Fix a bug with <8 x i16> shuffle lowering on X86 where parts of the

shuffle could be skipped.  The check is invalid because the loop index i 
doesn't correspond to the element actually inserted. The correct check is
already done a few lines earlier, for whether the element is already in 
the right spot, so this shouldn't have any effect on the codegen for 
code that was already correct.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52486 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman 2008-06-19 06:09:51 +00:00
parent 29b039976f
commit 2c8e64d3e4
2 changed files with 10 additions and 2 deletions

View File

@ -3445,8 +3445,6 @@ SDOperand LowerVECTOR_SHUFFLEv8i16(SDOperand V1, SDOperand V2,
continue;
SDOperand Elt = MaskElts[i];
unsigned EltIdx = cast<ConstantSDNode>(Elt)->getValue();
if (EltIdx == i)
continue;
SDOperand ExtOp = (EltIdx < 8)
? DAG.getNode(ISD::EXTRACT_VECTOR_ELT, MVT::i16, V1,
DAG.getConstant(EltIdx, PtrVT))

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@ -0,0 +1,10 @@
; RUN: llvm-as < %s | llc -march=x86 -mcpu=i386 -mattr=+sse2 | grep pinsrw
; Test to make sure we actually insert the bottom element of the vector
define <8 x i16> @a(<8 x i16> %a) nounwind {
entry:
shufflevector <8 x i16> %a, <8 x i16> zeroinitializer, <8 x i32> < i32 0, i32 8, i32 8, i32 8, i32 8, i32 8, i32 8, i32 8 >
%add = add <8 x i16> %0, %a
ret <8 x i16> %add
}