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| author | Michael Liao <michael.liao@intel.com> | 2012-08-31 20:12:31 +0000 |
|---|---|---|
| committer | Michael Liao <michael.liao@intel.com> | 2012-08-31 20:12:31 +0000 |
| commit | 3224543bf90a7fe52a15052b2e2339cea7d669c1 (patch) | |
| tree | aff31fd8322100327c1998bbba8696a76e1891a0 /llvm/lib | |
| parent | 0e337543dcadb5baceec59c4f87f48cf204449bb (diff) | |
| download | bcm5719-llvm-3224543bf90a7fe52a15052b2e2339cea7d669c1.tar.gz bcm5719-llvm-3224543bf90a7fe52a15052b2e2339cea7d669c1.zip | |
Fix PR12359
- In addition to undefined, if V2 is zero vector, skip 2nd PSHUFB and POR as
well as PSHUFB will zero elements with negative indices.
Patch by Sriram Murali <sriram.murali@intel.com>
llvm-svn: 163018
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index f9184f693db..f4329d3bf9d 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -5881,8 +5881,6 @@ SDValue LowerVECTOR_SHUFFLEv16i8(ShuffleVectorSDNode *SVOp, DebugLoc dl = SVOp->getDebugLoc(); ArrayRef<int> MaskVals = SVOp->getMask(); - bool V2IsUndef = V2.getOpcode() == ISD::UNDEF; - // If we have SSSE3, case 1 is generated when all result bytes come from // one of the inputs. Otherwise, case 2 is generated. If no SSSE3 is // present, fall back to case 3. @@ -5906,7 +5904,11 @@ SDValue LowerVECTOR_SHUFFLEv16i8(ShuffleVectorSDNode *SVOp, V1 = DAG.getNode(X86ISD::PSHUFB, dl, MVT::v16i8, V1, DAG.getNode(ISD::BUILD_VECTOR, dl, MVT::v16i8, &pshufbMask[0], 16)); - if (V2IsUndef) + + // As PSHUFB will zero elements with negative indices, it's safe to ignore + // the 2nd operand if it's undefined or zero. + if (V2.getOpcode() == ISD::UNDEF || + ISD::isBuildVectorAllZeros(V2.getNode())) return V1; // Calculate the shuffle mask for the second input, shuffle it, and |
