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PR9218: SimplifyDemandedVectorElts can return a non-null value that is not 

the instruction passed in.  Make sure to account for this correctly, instead
of looping infinitely.

llvm-svn: 126058
This commit is contained in:
Eli Friedman 2011-02-19 22:42:40 +00:00
parent 5b05454f24
commit ef200db4fd
2 changed files with 18 additions and 2 deletions
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9
llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
View File

@ -426,8 +426,11 @@ Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements();
APInt UndefElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
if (SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts))
if (Value *V = SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts)) {
if (V != &IE)
return ReplaceInstUsesWith(IE, V);
return &IE;
}
return 0;
}
@ -451,7 +454,9 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
APInt UndefElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
if (SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
if (Value *V = SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
if (V != &SVI)
return ReplaceInstUsesWith(SVI, V);
LHS = SVI.getOperand(0);
RHS = SVI.getOperand(1);
MadeChange = true;

11
llvm/test/Transforms/InstCombine/2011-02-16-InsertelementHang.ll Normal file
View File

@ -0,0 +1,11 @@
; RUN: opt < %s -instcombine -S | FileCheck %s
; PR9218
%vec2x2 = type { <2 x double>, <2 x double> }
define %vec2x2 @split(double) nounwind alwaysinline {
; CHECK: @split
; CHECK: ret %vec2x2 undef
%vba = insertelement <2 x double> undef, double %0, i32 2
ret <2 x double> %vba, <2 x double> %vba
}