[PATCH] D85037: [LCSSA] Use IRBuilder for PHI creation.

[Florian Hahn via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGa9b06a2c14f9: [LCSSA] Use IRBuilder for PHI creation. (authored by fhahn).

Changed prior to commit:
  https://reviews.llvm.org/D85037?vs=282260&id=282406#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85037/new/

https://reviews.llvm.org/D85037

Files:
  llvm/include/llvm/Transforms/Utils/LoopUtils.h
  llvm/lib/Transforms/Utils/LCSSA.cpp
  llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp


Index: llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
===================================================================
--- llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -1951,11 +1951,8 @@
     // a defining loop. Fix LCSSA from for each operand of the new instruction,
     // if required.
     for (unsigned OpIdx = 0, OpEnd = Inst->getNumOperands(); OpIdx != OpEnd;
-         OpIdx++) {
-      auto *V = fixupLCSSAFormFor(Inst, OpIdx);
-      if (V != I)
-        DoInsert(V);
-    }
+         OpIdx++)
+      fixupLCSSAFormFor(Inst, OpIdx);
   }
 }
 
@@ -2540,7 +2537,7 @@
     return OpV;
 
   ToUpdate.push_back(OpI);
-  formLCSSAForInstructions(ToUpdate, SE.DT, SE.LI, &SE);
+  formLCSSAForInstructions(ToUpdate, SE.DT, SE.LI, &SE, Builder);
   return User->getOperand(OpIdx);
 }
 
Index: llvm/lib/Transforms/Utils/LCSSA.cpp
===================================================================
--- llvm/lib/Transforms/Utils/LCSSA.cpp
+++ llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -40,6 +40,7 @@
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/PredIteratorCache.h"
@@ -77,12 +78,15 @@
 /// rewrite the uses.
 bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
                                     const DominatorTree &DT, const LoopInfo &LI,
-                                    ScalarEvolution *SE) {
+                                    ScalarEvolution *SE,
+                                    IRBuilderBase &Builder) {
   SmallVector<Use *, 16> UsesToRewrite;
   SmallSetVector<PHINode *, 16> PHIsToRemove;
   PredIteratorCache PredCache;
   bool Changed = false;
 
+  IRBuilderBase::InsertPointGuard InsertPtGuard(Builder);
+
   // Cache the Loop ExitBlocks across this loop.  We expect to get a lot of
   // instructions within the same loops, computing the exit blocks is
   // expensive, and we're not mutating the loop structure.
@@ -151,9 +155,9 @@
       // If we already inserted something for this BB, don't reprocess it.
       if (SSAUpdate.HasValueForBlock(ExitBB))
         continue;
-
-      PHINode *PN = PHINode::Create(I->getType(), PredCache.size(ExitBB),
-                                    I->getName() + ".lcssa", &ExitBB->front());
+      Builder.SetInsertPoint(&ExitBB->front());
+      PHINode *PN = Builder.CreatePHI(I->getType(), PredCache.size(ExitBB),
+                                      I->getName() + ".lcssa");
       // Get the debug location from the original instruction.
       PN->setDebugLoc(I->getDebugLoc());
       // Add inputs from inside the loop for this PHI.
@@ -369,7 +373,9 @@
       Worklist.push_back(&I);
     }
   }
-  Changed = formLCSSAForInstructions(Worklist, DT, *LI, SE);
+
+  IRBuilder<> Builder(L.getHeader()->getContext());
+  Changed = formLCSSAForInstructions(Worklist, DT, *LI, SE, Builder);
 
   // If we modified the code, remove any caches about the loop from SCEV to
   // avoid dangling entries.
Index: llvm/include/llvm/Transforms/Utils/LoopUtils.h
===================================================================
--- llvm/include/llvm/Transforms/Utils/LoopUtils.h
+++ llvm/include/llvm/Transforms/Utils/LoopUtils.h
@@ -76,7 +76,7 @@
 /// Returns true if any modifications are made.
 bool formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
                               const DominatorTree &DT, const LoopInfo &LI,
-                              ScalarEvolution *SE);
+                              ScalarEvolution *SE, IRBuilderBase &Builder);
 
 /// Put loop into LCSSA form.
 ///


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