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[LSR]: Fix cast to BranchInst.
AbandonedPublic

Authored by MarkGoncharovAl on Mar 20 2023, 4:31 AM.

Reviewers

Summary

getTerminator() returns Instruction*.
So, some tests (spec2006.483.xalancbmk) fail with SegFault, because we should cast more carefully.

Also, TODO is already implemented.

Change looks fine, but is missing a test case.

This revision now requires changes to proceed.Mar 20 2023, 4:33 AM

I landed a fix for this in 00fdd2cb6c55744ae21f18c377854e9359273454. This patch can be abandoned.

This patch has been landed

Path

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llvm/

lib/

Transforms/

Scalar/

9 lines

Show First 20 Lines • Show All 6,695 Lines • ▼ Show 20 Lines	canFoldTermCondOfLoop(Loop *L, ScalarEvolution &SE, DominatorTree &DT,

if (!SE.hasLoopInvariantBackedgeTakenCount(L)) {		if (!SE.hasLoopInvariantBackedgeTakenCount(L)) {
LLVM_DEBUG(dbgs() << "Cannot fold on backedge that is loop variant\n");		LLVM_DEBUG(dbgs() << "Cannot fold on backedge that is loop variant\n");
return std::nullopt;		return std::nullopt;
}		}

BasicBlock *LoopLatch = L->getLoopLatch();		BasicBlock *LoopLatch = L->getLoopLatch();

// TODO: Can we do something for greater than and less than?		BranchInst *BI = dyn_cast<BranchInst>(LoopLatch->getTerminator());
// Terminating condition is foldable when it is an eq/ne icmp		if (!BI \|\| BI->isUnconditional()) {
BranchInst *BI = cast<BranchInst>(LoopLatch->getTerminator());		LLVM_DEBUG(dbgs() << "Cannot fold terminator that is not a conditional "
if (BI->isUnconditional())		"branch instruction")
return std::nullopt;		return std::nullopt;
		}
auto *TermCond = dyn_cast<ICmpInst>(BI->getCondition());		auto *TermCond = dyn_cast<ICmpInst>(BI->getCondition());
if (!TermCond) {		if (!TermCond) {
LLVM_DEBUG(		LLVM_DEBUG(
dbgs() << "Cannot fold on branching condition that is not an ICmpInst");		dbgs() << "Cannot fold on branching condition that is not an ICmpInst");
return std::nullopt;		return std::nullopt;
}		}
if (!TermCond->hasOneUse()) {		if (!TermCond->hasOneUse()) {
LLVM_DEBUG(		LLVM_DEBUG(
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