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Fix for PR14739. It's not safe to fold a load into a call across a store. Thanks to Nick Lewycky for the initial patch.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171665 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2013-01-06 19:00:15 +00:00
parent c6b4936a59
commit 700843ec2c
2 changed files with 26 additions and 4 deletions
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5
lib/Target/X86/X86ISelDAGToDAG.cpp
View File

@ -420,6 +420,11 @@ static bool isCalleeLoad(SDValue Callee, SDValue &Chain, bool HasCallSeq) {
if (!Chain.getNumOperands()) if (!Chain.getNumOperands())
return false; return false;
// Since we are not checking for AA here, conservatively abort if the chain
// writes to memory. It's not safe to move the callee (a load) across a store.
if (isa<MemSDNode>(Chain.getNode()) &&
cast<MemSDNode>(Chain.getNode())->writeMem())
return false;
if (Chain.getOperand(0).getNode() == Callee.getNode()) if (Chain.getOperand(0).getNode() == Callee.getNode())
return true; return true;
if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor && if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor &&

25
test/CodeGen/X86/fold-call.ll
View File

@ -1,10 +1,27 @@
; RUN: llc < %s -march=x86 | not grep mov ; RUN: llc < %s -march=x86 | FileCheck %s
; RUN: llc < %s -march=x86-64 | not grep mov ; RUN: llc < %s -march=x86-64 | FileCheck %s
; CHECK: test1
; CHECK-NOT: mov
declare void @bar() declare void @bar()
define void @test1(i32 %i0, i32 %i1, i32 %i2, i32 %i3, i32 %i4, i32 %i5, void()* %arg) nounwind {
define void @foo(i32 %i0, i32 %i1, i32 %i2, i32 %i3, i32 %i4, i32 %i5, void()* %arg) nounwind {
call void @bar() call void @bar()
call void %arg() call void %arg()
ret void ret void
} }
; PR14739
; CHECK: test2
; CHECK: mov{{.*}} $0, ([[REGISTER:%[a-z]+]])
; CHECK-NOT: jmp{{.*}} *([[REGISTER]])
%struct.X = type { void ()* }
define void @test2(%struct.X* nocapture %x) {
entry:
%f = getelementptr inbounds %struct.X* %x, i64 0, i32 0
%0 = load void ()** %f
store void ()* null, void ()** %f
tail call void %0()
ret void
}