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Coalescer should not delete copy instructions whose defs are partially dead. e.g.

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%RDI<def,dead> = MOV64rr %RAX<kill>, %EDI<imp-def>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100804 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-04-08 20:02:37 +00:00
parent b8db3c2c50
commit a57fabe815
4 changed files with 44 additions and 1 deletions
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4
include/llvm/CodeGen/MachineInstr.h
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@ -357,6 +357,10 @@ public:
/// return 0. /// return 0.
unsigned isConstantValuePHI() const; unsigned isConstantValuePHI() const;
/// allDefsAreDead - Return true if all the defs of this instruction are dead.
///
bool allDefsAreDead() const;
// //
// Debugging support // Debugging support
// //

13
lib/CodeGen/MachineInstr.cpp
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@ -1125,6 +1125,19 @@ unsigned MachineInstr::isConstantValuePHI() const {
return Reg; return Reg;
} }
/// allDefsAreDead - Return true if all the defs of this instruction are dead.
///
bool MachineInstr::allDefsAreDead() const {
for (unsigned i = 0, e = getNumOperands(); i < e; ++i) {
const MachineOperand &MO = getOperand(i);
if (!MO.isReg() || MO.isUse())
continue;
if (!MO.isDead())
return false;
}
return true;
}
void MachineInstr::dump() const { void MachineInstr::dump() const {
dbgs() << " " << *this; dbgs() << " " << *this;
} }

2
lib/CodeGen/SimpleRegisterCoalescing.cpp
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@ -2744,7 +2744,7 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
// delete them later. // delete them later.
DoDelete = false; DoDelete = false;
} }
if (MI->registerDefIsDead(DstReg)) { if (MI->allDefsAreDead()) {
LiveInterval &li = li_->getInterval(DstReg); LiveInterval &li = li_->getInterval(DstReg);
if (!ShortenDeadCopySrcLiveRange(li, MI)) if (!ShortenDeadCopySrcLiveRange(li, MI))
ShortenDeadCopyLiveRange(li, MI); ShortenDeadCopyLiveRange(li, MI);

26
test/CodeGen/X86/2010-04-08-CoalescerBug.ll Normal file
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@ -0,0 +1,26 @@
; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
; rdar://7842028
; Do not delete partially dead copy instructions.
; %RDI<def,dead> = MOV64rr %RAX<kill>, %EDI<imp-def>
; REP_MOVSD %ECX<imp-def,dead>, %EDI<imp-def,dead>, %ESI<imp-def,dead>, %ECX<imp-use,kill>, %EDI<imp-use,kill>, %ESI<imp-use,kill>
%struct.F = type { %struct.FC*, i32, i32, i8, i32, i32, i32 }
%struct.FC = type { [10 x i8], [32 x i32], %struct.FC*, i32 }
define void @t(%struct.F* %this) nounwind {
entry:
; CHECK: t:
; CHECK: addq $12, %rsi
%BitValueArray = alloca [32 x i32], align 4
%tmp2 = getelementptr inbounds %struct.F* %this, i64 0, i32 0
%tmp3 = load %struct.FC** %tmp2, align 8
%tmp4 = getelementptr inbounds %struct.FC* %tmp3, i64 0, i32 1, i64 0
%tmp5 = bitcast [32 x i32]* %BitValueArray to i8*
%tmp6 = bitcast i32* %tmp4 to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %tmp5, i8* %tmp6, i64 128, i32 4, i1 false)
unreachable
}
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind