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[coroutines] Insert spills of PHI instructions correctly 

Summary:
Fix a bug where we were inserting a spill in between the PHIs in the beginning of the block.
Consider this fragment:

```
begin:
  %phi1 = phi i32 [ 0, %entry ], [ 2, %alt ]
  %phi2 = phi i32 [ 1, %entry ], [ 3, %alt ]
  %sp1 = call i8 @llvm.coro.suspend(token none, i1 false)
  switch i8 %sp1, label %suspend [i8 0, label %resume
                                  i8 1, label %cleanup]
resume:
  call i32 @print(i32 %phi1)
```
Unless we are spilling the argument or result of the invoke, we were always inserting the spill immediately following the instruction.
The fix adds a check that if the spilled instruction is a PHI Node, select an appropriate insert point with `getFirstInsertionPt()` that
skips all the PHI Nodes and EH pads.

Reviewers: majnemer, rnk

Reviewed By: rnk

Subscribers: qcolombet, EricWF, llvm-commits

Differential Revision: https://reviews.llvm.org/D31799

llvm-svn: 299771
This commit is contained in:
Gor Nishanov 2017-04-07 14:16:49 +00:00
parent 11fe2e9f2b
commit 138ad6c9c0
2 changed files with 64 additions and 0 deletions
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4
llvm/lib/Transforms/Coroutines/CoroFrame.cpp
View File

@ -435,6 +435,10 @@ static Instruction *insertSpills(SpillInfo &Spills, coro::Shape &Shape) {
// normal edge and insert the spill in the new block.
auto NewBB = SplitEdge(II->getParent(), II->getNormalDest());
InsertPt = NewBB->getTerminator();
} else if (dyn_cast<PHINode>(CurrentValue)) {
// Skip the PHINodes and EH pads instructions.
InsertPt =
&*cast<Instruction>(E.def())->getParent()->getFirstInsertionPt();
} else {
// For all other values, the spill is placed immediately after
// the definition.

60
llvm/test/Transforms/Coroutines/coro-spill-after-phi.ll Normal file
View File

@ -0,0 +1,60 @@
; Verifies that we insert spills of PHI instruction _after) all PHI Nodes
; RUN: opt < %s -coro-split -S | FileCheck %s
define i8* @f(i1 %n) "coroutine.presplit"="1" {
entry:
%id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
%size = call i32 @llvm.coro.size.i32()
%alloc = call i8* @malloc(i32 %size)
%hdl = call i8* @llvm.coro.begin(token %id, i8* %alloc)
br i1 %n, label %begin, label %alt
alt:
br label %begin
begin:
%phi1 = phi i32 [ 0, %entry ], [ 2, %alt ]
%phi2 = phi i32 [ 1, %entry ], [ 3, %alt ]
%sp1 = call i8 @llvm.coro.suspend(token none, i1 false)
switch i8 %sp1, label %suspend [i8 0, label %resume
i8 1, label %cleanup]
resume:
call i32 @print(i32 %phi1)
call i32 @print(i32 %phi2)
br label %cleanup
cleanup:
%mem = call i8* @llvm.coro.free(token %id, i8* %hdl)
call void @free(i8* %mem)
br label %suspend
suspend:
call i1 @llvm.coro.end(i8* %hdl, i1 0)
ret i8* %hdl
}
; Verifies that the both phis are stored correctly in the coroutine frame
; CHECK: %f.Frame = type { void (%f.Frame*)*, void (%f.Frame*)*, i1, i1, i32, i32 }
; CHECK-LABEL: @f(
; CHECK: store void (%f.Frame*)* @f.destroy, void (%f.Frame*)** %destroy.addr
; CHECK: %phi1 = select i1 %n, i32 0, i32 2
; CHECK: %phi2 = select i1 %n, i32 1, i32 3
; CHECK: %phi2.spill.addr = getelementptr inbounds %f.Frame, %f.Frame* %FramePtr, i32 0, i32 5
; CHECK: store i32 %phi2, i32* %phi2.spill.addr
; CHECK: %phi1.spill.addr = getelementptr inbounds %f.Frame, %f.Frame* %FramePtr, i32 0, i32 4
; CHECK: store i32 %phi1, i32* %phi1.spill.addr
; CHECK: ret i8* %hdl
declare i8* @llvm.coro.free(token, i8*)
declare i32 @llvm.coro.size.i32()
declare i8 @llvm.coro.suspend(token, i1)
declare void @llvm.coro.resume(i8*)
declare void @llvm.coro.destroy(i8*)
declare token @llvm.coro.id(i32, i8*, i8*, i8*)
declare i1 @llvm.coro.alloc(token)
declare i8* @llvm.coro.begin(token, i8*)
declare i1 @llvm.coro.end(i8*, i1)
declare noalias i8* @malloc(i32)
declare i32 @print(i32)
declare void @free(i8*)