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[LoopIdiom] Use utility from SE instead of local rewriter 

ScalarEvolution::applyLoopGuards shall do the work.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D115784
This commit is contained in:
eopXD 2021-12-14 23:00:01 -08:00
parent e76043ac64
commit ecb3ae524e
1 changed files with 6 additions and 25 deletions
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31
llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
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@ -307,25 +307,6 @@ public:
}
};
// The Folder will fold expressions that are guarded by the loop entry.
class SCEVSignToZeroExtentionRewriter
: public SCEVRewriteVisitor<SCEVSignToZeroExtentionRewriter> {
public:
ScalarEvolution &SE;
const Loop *CurLoop;
SCEVSignToZeroExtentionRewriter(ScalarEvolution &SE, const Loop *CurLoop)
: SCEVRewriteVisitor(SE), SE(SE), CurLoop(CurLoop) {}
const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
// If expression is guarded by CurLoop to be greater or equal to zero
// then convert sext to zext. Otherwise return the original expression.
if (SE.isLoopEntryGuardedByCond(CurLoop, ICmpInst::ICMP_SGE, Expr,
SE.getZero(Expr->getType())))
return SE.getZeroExtendExpr(visit(Expr->getOperand()), Expr->getType());
return Expr;
}
};
} // end anonymous namespace
char LoopIdiomRecognizeLegacyPass::ID = 0;
@ -986,12 +967,12 @@ bool LoopIdiomRecognize::processLoopMemSet(MemSetInst *MSI,
<< "\n");
if (PositiveStrideSCEV != MemsetSizeSCEV) {
// The folding is to fold an expression that is covered by the loop guard
// at loop entry. After the folding, compare again and proceed with
// optimization, if equal.
SCEVSignToZeroExtentionRewriter Folder(*SE, CurLoop);
const SCEV *FoldedPositiveStride = Folder.visit(PositiveStrideSCEV);
const SCEV *FoldedMemsetSize = Folder.visit(MemsetSizeSCEV);
// If an expression is covered by the loop guard, compare again and
// proceed with optimization if equal.
const SCEV *FoldedPositiveStride =
SE->applyLoopGuards(PositiveStrideSCEV, CurLoop);
const SCEV *FoldedMemsetSize =
SE->applyLoopGuards(MemsetSizeSCEV, CurLoop);
LLVM_DEBUG(dbgs() << " Try to fold SCEV based on loop guard\n"
<< " FoldedMemsetSize: " << *FoldedMemsetSize << "\n"