[PATCH] D90689: [CodeExtractor] Replace uses of extracted bitcasts in out-of-region lifetime markers

[Giorgis Georgakoudis via Phabricator via llvm-commits]

ggeorgakoudis updated this revision to Diff 302598.
ggeorgakoudis added a comment.

Format better the patch message


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D90689/new/

https://reviews.llvm.org/D90689

Files:
  llvm/lib/Transforms/Utils/CodeExtractor.cpp


Index: llvm/lib/Transforms/Utils/CodeExtractor.cpp
===================================================================
--- llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -535,6 +535,46 @@
       continue;
     }
 
+    // Find bitcasts in the outlined region that have lifetime marker users
+    // outside that region. Replace the lifetime marker use with an
+    // outside region bitcast to avoid unnecessary alloca/reload instructions
+    // and extra lifetime markers.
+    SmallVector<Instruction *, 2> LifetimeBitcastUsers;
+    for (User *U : AI->users()) {
+      if(!definedInRegion(Blocks, U))
+        continue;
+
+      if (U->stripInBoundsConstantOffsets() != AI)
+        continue;
+
+      Instruction *Bitcast = cast<Instruction>(U);
+      for (User *BU : Bitcast->users()) {
+        IntrinsicInst *IntrInst = dyn_cast<IntrinsicInst>(BU);
+        if (!IntrInst)
+          continue;
+
+        if(!IntrInst->isLifetimeStartOrEnd())
+          continue;
+
+        if(definedInRegion(Blocks, IntrInst))
+          continue;
+
+        LLVM_DEBUG(dbgs() << "Replace use of extracted region bitcast"
+                          << *Bitcast << " in out-of-region lifetime marker "
+                          << *IntrInst << "\n");
+        LifetimeBitcastUsers.push_back(IntrInst);
+      }
+    }
+
+    for (Instruction *I : LifetimeBitcastUsers) {
+      Module *M = AIFunc->getParent();
+      LLVMContext &Ctx = M->getContext();
+      auto Int8PtrTy = Type::getInt8PtrTy(Ctx);
+      CastInst *CastI =
+          CastInst::CreatePointerCast(AI, Int8PtrTy, "lt.cast", I);
+      I->replaceUsesOfWith(I->getOperand(1), CastI);
+    }
+
     // Follow any bitcasts.
     SmallVector<Instruction *, 2> Bitcasts;
     SmallVector<LifetimeMarkerInfo, 2> BitcastLifetimeInfo;


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