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Fix PR1932 by disabling an xform invalid for fdiv.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46429 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-01-28 00:58:18 +00:00
parent 5ec898399f
commit 25feae555d
2 changed files with 17 additions and 9 deletions
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19
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -2494,14 +2494,15 @@ Instruction *InstCombiner::commonDivTransforms(BinaryOperator &I) {
if (isa<UndefValue>(Op1))
return ReplaceInstUsesWith(I, Op1);
// Handle cases involving: div X, (select Cond, Y, Z)
// Handle cases involving: [su]div X, (select Cond, Y, Z)
// This does not apply for fdiv.
if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) {
// div X, (Cond ? 0 : Y) -> div X, Y. If the div and the select are in the
// same basic block, then we replace the select with Y, and the condition
// of the select with false (if the cond value is in the same BB). If the
// select has uses other than the div, this allows them to be simplified
// also. Note that div X, Y is just as good as div X, 0 (undef)
if (Constant *ST = dyn_cast<Constant>(SI->getOperand(1)))
// [su]div X, (Cond ? 0 : Y) -> div X, Y. If the div and the select are in
// the same basic block, then we replace the select with Y, and the
// condition of the select with false (if the cond value is in the same BB).
// If the select has uses other than the div, this allows them to be
// simplified also. Note that div X, Y is just as good as div X, 0 (undef)
if (ConstantInt *ST = dyn_cast<ConstantInt>(SI->getOperand(1)))
if (ST->isNullValue()) {
Instruction *CondI = dyn_cast<Instruction>(SI->getOperand(0));
if (CondI && CondI->getParent() == I.getParent())
@ -2513,8 +2514,8 @@ Instruction *InstCombiner::commonDivTransforms(BinaryOperator &I) {
return &I;
}
// Likewise for: div X, (Cond ? Y : 0) -> div X, Y
if (Constant *ST = dyn_cast<Constant>(SI->getOperand(2)))
// Likewise for: [su]div X, (Cond ? Y : 0) -> div X, Y
if (ConstantInt *ST = dyn_cast<ConstantInt>(SI->getOperand(2)))
if (ST->isNullValue()) {
Instruction *CondI = dyn_cast<Instruction>(SI->getOperand(0));
if (CondI && CondI->getParent() == I.getParent())

7
test/Transforms/InstCombine/2008-01-27-FloatSelect.ll Normal file
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@ -0,0 +1,7 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep select
define double @fold(i1 %a, double %b) {
%s = select i1 %a, double 0., double 1.
%c = fdiv double %b, %s
ret double %c
}