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indvars: Added verification that LFTR and other indvars goodness does

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not interfere with BackedgeTakenCount computation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135412 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2011-07-18 18:44:20 +00:00
parent 5241b79ebc
commit f6a0dbaaf4
1 changed files with 20 additions and 1 deletions
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21
lib/Transforms/Scalar/IndVarSimplify.cpp
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@@ -1900,6 +1900,25 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
// Clean up dead instructions. // Clean up dead instructions.
Changed |= DeleteDeadPHIs(L->getHeader()); Changed |= DeleteDeadPHIs(L->getHeader());
// Check a post-condition. // Check a post-condition.
assert(L->isLCSSAForm(*DT) && "Indvars did not leave the loop in lcssa form!"); assert(L->isLCSSAForm(*DT) &&
"Indvars did not leave the loop in lcssa form!");
// Verify that LFTR, and any other change have not interfered with SCEV's
// ability to compute trip count.
#ifndef NDEBUG
if (DisableIVRewrite && !isa<SCEVCouldNotCompute>(BackedgeTakenCount)) {
SE->forgetLoop(L);
const SCEV *NewBECount = SE->getBackedgeTakenCount(L);
if (SE->getTypeSizeInBits(BackedgeTakenCount->getType()) <
SE->getTypeSizeInBits(NewBECount->getType()))
NewBECount = SE->getTruncateOrNoop(NewBECount,
BackedgeTakenCount->getType());
else
BackedgeTakenCount = SE->getTruncateOrNoop(BackedgeTakenCount,
NewBECount->getType());
assert(BackedgeTakenCount == NewBECount && "indvars must preserve SCEV");
}
#endif
return Changed; return Changed;
} }