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[indvars] Fix bugs in floating point IV range checks noticed by inspection.

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llvm-svn: 139574
This commit is contained in:
Andrew Trick
2011-09-13 01:59:32 +00:00
parent 40ddfedd6c
commit 3de5b8e4c1
2 changed files with 13 additions and 13 deletions
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20
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
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@@ -351,14 +351,14 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PN) {
// Positive and negative strides have different safety conditions.
if (IncValue > 0) {
// If we have a positive stride, we require the init to be less than the
// exit value and an equality or less than comparison.
if (InitValue >= ExitValue ||
NewPred == CmpInst::ICMP_SGT || NewPred == CmpInst::ICMP_SGE)
// exit value.
if (InitValue >= ExitValue)
return;
uint32_t Range = uint32_t(ExitValue-InitValue);
if (NewPred == CmpInst::ICMP_SLE) {
// Normalize SLE -> SLT, check for infinite loop.
// Check for infinite loop, either:
// while (i <= Exit) or until (i > Exit)
if (NewPred == CmpInst::ICMP_SLE || NewPred == CmpInst::ICMP_SGT) {
if (++Range == 0) return; // Range overflows.
}
@@ -378,14 +378,14 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PN) {
} else {
// If we have a negative stride, we require the init to be greater than the
// exit value and an equality or greater than comparison.
if (InitValue >= ExitValue ||
NewPred == CmpInst::ICMP_SLT || NewPred == CmpInst::ICMP_SLE)
// exit value.
if (InitValue <= ExitValue)
return;
uint32_t Range = uint32_t(InitValue-ExitValue);
if (NewPred == CmpInst::ICMP_SGE) {
// Normalize SGE -> SGT, check for infinite loop.
// Check for infinite loop, either:
// while (i >= Exit) or until (i < Exit)
if (NewPred == CmpInst::ICMP_SGE || NewPred == CmpInst::ICMP_SLT) {
if (++Range == 0) return; // Range overflows.
}