[PATCH] D75345: [Coroutines][new pass manager] Move CoroElide pass to right position

[JunMa via Phabricator via llvm-commits]

junparser created this revision.
junparser added reviewers: modocache, wenlei.
Herald added subscribers: llvm-commits, hiraditya, EricWF.
Herald added a project: LLVM.

When test coroutines under new pass manager, we find that it is less powerful than legacy in coroutine frame elision.  
That's because CoroElide executed right after CoroSplit instead of after series of  optimization passes.

This patch move CoroElide same position as legacy

TestPlan: check-llvm, cppcoro


https://reviews.llvm.org/D75345

Files:
  llvm/lib/Passes/PassBuilder.cpp
  llvm/test/Transforms/Coroutines/ex2.ll
  llvm/test/Transforms/Coroutines/ex3.ll


Index: llvm/test/Transforms/Coroutines/ex3.ll
===================================================================
--- llvm/test/Transforms/Coroutines/ex3.ll
+++ llvm/test/Transforms/Coroutines/ex3.ll
@@ -6,11 +6,17 @@
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()
+  %need.dyn.alloc = call i1 @llvm.coro.alloc(token %id)
+  br i1 %need.dyn.alloc, label %dyn.alloc, label %coro.begin
+dyn.alloc:
   %alloc = call i8* @malloc(i32 %size)
-  %hdl = call noalias i8* @llvm.coro.begin(token %id, i8* %alloc)
+  br label %coro.begin
+coro.begin:
+  %phi = phi i8* [ null, %entry ], [ %alloc, %dyn.alloc ]
+  %hdl = call noalias i8* @llvm.coro.begin(token %id, i8* %phi)
   br label %loop
 loop:
-  %n.val = phi i32 [ %n, %entry ], [ %inc, %loop.resume ]
+  %n.val = phi i32 [ %n, %coro.begin ], [ %inc, %loop.resume ]
   call void @print(i32 %n.val) #4
   %0 = call i8 @llvm.coro.suspend(token none, i1 false)
   switch i8 %0, label %suspend [i8 0, label %loop.resume
@@ -37,8 +43,15 @@
   %hdl = call i8* @f(i32 4)
   call void @llvm.coro.resume(i8* %hdl)
   call void @llvm.coro.resume(i8* %hdl)
+  %c = ptrtoint i8* %hdl to i64
+  %to = icmp eq i64 %c, 0
+  br i1 %to, label %return, label %destroy
+destroy:
   call void @llvm.coro.destroy(i8* %hdl)
+  br label %return
+return:
   ret i32 0
+; CHECK-NOT:  i8* @malloc
 ; CHECK:      call void @print(i32 4)
 ; CHECK-NEXT: call void @print(i32 -5)
 ; CHECK-NEXT: call void @print(i32 5)
Index: llvm/test/Transforms/Coroutines/ex2.ll
===================================================================
--- llvm/test/Transforms/Coroutines/ex2.ll
+++ llvm/test/Transforms/Coroutines/ex2.ll
@@ -40,8 +40,14 @@
   %hdl = call i8* @f(i32 4)
   call void @llvm.coro.resume(i8* %hdl)
   call void @llvm.coro.resume(i8* %hdl)
+  %to = icmp eq i8* %hdl, null
+  br i1 %to, label %return, label %destroy
+destroy:
   call void @llvm.coro.destroy(i8* %hdl)
+  br label %return
+return:
   ret i32 0
+; CHECK-NOT:  call i8* @CustomAlloc
 ; CHECK:      call void @print(i32 4)
 ; CHECK-NEXT: call void @print(i32 5)
 ; CHECK-NEXT: call void @print(i32 6)
Index: llvm/lib/Passes/PassBuilder.cpp
===================================================================
--- llvm/lib/Passes/PassBuilder.cpp
+++ llvm/lib/Passes/PassBuilder.cpp
@@ -561,6 +561,9 @@
         EnableMSSALoopDependency, DebugLogging));
   }
 
+  if (PTO.Coroutines)
+    FPM.addPass(CoroElidePass());
+
   for (auto &C : ScalarOptimizerLateEPCallbacks)
     C(FPM, Level);
 
@@ -847,10 +850,8 @@
 
   MainCGPipeline.addPass(AttributorCGSCCPass());
 
-  if (PTO.Coroutines) {
+  if (PTO.Coroutines)
     MainCGPipeline.addPass(CoroSplitPass());
-    MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(CoroElidePass()));
-  }
 
   // Now deduce any function attributes based in the current code.
   MainCGPipeline.addPass(PostOrderFunctionAttrsPass());


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