[llvm] Coroutines: Cleanup typed pointer code in CoroFrame.cpp (PR #67141)

[via llvm-commits]

https://github.com/ruiling created https://github.com/llvm/llvm-project/pull/67141

None

>From 6e50e873027c663cc01c3a8538981a12db7ba941 Mon Sep 17 00:00:00 2001
From: Ruiling Song <ruiling.song at amd.com>
Date: Fri, 22 Sep 2023 22:00:29 +0800
Subject: [PATCH] Coroutines: Cleanup typed pointer code in CoroFrame.cpp

---
 llvm/lib/Transforms/Coroutines/CoroFrame.cpp | 34 +++-----------------
 1 file changed, 5 insertions(+), 29 deletions(-)

diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index 40b0650deda51e1..d6e5c6c03e5ff34 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -1682,15 +1682,6 @@ static Instruction *splitBeforeCatchSwitch(CatchSwitchInst *CatchSwitch) {
   return CleanupRet;
 }
 
-static void createFramePtr(coro::Shape &Shape) {
-  auto *CB = Shape.CoroBegin;
-  IRBuilder<> Builder(CB->getNextNode());
-  StructType *FrameTy = Shape.FrameTy;
-  PointerType *FramePtrTy = FrameTy->getPointerTo();
-  Shape.FramePtr =
-      cast<Instruction>(Builder.CreateBitCast(CB, FramePtrTy, "FramePtr"));
-}
-
 // Replace all alloca and SSA values that are accessed across suspend points
 // with GetElementPointer from coroutine frame + loads and stores. Create an
 // AllocaSpillBB that will become the new entry block for the resume parts of
@@ -1702,7 +1693,6 @@ static void createFramePtr(coro::Shape &Shape) {
 // becomes:
 //
 //    %hdl = coro.begin(...)
-//    %FramePtr = bitcast i8* hdl to %f.frame*
 //    br label %AllocaSpillBB
 //
 //  AllocaSpillBB:
@@ -1781,8 +1771,7 @@ static void insertSpills(const FrameDataInfo &FrameData, coro::Shape &Shape) {
     Type *ByValTy = nullptr;
     if (auto *Arg = dyn_cast<Argument>(Def)) {
       // For arguments, we will place the store instruction right after
-      // the coroutine frame pointer instruction, i.e. bitcast of
-      // coro.begin from i8* to %f.frame*.
+      // the coroutine frame pointer instruction, i.e. coro.begin.
       InsertPt = Shape.getInsertPtAfterFramePtr()->getIterator();
 
       // If we're spilling an Argument, make sure we clear 'nocapture'
@@ -1987,16 +1976,12 @@ static void insertSpills(const FrameDataInfo &FrameData, coro::Shape &Shape) {
     // to the pointer in the frame.
     for (const auto &Alias : A.Aliases) {
       auto *FramePtr = GetFramePointer(Alloca);
-      auto *FramePtrRaw =
-          Builder.CreateBitCast(FramePtr, Type::getInt8PtrTy(C));
       auto &Value = *Alias.second;
       auto ITy = IntegerType::get(C, Value.getBitWidth());
-      auto *AliasPtr = Builder.CreateGEP(Type::getInt8Ty(C), FramePtrRaw,
+      auto *AliasPtr = Builder.CreateGEP(Type::getInt8Ty(C), FramePtr,
                                          ConstantInt::get(ITy, Value));
-      auto *AliasPtrTyped =
-          Builder.CreateBitCast(AliasPtr, Alias.first->getType());
       Alias.first->replaceUsesWithIf(
-          AliasPtrTyped, [&](Use &U) { return DT.dominates(CB, U); });
+          AliasPtr, [&](Use &U) { return DT.dominates(CB, U); });
     }
   }
 
@@ -2769,17 +2754,8 @@ static void sinkLifetimeStartMarkers(Function &F, coro::Shape &Shape,
       // Sink lifetime.start markers to dominate block when they are
       // only used outside the region.
       if (Valid && Lifetimes.size() != 0) {
-        // May be AI itself, when the type of AI is i8*
-        auto *NewBitCast = [&](AllocaInst *AI) -> Value* {
-          if (isa<AllocaInst>(Lifetimes[0]->getOperand(1)))
-            return AI;
-          auto *Int8PtrTy = Type::getInt8PtrTy(F.getContext());
-          return CastInst::Create(Instruction::BitCast, AI, Int8PtrTy, "",
-                                  DomBB->getTerminator());
-        }(AI);
-
         auto *NewLifetime = Lifetimes[0]->clone();
-        NewLifetime->replaceUsesOfWith(NewLifetime->getOperand(1), NewBitCast);
+        NewLifetime->replaceUsesOfWith(NewLifetime->getOperand(1), AI);
         NewLifetime->insertBefore(DomBB->getTerminator());
 
         // All the outsided lifetime.start markers are no longer necessary.
@@ -3122,7 +3098,7 @@ void coro::buildCoroutineFrame(
       Shape.ABI == coro::ABI::Async)
     sinkSpillUsesAfterCoroBegin(F, FrameData, Shape.CoroBegin);
   Shape.FrameTy = buildFrameType(F, Shape, FrameData);
-  createFramePtr(Shape);
+  Shape.FramePtr = Shape.CoroBegin;
   // For now, this works for C++ programs only.
   buildFrameDebugInfo(F, Shape, FrameData);
   insertSpills(FrameData, Shape);