[PATCH] D99227: [Coroutine][Clang] Force emit lifetime intrinsics for Coroutines

Tue Mar 23 19:58:41 PDT 2021

ChuanqiXu added a comment.

Only one problem I had for emitting lifetime markers even at O0 is that would action make allocas to be optimized even at O0? If so, I wonder if it confuses programmers since they may find some variables disappear surprisingly. Or there would be no optimization since every function would be marked with option attribute. I am not sure about this.

If I understand this problem correctly, this patch could fix problems for the return value of symmetric transfer and the gro that we discussed in D98638 <https://reviews.llvm.org/D98638>. Then D98638 <https://reviews.llvm.org/D98638> may be unneeded. I prefer the implementation in this patch.

================
Comment at: clang/lib/CodeGen/CGDecl.cpp:1318
 /// otherwise
 llvm::Value *CodeGenFunction::EmitLifetimeStart(uint64_t Size,
                                                 llvm::Value *Addr) {
----------------
Can we sure frontend would always call this API to emit lifetime start? I mean the frontend may call EmitIntrinsic or create lifetime.start intrinsic directly whether by IRBuilder::CreateXXX or Instrinsic::Create(...). I worry about if this would incur changes out of design.

Then if we add check in EmitLifetimeStart, why not we add check in EmitLfietimeEnd?

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99227/new/

https://reviews.llvm.org/D99227