make instcombine's instruction sinking more aggressive in the
presence of PHI nodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84103 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 88421db..50d6d99 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -12836,7 +12836,15 @@
// See if we can trivially sink this instruction to a successor basic block.
if (I->hasOneUse()) {
BasicBlock *BB = I->getParent();
- BasicBlock *UserParent = cast<Instruction>(I->use_back())->getParent();
+ Instruction *UserInst = cast<Instruction>(I->use_back());
+ BasicBlock *UserParent;
+
+ // Get the block the use occurs in.
+ if (PHINode *PN = dyn_cast<PHINode>(UserInst))
+ UserParent = PN->getIncomingBlock(I->use_begin().getUse());
+ else
+ UserParent = UserInst->getParent();
+
if (UserParent != BB) {
bool UserIsSuccessor = false;
// See if the user is one of our successors.
@@ -12849,8 +12857,7 @@
// If the user is one of our immediate successors, and if that successor
// only has us as a predecessors (we'd have to split the critical edge
// otherwise), we can keep going.
- if (UserIsSuccessor && !isa<PHINode>(I->use_back()) &&
- next(pred_begin(UserParent)) == pred_end(UserParent))
+ if (UserIsSuccessor && UserParent->getSinglePredecessor())
// Okay, the CFG is simple enough, try to sink this instruction.
MadeIRChange |= TryToSinkInstruction(I, UserParent);
}