[llvm-branch-commits] [llvm] release/20.x: [CoroSplit] Always erase lifetime intrinsics for spilled allocas (#142551) (PR #147448)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/147448

Backport 038dc2c63b2db744be6afeea74b18be4938149e9

Requested by: @ChuanqiXu9

>From 13f1e8e095bfbe59ce537a911e6fe95d940961ba Mon Sep 17 00:00:00 2001
From: Weibo He <NewSigma at 163.com>
Date: Tue, 3 Jun 2025 18:52:41 +0800
Subject: [PATCH] [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 <yedeng.yd at linux.alibaba.com>
(cherry picked from commit 038dc2c63b2db744be6afeea74b18be4938149e9)
---
 llvm/lib/Transforms/Coroutines/CoroFrame.cpp | 21 +++++++++-----------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index 68edabb083be3..35832b594e9a3 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -1213,11 +1213,17 @@ 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);
@@ -1231,17 +1237,8 @@ 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) {