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author | Dan Gohman <gohman@apple.com> | 2011-03-10 19:51:54 +0000 |
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committer | Dan Gohman <gohman@apple.com> | 2011-03-10 19:51:54 +0000 |
commit | fa0e6facc793d0a67e89f873e18cd35a9d7c02e0 (patch) | |
tree | 9992bf46d1cb90f5a7697ac748938115857b7f13 /lib | |
parent | a4f809d8db5222708c9f4519f48916cc919fd19f (diff) | |
download | external_llvm-fa0e6facc793d0a67e89f873e18cd35a9d7c02e0.tar.gz external_llvm-fa0e6facc793d0a67e89f873e18cd35a9d7c02e0.tar.bz2 external_llvm-fa0e6facc793d0a67e89f873e18cd35a9d7c02e0.zip |
Fix reassociate to postpone certain instruction deletions until
after it has finished all of its reassociations, because its
habit of unlinking operands and holding them in a datastructure
while working means that it's not easy to determine when an
instruction is really dead until after all its regular work is
done. rdar://9096268.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127424 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Transforms/Scalar/Reassociate.cpp | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/Reassociate.cpp b/lib/Transforms/Scalar/Reassociate.cpp index e093b52571..6a0fb3f778 100644 --- a/lib/Transforms/Scalar/Reassociate.cpp +++ b/lib/Transforms/Scalar/Reassociate.cpp @@ -22,6 +22,7 @@ #define DEBUG_TYPE "reassociate" #include "llvm/Transforms/Scalar.h" +#include "llvm/Transforms/Utils/Local.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" #include "llvm/Function.h" @@ -74,6 +75,7 @@ namespace { class Reassociate : public FunctionPass { DenseMap<BasicBlock*, unsigned> RankMap; DenseMap<AssertingVH<>, unsigned> ValueRankMap; + SmallVector<WeakVH, 8> DeadInsts; bool MadeChange; public: static char ID; // Pass identification, replacement for typeid @@ -113,13 +115,13 @@ FunctionPass *llvm::createReassociatePass() { return new Reassociate(); } void Reassociate::RemoveDeadBinaryOp(Value *V) { Instruction *Op = dyn_cast<Instruction>(V); - if (!Op || !isa<BinaryOperator>(Op) || !Op->use_empty()) + if (!Op || !isa<BinaryOperator>(Op)) return; Value *LHS = Op->getOperand(0), *RHS = Op->getOperand(1); ValueRankMap.erase(Op); - Op->eraseFromParent(); + DeadInsts.push_back(Op); RemoveDeadBinaryOp(LHS); RemoveDeadBinaryOp(RHS); } @@ -603,7 +605,7 @@ Value *Reassociate::RemoveFactorFromExpression(Value *V, Value *Factor) { // remaining operand. if (Factors.size() == 1) { ValueRankMap.erase(BO); - BO->eraseFromParent(); + DeadInsts.push_back(BO); V = Factors[0].Op; } else { RewriteExprTree(BO, Factors); @@ -1093,6 +1095,12 @@ bool Reassociate::runOnFunction(Function &F) { for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) ReassociateBB(FI); + // Now that we're done, delete any instructions which are no longer used. + while (!DeadInsts.empty()) + if (Instruction *Inst = + cast_or_null<Instruction>((Value *)DeadInsts.pop_back_val())) + RecursivelyDeleteTriviallyDeadInstructions(Inst); + // We are done with the rank map. RankMap.clear(); ValueRankMap.clear(); |