[PATCH] D104051: [coro] Fix rematerializable instruction sinking to coro.suspend blocks

[Arnold Schwaighofer via Phabricator via llvm-commits]

aschwaighofer created this revision.
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There is a constraint that coro.suspend instructions need to be in their
own blocks. The coro split pass initially creates IR that obeys this constraint
(which is later checked). Sinking rematerializable instructions into these
blocks breaks that constraint.

Instead rematerialize in the predecessor block to the suspend's single
predecessor block.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D104051

Files:
  llvm/lib/Transforms/Coroutines/CoroFrame.cpp
  llvm/test/Transforms/Coroutines/coro-async.ll


Index: llvm/test/Transforms/Coroutines/coro-async.ll
===================================================================
--- llvm/test/Transforms/Coroutines/coro-async.ll
+++ llvm/test/Transforms/Coroutines/coro-async.ll
@@ -1,6 +1,6 @@
 ; RUN: opt < %s -enable-coroutines -O2 -S | FileCheck --check-prefixes=CHECK %s
 ; RUN: opt < %s -enable-coroutines -passes='default<O2>' -S | FileCheck --check-prefixes=CHECK %s
-
+; RUN: opt < %s -enable-coroutines -O0 -S
 target datalayout = "p:64:64:64"
 
 %async.task = type { i64 }
@@ -206,11 +206,12 @@
   store i8* %async.ctxt, i8** %callee_context.caller_context.addr
   %resume_proj_fun = bitcast i8*(i8*)* @resume_context_projection to i8*
   %callee = bitcast void(i8*, %async.task*, %async.actor*)* @asyncSuspend to i8*
+  %task.casted = bitcast i8* %arg0 to %async.task*
   %res = call {i8*, i8*, i8*} (i32, i8*, i8*, ...) @llvm.coro.suspend.async(i32 2,
                                                   i8* %resume.func_ptr,
                                                   i8* %resume_proj_fun,
                                                   void (i8*, i8*, %async.task*, %async.actor*)* @my_async_function.my_other_async_function_fp.apply,
-                                                  i8* %callee, i8* %callee_context, %async.task* %task, %async.actor *%actor), !dbg !9
+                                                  i8* %callee, i8* %callee_context, %async.task* %task.casted, %async.actor *%actor), !dbg !9
 
   %continuation_task_arg = extractvalue {i8*, i8*, i8*} %res, 0
   %task.2 =  bitcast i8* %continuation_task_arg to %async.task*
@@ -228,7 +229,7 @@
                                                   i8* %resume.func_ptr.1,
                                                   i8* %resume_proj_fun.2,
                                                   void (i8*, i8*, %async.task*, %async.actor*)* @my_async_function.my_other_async_function_fp.apply,
-                                                  i8* %callee.2, i8* %callee_context, %async.task* %task, %async.actor *%actor)
+                                                  i8* %callee.2, i8* %callee_context, %async.task* %task.casted, %async.actor *%actor)
 
   call void @llvm.coro.async.context.dealloc(i8* %callee_context)
   %continuation_actor_arg = extractvalue {i8*, i8*, i8*} %res.2, 1
@@ -536,6 +537,7 @@
 declare swiftcc void @asyncSuspend(i8*, %async.task*, %async.actor*)
 declare i8* @llvm.coro.async.resume()
 declare void @llvm.coro.async.size.replace(i8*, i8*)
+declare i8* @hide(i8*)
 
 !llvm.dbg.cu = !{!2}
 !llvm.module.flags = !{!0}
Index: llvm/lib/Transforms/Coroutines/CoroFrame.cpp
===================================================================
--- llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -1926,11 +1926,16 @@
     for (Instruction *U : E.second) {
       // If we have not seen this block, materialize the value.
       if (CurrentBlock != U->getParent()) {
-        CurrentBlock = U->getParent();
+
+        bool IsInCoroSuspendBlock = isa<AnyCoroSuspendInst>(U);
+        CurrentBlock = IsInCoroSuspendBlock
+                           ? U->getParent()->getSingleSuccessor()
+                           : U->getParent();
         CurrentMaterialization = cast<Instruction>(Def)->clone();
         CurrentMaterialization->setName(Def->getName());
         CurrentMaterialization->insertBefore(
-            &*CurrentBlock->getFirstInsertionPt());
+            IsInCoroSuspendBlock ? CurrentBlock->getTerminator()
+                                 : &*CurrentBlock->getFirstInsertionPt());
       }
       if (auto *PN = dyn_cast<PHINode>(U)) {
         assert(PN->getNumIncomingValues() == 1 &&


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