[llvm-commits] [llvm] r138932 - /llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
Bill Wendling
isanbard at gmail.com
Wed Aug 31 18:28:11 PDT 2011
Author: void
Date: Wed Aug 31 20:28:11 2011
New Revision: 138932
URL: http://llvm.org/viewvc/llvm-project?rev=138932&view=rev
Log:
Resubmit with fix. Properly remove the instructions except for landingpad, which should be removed only when its invokes are.
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=138932&r1=138931&r2=138932&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Wed Aug 31 20:28:11 2011
@@ -1574,22 +1574,41 @@
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (!Visited.count(BB)) {
Instruction *Term = BB->getTerminator();
- while (Term != BB->begin()) { // Remove instrs bottom-up
- BasicBlock::iterator I = Term; --I;
- DEBUG(errs() << "IC: DCE: " << *I << '\n');
+ if (isa<TerminatorInst>(BB->begin()))
+ continue;
+
+ // Delete the instructions backwards, as it has a reduced likelihood of
+ // having to update as many def-use and use-def chains.
+ std::vector<Instruction*> WorkList;
+ WorkList.reserve(BB->size());
+ BasicBlock::iterator I = Term; --I;
+
+ while (true) {
+ if (!I->getType()->isVoidTy())
+ I->replaceAllUsesWith(UndefValue::get(I->getType()));
+ WorkList.push_back(I);
+ if (I == BB->begin())
+ break;
+ --I;
+ }
+
+ for (std::vector<Instruction*>::iterator
+ II = WorkList.begin(), IE = WorkList.end(); II != IE; ++II) {
+ Instruction *Inst = *II;
+ // Don't remove the landing pad. It should be removed only when its
+ // invokes are removed.
+ if (isa<LandingPadInst>(Inst))
+ continue;
+
// A debug intrinsic shouldn't force another iteration if we weren't
// going to do one without it.
- if (!isa<DbgInfoIntrinsic>(I)) {
+ if (!isa<DbgInfoIntrinsic>(Inst)) {
++NumDeadInst;
MadeIRChange = true;
}
- // If I is not void type then replaceAllUsesWith undef.
- // This allows ValueHandlers and custom metadata to adjust itself.
- if (!I->getType()->isVoidTy())
- I->replaceAllUsesWith(UndefValue::get(I->getType()));
- I->eraseFromParent();
+ Inst->eraseFromParent();
}
}
}
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