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Fix a bug in r123034 (trying to sext/zext non-integers) and clean up a little. 

llvm-svn: 123061
This commit is contained in:
Frits van Bommel 2011-01-08 10:51:36 +00:00
parent 8c5defd0b0
commit 6a1fb8f235
2 changed files with 14 additions and 5 deletions
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13
llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
View File

@ -299,6 +299,11 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
case ICmpInst::ICMP_SLT:
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_SGT: {
// These transformations only work for selects over integers.
const IntegerType *SelectTy = dyn_cast<IntegerType>(SI.getType());
if (!SelectTy)
break;
Constant *AdjustedRHS;
if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT)
AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() + 1);
@ -315,9 +320,8 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
// promote all to the larger type. This enables scalar evolution to
// analyze this expression.
else if (CmpRHS->getType()->getScalarSizeInBits()
< SI.getType()->getScalarSizeInBits()) {
Constant *sextRHS = ConstantExpr::getSExt(AdjustedRHS,
SI.getType());
< SelectTy->getBitWidth()) {
Constant *sextRHS = ConstantExpr::getSExt(AdjustedRHS, SelectTy);
// X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
// X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
@ -332,8 +336,7 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
CmpLHS = FalseVal;
AdjustedRHS = sextRHS;
} else if (ICI->isUnsigned()) {
Constant *zextRHS = ConstantExpr::getZExt(AdjustedRHS,
SI.getType());
Constant *zextRHS = ConstantExpr::getZExt(AdjustedRHS, SelectTy);
// X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
// X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
// zext + signed compare cannot be changed:

6
llvm/test/Transforms/InstCombine/crash.ll
View File

@ -335,3 +335,9 @@ ret void
declare i32 @func_14()
define double @test16(i32 %a) nounwind {
%cmp = icmp slt i32 %a, 2
%select = select i1 %cmp, double 2.000000e+00, double 3.141592e+00
ret double %select
}