Reapply r85634, with the bug fixed.

llvm-svn: 85655
This commit is contained in:
Dan Gohman 2009-10-31 14:22:52 +00:00
parent ba8735d25a
commit 930aa9d3d2
1 changed files with 17 additions and 15 deletions

View File

@ -10981,22 +10981,24 @@ Instruction *InstCombiner::visitPHINode(PHINode &PN) {
} }
} }
// Sort the PHI node operands to match the pred iterator order. This will // If there are multiple PHIs, sort their operands so that they all list
// help identical PHIs be eliminated by other passes. Other passes shouldn't // the blocks in the same order. This will help identical PHIs be eliminated
// depend on this for correctness however. // by other passes. Other passes shouldn't depend on this for correctness
unsigned i = 0; // however.
for (pred_iterator PI = pred_begin(PN.getParent()), PHINode *FirstPN = cast<PHINode>(PN.getParent()->begin());
PE = pred_end(PN.getParent()); PI != PE; ++PI, ++i) if (&PN != FirstPN)
if (PN.getIncomingBlock(i) != *PI) { for (unsigned i = 0, e = FirstPN->getNumIncomingValues(); i != e; ++i) {
unsigned j = PN.getBasicBlockIndex(*PI);
Value *VA = PN.getIncomingValue(i);
BasicBlock *BBA = PN.getIncomingBlock(i); BasicBlock *BBA = PN.getIncomingBlock(i);
Value *VB = PN.getIncomingValue(j); BasicBlock *BBB = FirstPN->getIncomingBlock(i);
BasicBlock *BBB = PN.getIncomingBlock(j); if (BBA != BBB) {
PN.setIncomingBlock(i, BBB); Value *VA = PN.getIncomingValue(i);
PN.setIncomingValue(i, VB); unsigned j = PN.getBasicBlockIndex(BBB);
PN.setIncomingBlock(j, BBA); Value *VB = PN.getIncomingValue(j);
PN.setIncomingValue(j, VA); PN.setIncomingBlock(i, BBB);
PN.setIncomingValue(i, VB);
PN.setIncomingBlock(j, BBA);
PN.setIncomingValue(j, VA);
}
} }
return 0; return 0;