Simplify the logic of getting hold of a PHI predecessor block.

There is now a direct way from value-use-iterator to incoming block in PHINode's API.
This way we avoid the iterator->index->iterator trip, and especially the costly
getOperandNo() invocation. Additionally there is now an assertion that the iterator
really refers to one of the PHI's Uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62869 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 2 deletions

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 99fc7317b1..7f636c9270 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -988,8 +988,7 @@ static void ReplaceUsesOfMallocWithGlobal(Instruction *Alloc,
     } else if (PHINode *PN = dyn_cast<PHINode>(U)) {
       // Insert the load in the corresponding predecessor, not right before the
       // PHI.
-      unsigned PredNo = Alloc->use_begin().getOperandNo()/2;
-      InsertPt = PN->getIncomingBlock(PredNo)->getTerminator();
+      InsertPt = PN->getIncomingBlock(Alloc->use_begin())->getTerminator();
     } else if (isa<BitCastInst>(U)) {
       // Must be bitcast between the malloc and store to initialize the global.
       ReplaceUsesOfMallocWithGlobal(U, GV);