[llvm] r304894 - [X86][SSE] Fix an issue with PEXTRW/PEXTRB indices during shuffle combining

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Wed Jun  7 05:30:35 2017
New Revision: 304894

URL: http://llvm.org/viewvc/llvm-project?rev=304894&view=rev
Log:
[X86][SSE] Fix an issue with PEXTRW/PEXTRB indices during shuffle combining

We were checking that the index was in range of the destination vector type, not the (larger) source vector type

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/clear_upper_vector_element_bits.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=304894&r1=304893&r2=304894&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Wed Jun  7 05:30:35 2017
@@ -5868,8 +5868,7 @@ static bool getFauxShuffleMask(SDValue N
       assert(SrcExtract.getOperand(0).getValueType() == MVT::v16i8);
     }
 
-    if (!SrcExtract || !isa<ConstantSDNode>(SrcExtract.getOperand(1)) ||
-        NumElts <= SrcExtract.getConstantOperandVal(1))
+    if (!SrcExtract || !isa<ConstantSDNode>(SrcExtract.getOperand(1)))
       return false;
 
     SDValue SrcVec = SrcExtract.getOperand(0);
@@ -5877,8 +5876,12 @@ static bool getFauxShuffleMask(SDValue N
     unsigned NumSrcElts = SrcVT.getVectorNumElements();
     unsigned NumZeros = (NumBitsPerElt / SrcVT.getScalarSizeInBits()) - 1;
 
+    unsigned SrcIdx = SrcExtract.getConstantOperandVal(1);
+    if (NumSrcElts <= SrcIdx)
+      return false;
+
     Ops.push_back(SrcVec);
-    Mask.push_back(SrcExtract.getConstantOperandVal(1));
+    Mask.push_back(SrcIdx);
     Mask.append(NumZeros, SM_SentinelZero);
     Mask.append(NumSrcElts - Mask.size(), SM_SentinelUndef);
     return true;

Modified: llvm/trunk/test/CodeGen/X86/clear_upper_vector_element_bits.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/clear_upper_vector_element_bits.ll?rev=304894&r1=304893&r2=304894&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/clear_upper_vector_element_bits.ll (original)
+++ llvm/trunk/test/CodeGen/X86/clear_upper_vector_element_bits.ll Wed Jun  7 05:30:35 2017
@@ -159,19 +159,7 @@ define <8 x i32> @_clearupper8xi32a(<8 x
 define <8 x i16> @_clearupper8xi16a(<8 x i16>) nounwind {
 ; SSE-LABEL: _clearupper8xi16a:
 ; SSE:       # BB#0:
-; SSE-NEXT:    pextrw $4, %xmm0, %eax
-; SSE-NEXT:    pextrw $5, %xmm0, %ecx
-; SSE-NEXT:    pextrw $6, %xmm0, %edx
-; SSE-NEXT:    pextrw $7, %xmm0, %esi
-; SSE-NEXT:    movd %esi, %xmm1
-; SSE-NEXT:    movd %edx, %xmm2
-; SSE-NEXT:    punpcklwd {{.*#+}} xmm2 = xmm2[0],xmm1[0],xmm2[1],xmm1[1],xmm2[2],xmm1[2],xmm2[3],xmm1[3]
-; SSE-NEXT:    movd %ecx, %xmm1
-; SSE-NEXT:    movd %eax, %xmm3
-; SSE-NEXT:    punpcklwd {{.*#+}} xmm3 = xmm3[0],xmm1[0],xmm3[1],xmm1[1],xmm3[2],xmm1[2],xmm3[3],xmm1[3]
-; SSE-NEXT:    punpckldq {{.*#+}} xmm3 = xmm3[0],xmm2[0],xmm3[1],xmm2[1]
-; SSE-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm3[0]
-; SSE-NEXT:    pand {{.*}}(%rip), %xmm0
+; SSE-NEXT:    andps {{.*}}(%rip), %xmm0
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: _clearupper8xi16a:
@@ -216,33 +204,9 @@ define <8 x i16> @_clearupper8xi16a(<8 x
 define <16 x i16> @_clearupper16xi16a(<16 x i16>) nounwind {
 ; SSE-LABEL: _clearupper16xi16a:
 ; SSE:       # BB#0:
-; SSE-NEXT:    pextrw $4, %xmm0, %eax
-; SSE-NEXT:    pextrw $5, %xmm0, %ecx
-; SSE-NEXT:    pextrw $6, %xmm0, %edx
-; SSE-NEXT:    pextrw $7, %xmm0, %esi
-; SSE-NEXT:    pextrw $4, %xmm1, %r8d
-; SSE-NEXT:    pextrw $5, %xmm1, %r9d
-; SSE-NEXT:    pextrw $6, %xmm1, %r10d
-; SSE-NEXT:    pextrw $7, %xmm1, %edi
-; SSE-NEXT:    movd %esi, %xmm2
-; SSE-NEXT:    movd %edx, %xmm3
-; SSE-NEXT:    punpcklwd {{.*#+}} xmm3 = xmm3[0],xmm2[0],xmm3[1],xmm2[1],xmm3[2],xmm2[2],xmm3[3],xmm2[3]
-; SSE-NEXT:    movd %ecx, %xmm2
-; SSE-NEXT:    movd %eax, %xmm4
-; SSE-NEXT:    punpcklwd {{.*#+}} xmm4 = xmm4[0],xmm2[0],xmm4[1],xmm2[1],xmm4[2],xmm2[2],xmm4[3],xmm2[3]
-; SSE-NEXT:    punpckldq {{.*#+}} xmm4 = xmm4[0],xmm3[0],xmm4[1],xmm3[1]
-; SSE-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm4[0]
-; SSE-NEXT:    movdqa {{.*#+}} xmm2 = [255,255,255,255,255,255,255,255]
-; SSE-NEXT:    pand %xmm2, %xmm0
-; SSE-NEXT:    movd %edi, %xmm3
-; SSE-NEXT:    movd %r10d, %xmm4
-; SSE-NEXT:    punpcklwd {{.*#+}} xmm4 = xmm4[0],xmm3[0],xmm4[1],xmm3[1],xmm4[2],xmm3[2],xmm4[3],xmm3[3]
-; SSE-NEXT:    movd %r9d, %xmm3
-; SSE-NEXT:    movd %r8d, %xmm5
-; SSE-NEXT:    punpcklwd {{.*#+}} xmm5 = xmm5[0],xmm3[0],xmm5[1],xmm3[1],xmm5[2],xmm3[2],xmm5[3],xmm3[3]
-; SSE-NEXT:    punpckldq {{.*#+}} xmm5 = xmm5[0],xmm4[0],xmm5[1],xmm4[1]
-; SSE-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm5[0]
-; SSE-NEXT:    pand %xmm2, %xmm1
+; SSE-NEXT:    movaps {{.*#+}} xmm2 = [255,255,255,255,255,255,255,255]
+; SSE-NEXT:    andps %xmm2, %xmm0
+; SSE-NEXT:    andps %xmm2, %xmm1
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: _clearupper16xi16a: