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Fix Transforms/IndVarsSimplify/2006-09-20-LFTR-Crash.ll

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30555 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-09-21 05:12:20 +00:00
parent 7ffc328e97
commit 9ba46c13bf
1 changed files with 22 additions and 15 deletions
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37
lib/Transforms/Scalar/IndVarSimplify.cpp
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@ -86,8 +86,8 @@ namespace {
void runOnLoop(Loop *L);
void EliminatePointerRecurrence(PHINode *PN, BasicBlock *Preheader,
std::set<Instruction*> &DeadInsts);
void LinearFunctionTestReplace(Loop *L, SCEV *IterationCount,
SCEVExpander &RW);
Instruction *LinearFunctionTestReplace(Loop *L, SCEV *IterationCount,
SCEVExpander &RW);
void RewriteLoopExitValues(Loop *L);
void DeleteTriviallyDeadInstructions(std::set<Instruction*> &Insts);
@ -209,13 +209,17 @@ void IndVarSimplify::EliminatePointerRecurrence(PHINode *PN,
/// variable. This pass is able to rewrite the exit tests of any loop where the
/// SCEV analysis can determine a loop-invariant trip count of the loop, which
/// is actually a much broader range than just linear tests.
void IndVarSimplify::LinearFunctionTestReplace(Loop *L, SCEV *IterationCount,
SCEVExpander &RW) {
///
/// This method returns a "potentially dead" instruction whose computation chain
/// should be deleted when convenient.
Instruction *IndVarSimplify::LinearFunctionTestReplace(Loop *L,
SCEV *IterationCount,
SCEVExpander &RW) {
// Find the exit block for the loop. We can currently only handle loops with
// a single exit.
std::vector<BasicBlock*> ExitBlocks;
L->getExitBlocks(ExitBlocks);
if (ExitBlocks.size() != 1) return;
if (ExitBlocks.size() != 1) return 0;
BasicBlock *ExitBlock = ExitBlocks[0];
// Make sure there is only one predecessor block in the loop.
@ -226,19 +230,17 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L, SCEV *IterationCount,
if (ExitingBlock == 0)
ExitingBlock = *PI;
else
return; // Multiple exits from loop to this block.
return 0; // Multiple exits from loop to this block.
}
assert(ExitingBlock && "Loop info is broken");
if (!isa<BranchInst>(ExitingBlock->getTerminator()))
return; // Can't rewrite non-branch yet
return 0; // Can't rewrite non-branch yet
BranchInst *BI = cast<BranchInst>(ExitingBlock->getTerminator());
assert(BI->isConditional() && "Must be conditional to be part of loop!");
std::set<Instruction*> InstructionsToDelete;
if (Instruction *Cond = dyn_cast<Instruction>(BI->getCondition()))
InstructionsToDelete.insert(Cond);
Instruction *PotentiallyDeadInst = dyn_cast<Instruction>(BI->getCondition());
// If the exiting block is not the same as the backedge block, we must compare
// against the preincremented value, otherwise we prefer to compare against
// the post-incremented value.
@ -279,8 +281,7 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L, SCEV *IterationCount,
BI->setCondition(Cond);
++NumLFTR;
Changed = true;
DeleteTriviallyDeadInstructions(InstructionsToDelete);
return PotentiallyDeadInst;
}
@ -471,7 +472,12 @@ void IndVarSimplify::runOnLoop(Loop *L) {
SCEVExpander Rewriter(*SE, *LI);
Rewriter.getOrInsertCanonicalInductionVariable(L,
IterationCount->getType());
LinearFunctionTestReplace(L, IterationCount, Rewriter);
if (Instruction *I = LinearFunctionTestReplace(L, IterationCount,
Rewriter)) {
std::set<Instruction*> InstructionsToDelete;
InstructionsToDelete.insert(I);
DeleteTriviallyDeadInstructions(InstructionsToDelete);
}
}
return;
}
@ -498,7 +504,8 @@ void IndVarSimplify::runOnLoop(Loop *L) {
Changed = true;
if (!isa<SCEVCouldNotCompute>(IterationCount))
LinearFunctionTestReplace(L, IterationCount, Rewriter);
if (Instruction *DI = LinearFunctionTestReplace(L, IterationCount,Rewriter))
DeadInsts.insert(DI);
// Now that we have a canonical induction variable, we can rewrite any
// recurrences in terms of the induction variable. Start with the auxillary