[llvm] r295046 - [X86][SSE] Test case showing missed PSHUFB target shuffle constant fold opportunity.

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Tue Feb 14 05:20:11 2017
New Revision: 295046

URL: http://llvm.org/viewvc/llvm-project?rev=295046&view=rev
Log:
[X86][SSE] Test case showing missed PSHUFB target shuffle constant fold opportunity.

It also shows an unnecessary pshufb/broadcast being used - the original pshufb mask only requested the lowest byte.

Modified:
    llvm/trunk/test/CodeGen/X86/vector-shuffle-combining-ssse3.ll

Modified: llvm/trunk/test/CodeGen/X86/vector-shuffle-combining-ssse3.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-shuffle-combining-ssse3.ll?rev=295046&r1=295045&r2=295046&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vector-shuffle-combining-ssse3.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vector-shuffle-combining-ssse3.ll Tue Feb 14 05:20:11 2017
@@ -586,3 +586,38 @@ define <16 x i8> @constant_fold_pshufb()
   %1 = tail call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> <i8 15, i8 14, i8 13, i8 12, i8 11, i8 10, i8 9, i8 8, i8 7, i8 6, i8 5, i8 4, i8 3, i8 2, i8 1, i8 0>, <16 x i8> <i8 1, i8 -1, i8 -1, i8 -1, i8 undef, i8 undef, i8 -1, i8 -1, i8 15, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 7, i8 6>)
   ret <16 x i8> %1
 }
+
+; FIXME - unnecessary pshufb/broadcast being used - pshufb mask only needs lowest byte.
+define <16 x i8> @constant_fold_pshufb_2() {
+; SSE-LABEL: constant_fold_pshufb_2:
+; SSE:       # BB#0:
+; SSE-NEXT:    movl $2, %eax
+; SSE-NEXT:    movd %eax, %xmm0
+; SSE-NEXT:    pxor %xmm1, %xmm1
+; SSE-NEXT:    pshufb %xmm1, %xmm0
+; SSE-NEXT:    retq
+;
+; AVX1-LABEL: constant_fold_pshufb_2:
+; AVX1:       # BB#0:
+; AVX1-NEXT:    movl $2, %eax
+; AVX1-NEXT:    vmovd %eax, %xmm0
+; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
+; AVX1-NEXT:    vpshufb %xmm1, %xmm0, %xmm0
+; AVX1-NEXT:    retq
+;
+; AVX2-LABEL: constant_fold_pshufb_2:
+; AVX2:       # BB#0:
+; AVX2-NEXT:    movl $2, %eax
+; AVX2-NEXT:    vmovd %eax, %xmm0
+; AVX2-NEXT:    vpbroadcastb %xmm0, %xmm0
+; AVX2-NEXT:    retq
+;
+; AVX512F-LABEL: constant_fold_pshufb_2:
+; AVX512F:       # BB#0:
+; AVX512F-NEXT:    movl $2, %eax
+; AVX512F-NEXT:    vmovd %eax, %xmm0
+; AVX512F-NEXT:    vpbroadcastb %xmm0, %xmm0
+; AVX512F-NEXT:    retq
+  %1 = tail call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> <i8 2, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0>, <16 x i8> <i8 0, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef, i8 undef>)
+  ret <16 x i8> %1
+}