/rs6000/rs6000-cpus.def             |  8 ++-
 gcc/config/rs6000/rs6000.cc                   | 30 +++++++++-
 gcc/config/rs6000/rs6000.md                   | 10 +++-
 gcc/config/rs6000/rs6000.opt                  |  8 +++
 .../powerpc/vector-pair-attribute.c           | 39 +++++++++++++
 .../gcc.target/powerpc/vector-pair-pragma.c   | 55 +++++++++++++++++++
 .../gcc.target/powerpc/vector-pair-switch1.c  | 16 ++++++
 .../gcc.target/powerpc/vector-pair-switch2.c  | 17 ++++++
 .../gcc.target/powerpc/vector-pair-switch3.c  | 17 ++++++
 .../gcc.target/powerpc/vector-pair-switch4.c  | 17 ++++++
 11 files changed, 225 insertions(+), 11 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-pair-attribute.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-pair-pragma.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-pair-switch1.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-pair-switch2.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-pair-switch3.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-pair-switch4.c
diff mbox series

Patch

diff --git a/gcc/config/rs6000/mma.md b/gcc/config/rs6000/mma.md
index 575751d477e..3efb94be84f 100644
--- a/gcc/config/rs6000/mma.md
+++ b/gcc/config/rs6000/mma.md
@@ -292,27 +292,34 @@  (define_expand "movoo"
     gcc_assert (false);
 })
 
+;; If the user used -mno-store-vector-pair or -mno-load-vector pair, use an
+;; alternative that does not allow indexed addresses so we can split the load
+;; or store.
 (define_insn_and_split "*movoo"
-  [(set (match_operand:OO 0 "nonimmediate_operand" "=wa,ZwO,wa")
-	(match_operand:OO 1 "input_operand" "ZwO,wa,wa"))]
+  [(set (match_operand:OO 0 "nonimmediate_operand" "=wa,wa,ZwO,QwO,wa")
+	(match_operand:OO 1 "input_operand" "ZwO,QwO,wa,wa,wa"))]
   "TARGET_MMA
    && (gpc_reg_operand (operands[0], OOmode)
        || gpc_reg_operand (operands[1], OOmode))"
   "@
    lxvp%X1 %x0,%1
+   #
    stxvp%X0 %x1,%0
+   #
    #"
   "&& reload_completed
-   && (!MEM_P (operands[0]) && !MEM_P (operands[1]))"
+   && ((MEM_P (operands[0]) && !TARGET_STORE_VECTOR_PAIR)
+       || (MEM_P (operands[1]) && !TARGET_LOAD_VECTOR_PAIR)
+       || (!MEM_P (operands[0]) && !MEM_P (operands[1])))"
   [(const_int 0)]
 {
   rs6000_split_multireg_move (operands[0], operands[1]);
   DONE;
 }
-  [(set_attr "type" "vecload,vecstore,veclogical")
+  [(set_attr "type" "vecload,vecload,vecstore,vecstore,veclogical")
    (set_attr "size" "256")
-   (set_attr "length" "*,*,8")])
-
+   (set_attr "length" "*,8,*,8,8")
+   (set_attr "isa" "lxvp,*,stxvp,*,*")])
 
 ;; Vector quad support.  XOmode can only live in FPRs.
 (define_expand "movxo"
diff --git a/gcc/config/rs6000/rs6000-cpus.def b/gcc/config/rs6000/rs6000-cpus.def
index 4f350da378c..75435a52d1a 100644
--- a/gcc/config/rs6000/rs6000-cpus.def
+++ b/gcc/config/rs6000/rs6000-cpus.def
@@ -77,10 +77,12 @@ 
 /* Flags that need to be turned off if -mno-power10.  */
 /* We comment out PCREL_OPT here to disable it by default because SPEC2017
    performance was degraded by it.  */
-#define OTHER_POWER10_MASKS	(OPTION_MASK_MMA			\
+#define OTHER_POWER10_MASKS	(OPTION_MASK_LOAD_VECTOR_PAIR		\
+				 | OPTION_MASK_MMA			\
 				 | OPTION_MASK_PCREL			\
 				 /* | OPTION_MASK_PCREL_OPT */		\
-				 | OPTION_MASK_PREFIXED)
+				 | OPTION_MASK_PREFIXED			\
+				 | OPTION_MASK_STORE_VECTOR_PAIR)
 
 #define ISA_3_1_MASKS_SERVER	(ISA_3_0_MASKS_SERVER			\
 				 | OPTION_MASK_POWER10			\
@@ -130,6 +132,7 @@ 
 				 | OPTION_MASK_FLOAT128_HW		\
 				 | OPTION_MASK_FLOAT128_KEYWORD		\
 				 | OPTION_MASK_FPRND			\
+				 | OPTION_MASK_LOAD_VECTOR_PAIR		\
 				 | OPTION_MASK_POWER10			\
 				 | OPTION_MASK_P10_FUSION		\
 				 | OPTION_MASK_HTM			\
@@ -156,6 +159,7 @@ 
 				 | OPTION_MASK_QUAD_MEMORY_ATOMIC	\
 				 | OPTION_MASK_RECIP_PRECISION		\
 				 | OPTION_MASK_SOFT_FLOAT		\
+				 | OPTION_MASK_STORE_VECTOR_PAIR	\
 				 | OPTION_MASK_STRICT_ALIGN_OPTIONAL	\
 				 | OPTION_MASK_VSX)
 
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 5f56c3ed85b..db60d3ca960 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -2711,7 +2711,9 @@  rs6000_setup_reg_addr_masks (void)
 	  /* Vector pairs can do both indexed and offset loads if the
 	     instructions are enabled, otherwise they can only do offset loads
 	     since it will be broken into two vector moves.  Vector quads can
-	     only do offset loads.  */
+	     only do offset loads.  If the user restricted generation of either
+	     of the LXVP or STXVP instructions, do not allow indexed mode so
+	     that we can split the load/store.  */
 	  else if ((addr_mask != 0) && TARGET_MMA
 		   && (m2 == OOmode || m2 == XOmode))
 	    {
@@ -2719,7 +2721,9 @@  rs6000_setup_reg_addr_masks (void)
 	      if (rc == RELOAD_REG_FPR || rc == RELOAD_REG_VMX)
 		{
 		  addr_mask |= RELOAD_REG_QUAD_OFFSET;
-		  if (m2 == OOmode)
+		  if (m2 == OOmode
+		      && TARGET_LOAD_VECTOR_PAIR
+		      && TARGET_STORE_VECTOR_PAIR)
 		    addr_mask |= RELOAD_REG_INDEXED;
 		}
 	    }
@@ -4405,6 +4409,26 @@  rs6000_option_override_internal (bool global_init_p)
       rs6000_isa_flags &= ~OPTION_MASK_MMA;
     }
 
+  /* Warn if -m-load-vector-pair or -m-store-vector-pair are used and MMA is
+     not set.  */
+  if (!TARGET_MMA && TARGET_LOAD_VECTOR_PAIR)
+    {
+      if ((rs6000_isa_flags_explicit & OPTION_MASK_LOAD_VECTOR_PAIR) != 0)
+	warning (0, "%qs should not be used unless you use %qs",
+		 "-mload-vector-pair", "-mmma");
+
+      rs6000_isa_flags &= ~OPTION_MASK_LOAD_VECTOR_PAIR;
+    }
+
+  if (!TARGET_MMA && TARGET_STORE_VECTOR_PAIR)
+    {
+      if ((rs6000_isa_flags_explicit & OPTION_MASK_STORE_VECTOR_PAIR) != 0)
+	warning (0, "%qs should not be used unless you use %qs",
+		 "-mstore-vector-pair", "-mmma");
+
+      rs6000_isa_flags &= OPTION_MASK_STORE_VECTOR_PAIR;
+    }
+
   /* Enable power10 fusion if we are tuning for power10, even if we aren't
      generating power10 instructions.  */
   if (!(rs6000_isa_flags_explicit & OPTION_MASK_P10_FUSION))
@@ -24437,6 +24461,7 @@  static struct rs6000_opt_mask const rs6000_opt_masks[] =
   { "hard-dfp",			OPTION_MASK_DFP,		false, true  },
   { "htm",			OPTION_MASK_HTM,		false, true  },
   { "isel",			OPTION_MASK_ISEL,		false, true  },
+  { "load-vector-pair",		OPTION_MASK_LOAD_VECTOR_PAIR,	false, true  },
   { "mfcrf",			OPTION_MASK_MFCRF,		false, true  },
   { "mfpgpr",			0,				false, true  },
   { "mma",			OPTION_MASK_MMA,		false, true  },
@@ -24461,6 +24486,7 @@  static struct rs6000_opt_mask const rs6000_opt_masks[] =
   { "quad-memory-atomic",	OPTION_MASK_QUAD_MEMORY_ATOMIC,	false, true  },
   { "recip-precision",		OPTION_MASK_RECIP_PRECISION,	false, true  },
   { "save-toc-indirect",	OPTION_MASK_SAVE_TOC_INDIRECT,	false, true  },
+  { "store-vector-pair",	OPTION_MASK_STORE_VECTOR_PAIR,	false, true  },
   { "string",			0,				false, true  },
   { "update",			OPTION_MASK_NO_UPDATE,		true , true  },
   { "vsx",			OPTION_MASK_VSX,		false, true  },
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 2a1b5ecfaee..dcf1f3526f5 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -355,7 +355,7 @@  (define_attr "cpu"
   (const (symbol_ref "(enum attr_cpu) rs6000_tune")))
 
 ;; The ISA we implement.
-(define_attr "isa" "any,p5,p6,p7,p7v,p8v,p9,p9v,p9kf,p9tf,p10"
+(define_attr "isa" "any,p5,p6,p7,p7v,p8v,p9,p9v,p9kf,p9tf,p10,lxvp,stxvp"
   (const_string "any"))
 
 ;; Is this alternative enabled for the current CPU/ISA/etc.?
@@ -403,6 +403,14 @@  (define_attr "enabled" ""
      (and (eq_attr "isa" "p10")
 	  (match_test "TARGET_POWER10"))
      (const_int 1)
+
+     (and (eq_attr "isa" "lxvp")
+	  (match_test "TARGET_LOAD_VECTOR_PAIR"))
+     (const_int 1)
+
+     (and (eq_attr "isa" "stxvp")
+	  (match_test "TARGET_STORE_VECTOR_PAIR"))
+     (const_int 1)
     ] (const_int 0)))
 
 ;; If this instruction is microcoded on the CELL processor
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index bde6d3ff664..369095df9ed 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -597,6 +597,14 @@  mmma
 Target Mask(MMA) Var(rs6000_isa_flags)
 Generate (do not generate) MMA instructions.
 
+mload-vector-pair
+Target Undocumented Mask(LOAD_VECTOR_PAIR) Var(rs6000_isa_flags)
+Generate (do not generate) load vector pair instructions.
+
+mstore-vector-pair
+Target Undocumented Mask(STORE_VECTOR_PAIR) Var(rs6000_isa_flags)
+Generate (do not generate) store vector pair instructions.
+
 mrelative-jumptables
 Target Undocumented Var(rs6000_relative_jumptables) Init(1) Save
 
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-pair-attribute.c b/gcc/testsuite/gcc.target/powerpc/vector-pair-attribute.c
new file mode 100644
index 00000000000..985a44aca85
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-pair-attribute.c
@@ -0,0 +1,39 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+/* Test if we can control generating load and store vector pair via the target
+   attribute.  */
+
+__attribute__((__target__("load-vector-pair,store-vector-pair")))
+void
+test_load_store (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 1 lxvp, 1 stxvp.  */
+}
+
+__attribute__((__target__("load-vector-pair,no-store-vector-pair")))
+void
+test_load_no_store (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 1 lxvp, 2 stxv.  */
+}
+
+__attribute__((__target__("no-load-vector-pair,store-vector-pair")))
+void
+test_store_no_load (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 2 lxv, 1 stxvp.  */
+}
+
+__attribute__((__target__("no-load-vector-pair,no-store-vector-pair")))
+void
+test_no_load_or_store (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 2 lxv, 2 stxv.  */
+}
+
+/* { dg-final { scan-assembler-times {\mp?lxvpx?\M}  2 } } */
+/* { dg-final { scan-assembler-times {\mp?stxvpx?\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mp?lxvx?\M}   4 } } */
+/* { dg-final { scan-assembler-times {\mp?stxvx?\M}  4 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-pair-pragma.c b/gcc/testsuite/gcc.target/powerpc/vector-pair-pragma.c
new file mode 100644
index 00000000000..74c6baf8185
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-pair-pragma.c
@@ -0,0 +1,55 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+/* Test if we can control generating load and store vector pair via the #pragma
+   directive.  */
+
+#pragma gcc push_options
+#pragma GCC target("load-vector-pair,store-vector-pair")
+
+void
+test_load_store (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 1 lxvp, 1 stxvp.  */
+}
+
+#pragma gcc pop_options
+
+#pragma gcc push_options
+#pragma GCC target("load-vector-pair,no-store-vector-pair")
+
+void
+test_load_no_store (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 1 lxvp, 2 stxv.  */
+}
+
+#pragma gcc pop_options
+
+#pragma gcc push_options
+#pragma GCC target("no-load-vector-pair,store-vector-pair")
+
+void
+test_store_no_load (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 2 lxv, 1 stxvp.  */
+}
+
+#pragma gcc pop_options
+
+#pragma gcc push_options
+#pragma GCC target("no-load-vector-pair,no-store-vector-pair")
+
+void
+test_no_load_or_store (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 2 lxv, 2 stxv.  */
+}
+
+#pragma gcc pop_options
+
+/* { dg-final { scan-assembler-times {\mp?lxvpx?\M}  2 } } */
+/* { dg-final { scan-assembler-times {\mp?stxvpx?\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mp?lxvx?\M}   4 } } */
+/* { dg-final { scan-assembler-times {\mp?stxvx?\M}  4 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-pair-switch1.c b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch1.c
new file mode 100644
index 00000000000..48e433b378e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch1.c
@@ -0,0 +1,16 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+/* Test if we generate load and store vector pair by default on power 10.  */
+
+void
+test (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 1 lxvp, 1 stxvp.  */
+}
+
+/* { dg-final { scan-assembler-times {\mp?lxvpx?\M}  1 } } */
+/* { dg-final { scan-assembler-times {\mp?stxvpx?\M} 1 } } */
+/* { dg-final { scan-assembler-not   {\mp?lxvx?\M}     } } */
+/* { dg-final { scan-assembler-not   {\mp?stxvx?\M}    } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-pair-switch2.c b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch2.c
new file mode 100644
index 00000000000..2a38c2f2aae
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch2.c
@@ -0,0 +1,17 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2 -mno-store-vector-pair" } */
+
+/* Test if we generate load vector pair but not store vector pair if
+   -mno-store-vector-pair is used on power10.  */
+
+void
+test (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 1 lxvp, 2 stxv.  */
+}
+
+/* { dg-final { scan-assembler-times {\mp?lxvpx?\M}  1 } } */
+/* { dg-final { scan-assembler-not   {\mp?stxvpx?\M}   } } */
+/* { dg-final { scan-assembler-not   {\mp?lxvx?\M}     } } */
+/* { dg-final { scan-assembler-times {\mp?stxvx?\M}  2 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-pair-switch3.c b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch3.c
new file mode 100644
index 00000000000..fd273056b8f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch3.c
@@ -0,0 +1,17 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2 -mno-load-vector-pair" } */
+
+/* Test if we do not generate load vector pair but generate store vector pair
+   if -mno-load-vector-pair is used on power10.  */
+
+void
+test (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 2 lxv, 1 stxvp.  */
+}
+
+/* { dg-final { scan-assembler-not   {\mp?lxvpx?\M}    } } */
+/* { dg-final { scan-assembler-times {\mp?stxvpx?\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mp?lxvx?\M}   2 } } */
+/* { dg-final { scan-assembler-not   {\mp?stxvx?\M}    } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-pair-switch4.c b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch4.c
new file mode 100644
index 00000000000..01686e073fe
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-pair-switch4.c
@@ -0,0 +1,17 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2 -mno-load-vector-pair -mno-store-vector-pair" } */
+
+/* Test if we do not generate load and store vector pair if directed to on
+   power 10.  */
+
+void
+test (__vector_pair *p, __vector_pair *q)
+{
+  *p = *q;	/* 2 lxv, 2 stxv.  */
+}
+
+/* { dg-final { scan-assembler-not   {\mp?lxvpx?\M}    } } */
+/* { dg-final { scan-assembler-not   {\mp?stxvpx?\M}   } } */
+/* { dg-final { scan-assembler-times {\mp?lxvx?\M}   2 } } */
+/* { dg-final { scan-assembler-times {\mp?stxvx?\M}  2 } } */