[PATCH]: all ones m128i constant

[Xinliang David Li <davidxl at google dot com>]

Hi, all one m128i constant can be materialized using pcmpeqd
instruction (compared with a memory load from rodata). This patch
implements this.

Bootstrapped/regression tested on linux-i686.

Ok to commit?

Thanks,

David

Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c	(revision 145332)
+++ config/i386/i386.c	(working copy)
@@ -8951,7 +8951,8 @@ legitimate_constant_p (rtx x)
       break;
 
     case CONST_VECTOR:
-      if (x == CONST0_RTX (GET_MODE (x)))
+      if (x == CONST0_RTX (GET_MODE (x))
+          || (vector_all_ones_operand (x, GET_MODE (x)) && TARGET_SSE))
 	return true;
       return false;
 
Index: testsuite/gcc.dg/all_one_m128i.c
===================================================================
--- testsuite/gcc.dg/all_one_m128i.c	(revision 0)
+++ testsuite/gcc.dg/all_one_m128i.c	(revision 0)
@@ -0,0 +1,41 @@
+/* { dg-do run { target x86_64-*-* i?86-*-* } } */
+/* { dg-options "-save-temps -O2 -msse2" } */
+
+
+#include <stdio.h>
+#include <xmmintrin.h>
+#include <emmintrin.h>
+__m128i m;
+__m128i m2;
+__attribute__((noinline))  __m128i foo()
+{
+  __m128i  minus_1 = __extension__(__m128i)(__v4si){-1,-1,-1,-1};
+  m = minus_1;
+  return minus_1;
+}
+
+
+int main ()
+{
+    unsigned *p, *p2;
+    p = (unsigned *)&m;
+    p2 =(unsigned *)&m2;
+    m2 = foo();
+
+    if (p[0] != (unsigned)-1 
+        || p[1] != (unsigned) -1
+        || p[2] != (unsigned) -1
+        || p[3] != (unsigned) -1)
+      return 1;
+
+    if (p2[0] != (unsigned)-1 
+        || p2[1] != (unsigned) -1
+        || p2[2] != (unsigned) -1
+        || p2[3] != (unsigned) -1)
+      return 2;
+        
+    return 0;
+}
+
+/* { dg-final { scan-assembler "pcmpeqd" } } */
+/* { dg-final { cleanup-saved-temps } } */

Attachment: cl5
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Attachment: cl5
Description: Binary data