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Don't Place Entry Safepoints Before the llvm.frameescape() Intrinsic

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llvm.frameescape() intrinsic is not a real call. The intrinsic can only exist in the entry block. Inserting a gc.statepoint() before llvm.frameescape() may split the entry block, and push the intrinsic out of the entry block.

Patch by: Swaroop.Sridhar@microsoft.com
Differential Revision: http://reviews.llvm.org/D8910




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235820 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Philip Reames 2015-04-26 19:41:23 +00:00
parent ad82d26669
commit 83a049f2a6
2 changed files with 36 additions and 0 deletions
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7
lib/Transforms/Scalar/PlaceSafepoints.cpp
View File

@ -430,6 +430,13 @@ static Instruction *findLocationForEntrySafepoint(Function &F,
if (II->getIntrinsicID() == Intrinsic::assume) {
continue;
}
// llvm.frameescape() intrinsic is not a real call. The intrinsic can
// exist only in the entry block.
// Inserting a statepoint before llvm.frameescape() may split the
// entry block, and push the intrinsic out of the entry block.
if (II->getIntrinsicID() == Intrinsic::frameescape) {
continue;
}
}
break;
}

29
test/Transforms/PlaceSafepoints/statepoint-frameescape.ll Normal file
View File

@ -0,0 +1,29 @@
; RUN: opt %s -S -place-safepoints | FileCheck %s
declare void @llvm.frameescape(...)
; Do we insert the entry safepoint after the frameescape intrinsic?
define void @parent() gc "statepoint-example" {
; CHECK-LABEL: @parent
entry:
; CHECK-LABEL: entry
; CHECK-NEXT: alloca
; CHECK-NEXT: frameescape
; CHECK-NEXT: statepoint
%ptr = alloca i32
call void (...) @llvm.frameescape(i32* %ptr)
ret void
}
; This function is inlined when inserting a poll. To avoid recursive
; issues, make sure we don't place safepoints in it.
declare void @do_safepoint()
define void @gc.safepoint_poll() {
; CHECK-LABEL: gc.safepoint_poll
; CHECK-LABEL: entry
; CHECK-NEXT: do_safepoint
; CHECK-NEXT: ret void
entry:
call void @do_safepoint()
ret void
}