Add -verify-indvars for imperfect SCEV trip count verification after indvars.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139169 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2011-09-06 20:20:38 +00:00
parent 79d56a66c3
commit 75ebc0ec20

View File

@ -76,6 +76,13 @@ namespace llvm {
cl::opt<bool> DisableIVRewrite(
"disable-iv-rewrite", cl::Hidden,
cl::desc("Disable canonical induction variable rewriting"));
// Trip count verification can be enabled by default under NDEBUG if we
// implement a strong expression equivalence checker in SCEV. Until then, we
// use the verify-indvars flag, which may assert in some cases.
cl::opt<bool> VerifyIndvars(
"verify-indvars", cl::Hidden,
cl::desc("Verify the ScalarEvolution result after running indvars"));
}
// Temporary flag for use with -disable-iv-rewrite to force a canonical IV for
@ -1968,7 +1975,8 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
// 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)) {
if (DisableIVRewrite && VerifyIndvars &&
!isa<SCEVCouldNotCompute>(BackedgeTakenCount)) {
SE->forgetLoop(L);
const SCEV *NewBECount = SE->getBackedgeTakenCount(L);
if (SE->getTypeSizeInBits(BackedgeTakenCount->getType()) <