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Fix a DAGCombiner optimization to respect volatile qualification.

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llvm-svn: 48994
This commit is contained in:
Dan Gohman 2008-03-31 20:32:52 +00:00
parent c2c2b45acb
commit f223eaafcd
2 changed files with 26 additions and 1 deletions
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3
lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -4387,7 +4387,8 @@ SDOperand DAGCombiner::visitLOAD(SDNode *N) {
// value.
// TODO: Handle store large -> read small portion.
// TODO: Handle TRUNCSTORE/LOADEXT
if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
if (LD->getExtensionType() == ISD::NON_EXTLOAD &&
!LD->isVolatile()) {
if (ISD::isNON_TRUNCStore(Chain.Val)) {
StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
if (PrevST->getBasePtr() == Ptr &&

24
test/CodeGen/X86/pr2182.ll Normal file
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@ -0,0 +1,24 @@
; RUN: llvm-as < %s | llc | grep {addl \$3, (%eax)} | count 4
; PR2182
target datalayout =
"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin8"
@x = weak global i32 0 ; <i32*> [#uses=8]
define void @loop_2() nounwind {
entry:
%tmp = volatile load i32* @x, align 4 ; <i32> [#uses=1]
%tmp1 = add i32 %tmp, 3 ; <i32> [#uses=1]
volatile store i32 %tmp1, i32* @x, align 4
%tmp.1 = volatile load i32* @x, align 4 ; <i32> [#uses=1]
%tmp1.1 = add i32 %tmp.1, 3 ; <i32> [#uses=1]
volatile store i32 %tmp1.1, i32* @x, align 4
%tmp.2 = volatile load i32* @x, align 4 ; <i32> [#uses=1]
%tmp1.2 = add i32 %tmp.2, 3 ; <i32> [#uses=1]
volatile store i32 %tmp1.2, i32* @x, align 4
%tmp.3 = volatile load i32* @x, align 4 ; <i32> [#uses=1]
%tmp1.3 = add i32 %tmp.3, 3 ; <i32> [#uses=1]
volatile store i32 %tmp1.3, i32* @x, align 4
ret void
}