Updates to support
* Changes in PHI node structure
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/DCE.cpp b/lib/Transforms/Scalar/DCE.cpp
index fbd852f..720354a 100644
--- a/lib/Transforms/Scalar/DCE.cpp
+++ b/lib/Transforms/Scalar/DCE.cpp
@@ -77,14 +77,14 @@
Instruction *I = BB->getInstList().front();
if (I->getInstType() != Instruction::PHINode) return false; // No PHI nodes
- cerr << "Killing PHIs from " << BB;
- cerr << "Pred #0 = " << *pred_begin(BB);
+ //cerr << "Killing PHIs from " << BB;
+ //cerr << "Pred #0 = " << *pred_begin(BB);
- cerr << "Method == " << BB->getParent();
+ //cerr << "Method == " << BB->getParent();
do {
PHINode *PN = (PHINode*)I;
- assert(PN->getOperand(1) == 0 && "PHI node should only have one value!");
+ assert(PN->getOperand(2) == 0 && "PHI node should only have one value!");
Value *V = PN->getOperand(0);
PN->replaceAllUsesWith(V); // Replace PHI node with its single value.
@@ -134,29 +134,25 @@
//
static void RemovePredecessorFromBlock(BasicBlock *BB, BasicBlock *Pred) {
pred_iterator PI(pred_begin(BB)), EI(pred_end(BB));
- unsigned pred_idx = 0, max_idx;
+ unsigned max_idx;
- cerr << "RPFB: " << Pred << "From Block: " << BB;
+ //cerr << "RPFB: " << Pred << "From Block: " << BB;
- // Find out what index the predecessor is...
- for (; *PI != BB; ++PI, ++pred_idx) {
- assert(PI != EI && "Pred is not a predecessor of BB!");
- }
-
// Loop over the rest of the predecssors until we run out, or until we find
// out that there are more than 2 predecessors.
- for (max_idx = pred_idx; PI != EI && max_idx < 2; ++PI, ++max_idx) /*empty*/;
+ for (max_idx = 0; PI != EI && max_idx < 3; ++PI, ++max_idx) /*empty*/;
// If there are exactly two predecessors, then we want to nuke the PHI nodes
// altogether.
- bool NukePHIs = max_idx == 1;
+ bool NukePHIs = max_idx == 2;
+ assert(max_idx != 0 && "PHI Node in block with 0 predecessors!?!?!");
// Okay, now we know that we need to remove predecessor #pred_idx from all
// PHI nodes. Iterate over each PHI node fixing them up
BasicBlock::InstListType::iterator II(BB->getInstList().begin());
for (; (*II)->getInstType() == Instruction::PHINode; ++II) {
PHINode *PN = (PHINode*)*II;
- PN->removeIncomingValue(pred_idx);
+ PN->removeIncomingValue(BB);
if (NukePHIs) { // Destroy the PHI altogether??
assert(PN->getOperand(1) == 0 && "PHI node should only have one value!");
@@ -282,7 +278,7 @@
BasicBlock::InstListType::iterator DI = Pred->getInstList().end();
assert(Pred->getTerminator() &&
"Degenerate basic block encountered!"); // Empty bb???
- delete Pred->getInstList().remove(--DI);
+ delete Pred->getInstList().remove(--DI); // Destroy uncond branch
// Move all definitions in the succecessor to the predecessor...
while (!BB->getInstList().empty()) {
@@ -290,12 +286,16 @@
Instruction *Def = BB->getInstList().remove(DI); // Remove from front
Pred->getInstList().push_back(Def); // Add to end...
}
-
+
// Remove basic block from the method... and advance iterator to the
// next valid block...
BB = BBs.remove(BBIt);
--BBIt; // remove puts us on the NEXT bb. We want the prev BB
Changed = true;
+
+ // Make all PHI nodes that refered to BB now refer to Pred as their
+ // source...
+ BB->replaceAllUsesWith(Pred);
// Inherit predecessors name if it exists...
if (BB->hasName() && !Pred->hasName()) Pred->setName(BB->getName());