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[LoopUnrollAnalyzer] Fix a crash in analyzeLoopUnrollCost. 

Condition might be simplified to a Constant, but it doesn't have to be
ConstantInt, so we should dyn_cast, instead of cast.

This fixes PR27886.

llvm-svn: 270924
This commit is contained in:
Michael Zolotukhin 2016-05-26 21:42:51 +00:00
parent 7509d54b21
commit 1ecdedad8d
2 changed files with 46 additions and 20 deletions
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36
llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
View File

@ -464,41 +464,37 @@ analyzeLoopUnrollCost(const Loop *L, unsigned TripCount, DominatorTree &DT,
// Add in the live successors by first checking whether we have terminator
// that may be simplified based on the values simplified by this call.
BasicBlock *KnownSucc = nullptr;
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
if (BI->isConditional()) {
if (Constant *SimpleCond =
SimplifiedValues.lookup(BI->getCondition())) {
BasicBlock *Succ = nullptr;
// Just take the first successor if condition is undef
if (isa<UndefValue>(SimpleCond))
Succ = BI->getSuccessor(0);
else
Succ = BI->getSuccessor(
cast<ConstantInt>(SimpleCond)->isZero() ? 1 : 0);
if (L->contains(Succ))
BBWorklist.insert(Succ);
else
ExitWorklist.insert({BB, Succ});
continue;
KnownSucc = BI->getSuccessor(0);
else if (ConstantInt *SimpleCondVal =
dyn_cast<ConstantInt>(SimpleCond))
KnownSucc = BI->getSuccessor(SimpleCondVal->isZero() ? 1 : 0);
}
}
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
if (Constant *SimpleCond =
SimplifiedValues.lookup(SI->getCondition())) {
BasicBlock *Succ = nullptr;
// Just take the first successor if condition is undef
if (isa<UndefValue>(SimpleCond))
Succ = SI->getSuccessor(0);
else
Succ = SI->findCaseValue(cast<ConstantInt>(SimpleCond))
.getCaseSuccessor();
if (L->contains(Succ))
BBWorklist.insert(Succ);
else
ExitWorklist.insert({BB, Succ});
continue;
KnownSucc = SI->getSuccessor(0);
else if (ConstantInt *SimpleCondVal =
dyn_cast<ConstantInt>(SimpleCond))
KnownSucc = SI->findCaseValue(SimpleCondVal).getCaseSuccessor();
}
}
if (KnownSucc) {
if (L->contains(KnownSucc))
BBWorklist.insert(KnownSucc);
else
ExitWorklist.insert({BB, KnownSucc});
continue;
}
// Add BB's successors to the worklist.
for (BasicBlock *Succ : successors(BB))

30
llvm/test/Transforms/LoopUnroll/full-unroll-crashers.ll
View File

@ -137,3 +137,33 @@ for.body:
exit:
ret void
}
@i = external global i32, align 4
define void @folded_not_to_constantint() {
entry:
br label %for.body
for.body:
%iv = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
%m = phi i32* [ @i, %entry ], [ %m, %for.inc ]
br i1 undef, label %if.else, label %if.then
if.then:
unreachable
if.else:
%cmp = icmp ult i32* %m, null
br i1 %cmp, label %cond.false, label %for.inc
cond.false:
unreachable
for.inc:
%inc = add nuw nsw i32 %iv, 1
%cmp2 = icmp ult i32 %inc, 10
br i1 %cmp2, label %for.body, label %for.end
for.end:
ret void
}