Fix a bug that was causing major slowdowns in povray. This was due to LCSSA
not handling PHI nodes correctly when determining if a value was live-out.
This patch reduces the number of detected live-out variables in the testcase
from 6565 to 485.
llvm-svn: 28771
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index ac540c9..37ab7ee 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -91,6 +91,7 @@
/// runOnFunction - Process all loops in the function, inner-most out.
bool LCSSA::runOnFunction(Function &F) {
bool changed = false;
+
LI = &getAnalysis<LoopInfo>();
DF = &getAnalysis<DominanceFrontier>();
DT = &getAnalysis<DominatorTree>();
@@ -107,7 +108,7 @@
bool LCSSA::visitSubloop(Loop* L) {
for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
visitSubloop(*I);
-
+
// Speed up queries by creating a sorted list of blocks
LoopBlocks.clear();
LoopBlocks.insert(LoopBlocks.end(), L->block_begin(), L->block_end());
@@ -162,7 +163,6 @@
phi = new PHINode(Instr->getType(), Instr->getName()+".lcssa",
(*BBI)->begin());
workList.push_back(cast<PHINode>(phi));
- Phis[*BBI] = phi;
}
}
@@ -253,6 +253,11 @@
for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E;
++UI) {
BasicBlock *UserBB = cast<Instruction>(*UI)->getParent();
+ if (PHINode* p = dyn_cast<PHINode>(*UI)) {
+ unsigned OperandNo = UI.getOperandNo();
+ UserBB = p->getIncomingBlock(OperandNo/2);
+ }
+
if (!inLoop(UserBB)) {
AffectedValues.insert(I);
break;