[CoroSplit] Always erase lifetime intrinsics for spilled allocas (#142551)

If the control flow between `lifetime.start` and `lifetime.end` is too
complex, it is acceptable to give up the optimization opportunity and
collect the alloca to the frame. However, storing to the frame will
lengthen the lifetime of the alloca, and the sanitizer will complain. I
propose we always erase lifetime intrinsics of spilled allocas.

Fix #124612

---------

Co-authored-by: Chuanqi Xu <[email protected]>

Author: NewSigma

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -1215,11 +1215,17 @@ static void insertSpills(const FrameDataInfo &FrameData, coro::Shape &Shape) {
   for (const auto &A : FrameData.Allocas) {
     AllocaInst *Alloca = A.Alloca;
     UsersToUpdate.clear();
-    for (User *U : Alloca->users()) {
+    for (User *U : make_early_inc_range(Alloca->users())) {
       auto *I = cast<Instruction>(U);
-      if (DT.dominates(Shape.CoroBegin, I))
+      // It is meaningless to retain the lifetime intrinsics refer for the
+      // member of coroutine frames and the meaningless lifetime intrinsics
+      // are possible to block further optimizations.
+      if (I->isLifetimeStartOrEnd())
+        I->eraseFromParent();
+      else if (DT.dominates(Shape.CoroBegin, I))
         UsersToUpdate.push_back(I);
     }
+
     if (UsersToUpdate.empty())
       continue;
     auto *G = GetFramePointer(Alloca);
@@ -1233,17 +1239,8 @@ static void insertSpills(const FrameDataInfo &FrameData, coro::Shape &Shape) {
     for (auto *DVR : DbgVariableRecords)
       DVR->replaceVariableLocationOp(Alloca, G);
 
-    for (Instruction *I : UsersToUpdate) {
-      // It is meaningless to retain the lifetime intrinsics refer for the
-      // member of coroutine frames and the meaningless lifetime intrinsics
-      // are possible to block further optimizations.
-      if (I->isLifetimeStartOrEnd()) {
-        I->eraseFromParent();
-        continue;
-      }
-
+    for (Instruction *I : UsersToUpdate)
       I->replaceUsesOfWith(Alloca, G);
-    }
   }
   Builder.SetInsertPoint(&*Shape.getInsertPtAfterFramePtr());
   for (const auto &A : FrameData.Allocas) {