Temporarily revert r60195. It's causing an optimized bootstrap of llvm-gcc to fail.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60233 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 5fad309..c2f3209 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -240,30 +240,31 @@
/// their operands subsequently dead.
void LoopStrengthReduce::
DeleteTriviallyDeadInstructions(SetVector<Instruction*> &Insts) {
- SmallVector<Instruction*, 16> DeadInsts;
-
while (!Insts.empty()) {
Instruction *I = Insts.back();
Insts.pop_back();
-
- // If I is dead, delete it and all the things that it recursively uses
- // that become dead.
- RecursivelyDeleteTriviallyDeadInstructions(I, &DeadInsts);
-
- if (DeadInsts.empty()) continue;
- Changed = true;
- while (!DeadInsts.empty()) {
- Instruction *DeadInst = DeadInsts.back();
- DeadInsts.pop_back();
-
- // Make sure ScalarEvolutions knows this instruction is gone.
- SE->deleteValueFromRecords(DeadInst);
-
- // Make sure that this instruction is removed from DeadInsts if it was
- // recursively removed.
- if (DeadInst != I)
- Insts.remove(DeadInst);
+ if (PHINode *PN = dyn_cast<PHINode>(I)) {
+ // If all incoming values to the Phi are the same, we can replace the Phi
+ // with that value.
+ if (Value *PNV = PN->hasConstantValue()) {
+ if (Instruction *U = dyn_cast<Instruction>(PNV))
+ Insts.insert(U);
+ SE->deleteValueFromRecords(PN);
+ PN->replaceAllUsesWith(PNV);
+ PN->eraseFromParent();
+ Changed = true;
+ continue;
+ }
+ }
+
+ if (isInstructionTriviallyDead(I)) {
+ for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i)
+ if (Instruction *U = dyn_cast<Instruction>(*i))
+ Insts.insert(U);
+ SE->deleteValueFromRecords(I);
+ I->eraseFromParent();
+ Changed = true;
}
}
}