[NFC] BasicBlock: refactor changePhiUses() out of replacePhiUsesWith(), use it

Summary:
It is a common thing to loop over every `PHINode` in some `BasicBlock`
and change old `BasicBlock` incoming block to a new `BasicBlock` incoming block.
`replaceSuccessorsPhiUsesWith()` already had code to do that,
it just wasn't a function.
So outline it into a new function, and use it.

Reviewers: chandlerc, craig.topper, spatel, danielcdh

Reviewed By: craig.topper

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61013

llvm-svn: 359996

2 files changed, 10 insertions, 18 deletions

diff --git a/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp b/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
index 92e3e9a0496..64a97f86a21 100644
--- a/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
@@ -1325,8 +1325,7 @@ LoopConstrainer::RewrittenRangeInfo LoopConstrainer::changeIterationSpaceEnd(
 
   // The latch exit now has a branch from `RRI.ExitSelector' instead of
   // `LS.Latch'.  The PHI nodes need to be updated to reflect that.
-  for (PHINode &PN : LS.LatchExit->phis())
-    PN.replaceIncomingBlockWith(LS.Latch, RRI.ExitSelector);
+  LS.LatchExit->replacePhiUsesWith(LS.Latch, RRI.ExitSelector);
 
   return RRI;
 }
@@ -1349,8 +1348,7 @@ BasicBlock *LoopConstrainer::createPreheader(const LoopStructure &LS,
   BasicBlock *Preheader = BasicBlock::Create(Ctx, Tag, &F, LS.Header);
   BranchInst::Create(LS.Header, Preheader);
 
-  for (PHINode &PN : LS.Header->phis())
-    PN.replaceIncomingBlockWith(OldPreheader, Preheader);
+  LS.Header->replacePhiUsesWith(OldPreheader, Preheader);
 
   return Preheader;
 }
diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
index 8347dbe4598..bde4ecaaa6c 100644
--- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
@@ -1279,12 +1279,6 @@ static void moveBBContents(BasicBlock *FromBB, Instruction *InsertBefore) {
                 FromBB->getTerminator()->getIterator());
 }
 
-static void updateIncomingBlock(BasicBlock *CurrBlock, BasicBlock *OldPred,
-                                BasicBlock *NewPred) {
-  for (PHINode &PHI : CurrBlock->phis())
-    PHI.replaceIncomingBlockWith(OldPred, NewPred);
-}
-
 /// Update BI to jump to NewBB instead of OldBB. Records updates to
 /// the dominator tree in DTUpdates, if DT should be preserved.
 static void updateSuccessor(BranchInst *BI, BasicBlock *OldBB,
@@ -1349,7 +1343,7 @@ static void moveLCSSAPhis(BasicBlock *InnerExit, BasicBlock *InnerLatch,
   // Now adjust the incoming blocks for the LCSSA PHIs.
   // For PHIs moved from Inner's exit block, we need to replace Inner's latch
   // with the new latch.
-  updateIncomingBlock(InnerLatch, InnerLatch, OuterLatch);
+  InnerLatch->replacePhiUsesWith(InnerLatch, OuterLatch);
 }
 
 bool LoopInterchangeTransform::adjustLoopBranches() {
@@ -1416,8 +1410,8 @@ bool LoopInterchangeTransform::adjustLoopBranches() {
                   InnerLoopHeaderSuccessor, DTUpdates);
 
   // Adjust reduction PHI's now that the incoming block has changed.
-  updateIncomingBlock(InnerLoopHeaderSuccessor, InnerLoopHeader,
-                      OuterLoopHeader);
+  InnerLoopHeaderSuccessor->replacePhiUsesWith(InnerLoopHeader,
+                                               OuterLoopHeader);
 
   updateSuccessor(InnerLoopHeaderBI, InnerLoopHeaderSuccessor,
                   OuterLoopPreHeader, DTUpdates);
@@ -1449,7 +1443,7 @@ bool LoopInterchangeTransform::adjustLoopBranches() {
   moveLCSSAPhis(InnerLoopLatchSuccessor, InnerLoopLatch, OuterLoopLatch);
   // For PHIs in the exit block of the outer loop, outer's latch has been
   // replaced by Inners'.
-  updateIncomingBlock(OuterLoopLatchSuccessor, OuterLoopLatch, InnerLoopLatch);
+  OuterLoopLatchSuccessor->replacePhiUsesWith(OuterLoopLatch, InnerLoopLatch);
 
   // Now update the reduction PHIs in the inner and outer loop headers.
   SmallVector<PHINode *, 4> InnerLoopPHIs, OuterLoopPHIs;
@@ -1476,10 +1470,10 @@ bool LoopInterchangeTransform::adjustLoopBranches() {
   }
 
   // Update the incoming blocks for moved PHI nodes.
-  updateIncomingBlock(OuterLoopHeader, InnerLoopPreHeader, OuterLoopPreHeader);
-  updateIncomingBlock(OuterLoopHeader, InnerLoopLatch, OuterLoopLatch);
-  updateIncomingBlock(InnerLoopHeader, OuterLoopPreHeader, InnerLoopPreHeader);
-  updateIncomingBlock(InnerLoopHeader, OuterLoopLatch, InnerLoopLatch);
+  OuterLoopHeader->replacePhiUsesWith(InnerLoopPreHeader, OuterLoopPreHeader);
+  OuterLoopHeader->replacePhiUsesWith(InnerLoopLatch, OuterLoopLatch);
+  InnerLoopHeader->replacePhiUsesWith(OuterLoopPreHeader, InnerLoopPreHeader);
+  InnerLoopHeader->replacePhiUsesWith(OuterLoopLatch, InnerLoopLatch);
 
   return true;
 }