[PATCH, i386]: Fix PR50788, [4.7 Regression] ICE: in merge_overlapping_regs, at regrename.c:318 with -mavx -fpeel-loops -fstack-protector-all and __builtin_ia32_maskloadpd256

[Uros Bizjak <ubizjak at gmail dot com>]

Hello!

As discussed in the PR, avx{,2}_maskload pattern outputs zero element
to destination register, when corresponding mask selector is not set.
So, there is no dependency on target register value.

While the attached patch fixes mainline, following one-liner is enough
to fix other relase branches.

Index: config/i386/sse.md
===================================================================
--- config/i386/sse.md	(revision 180334)
+++ config/i386/sse.md	(working copy)
@@ -12007,8 +12007,7 @@
   [(set (match_operand:AVXMODEF2P 0 "register_operand" "=x")
 	(unspec:AVXMODEF2P
 	  [(match_operand:AVXMODEF2P 1 "memory_operand" "m")
-	   (match_operand:<avxpermvecmode> 2 "register_operand" "x")
-	   (match_dup 0)]
+	   (match_operand:<avxpermvecmode> 2 "register_operand" "x")]
 	  UNSPEC_MASKLOAD))]
   "TARGET_AVX"
   "vmaskmov<ssemodesuffix>\t{%1, %2, %0|%0, %2, %1}"


2011-10-23  Uros Bizjak  <ubizjak@gmail.com>

	PR target/50788
	* config/i386/sse.md (avx2_maskload<ssemodesuffix><avxsizesuffix>):
	Remove (match_dup 0).
	(*avx2_maskload<ssemodesuffix><avxsizesuffix>): New insn pattern.
	(*avx_maskload<ssemodesuffix><avxsizesuffix>): Ditto.
	(*avx2_maskstore<ssemodesuffix><avxsizesuffix>): Ditto.
	(*avx_maskstore<ssemodesuffix><avxsizesuffix>): Ditto.
	(*avx2_maskmov<ssemodesuffix><avxsizesuffix>): Remove insn pattern.
	(*avx_maskmov<ssemodesuffix><avxsizesuffix>): Ditto.

testsuite/ChangeLog:

2011-10-23  Uros Bizjak  <ubizjak@gmail.com>

	PR target/50788
	* testsuite/gcc.target/i386/pr50788.c: New test.

Patch was bootstrapped and regression tested on x86_64-pc-linux-gnu
{,-m32}. I will commit this patch to mainline and 4.6 branch as soon
as regression tests finish.

Uros.

Attachment: p.diff.txt
Description: Text document