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Fix 12892.

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Dead code elimination during coalescing could cause a virtual register
to be split into connected components. The following rewriting would be
confused about the already joined copies present in the code, but
without a corresponding value number in the live range.

Erase all joined copies instantly when joining intervals such that the
MI and LiveInterval representations are always in sync.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157135 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-05-19 23:34:59 +00:00
parent 9012c57e18
commit 7ebed91fdd
3 changed files with 146 additions and 4 deletions
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4
lib/CodeGen/LiveRangeEdit.cpp
View File

@ -308,6 +308,10 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
TheDelegate->LRE_DidCloneVirtReg(Dups.back()->reg, LI->reg);
}
ConEQ.Distribute(&Dups[0], MRI);
DEBUG({
for (unsigned i = 0; i != NumComp; ++i)
dbgs() << '\t' << *Dups[i] << '\n';
});
}
}

24
lib/CodeGen/RegisterCoalescer.cpp
View File

@ -1081,9 +1081,10 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
if (!CP.isPhys() && RegClassInfo.isProperSubClass(CP.getNewRC()))
InflateRegs.push_back(CP.getDstReg());
// Remember to delete the copy instruction.
LIS->RemoveMachineInstrFromMaps(CopyMI);
CopyMI->eraseFromParent();
// CopyMI has been erased by joinIntervals at this point. Remove it from
// ErasedInstrs since copyCoalesceWorkList() won't add a successful join back
// to the work list. This keeps ErasedInstrs from growing needlessly.
ErasedInstrs.erase(CopyMI);
// Rewrite all SrcReg operands to DstReg.
// Also update DstReg operands to include DstIdx if it is set.
@ -1285,6 +1286,7 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
SmallVector<VNInfo*, 16> NewVNInfo;
SmallVector<MachineInstr*, 8> DupCopies;
SmallVector<MachineInstr*, 8> DeadCopies;
LiveInterval &LHS = LIS->getOrCreateInterval(CP.getDstReg());
DEBUG({ dbgs() << "\t\tLHS = "; LHS.print(dbgs(), TRI); dbgs() << "\n"; });
@ -1313,6 +1315,7 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
continue;
LHSValsDefinedFromRHS[VNI] = lr->valno;
DeadCopies.push_back(MI);
}
// Loop over the value numbers of the RHS, seeing if any are defined from
@ -1339,6 +1342,7 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
continue;
RHSValsDefinedFromLHS[VNI] = lr->valno;
DeadCopies.push_back(MI);
}
LHSValNoAssignments.resize(LHS.getNumValNums(), -1);
@ -1438,6 +1442,17 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
if (RHSValNoAssignments.empty())
RHSValNoAssignments.push_back(-1);
// Now erase all the redundant copies.
for (unsigned i = 0, e = DeadCopies.size(); i != e; ++i) {
MachineInstr *MI = DeadCopies[i];
DEBUG(dbgs() << "\t\terased:\t" << LIS->getInstructionIndex(MI)
<< '\t' << *MI);
if (!ErasedInstrs.insert(MI))
continue;
LIS->RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
}
SmallVector<unsigned, 8> SourceRegisters;
for (SmallVector<MachineInstr*, 8>::iterator I = DupCopies.begin(),
E = DupCopies.end(); I != E; ++I) {
@ -1451,7 +1466,8 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
// A = X
unsigned Src = MI->getOperand(1).getReg();
SourceRegisters.push_back(Src);
ErasedInstrs.insert(MI);
if (!ErasedInstrs.insert(MI))
continue;
LIS->RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
}

122
test/CodeGen/X86/2012-05-19-CoalescerCrash.ll Normal file
View File

@ -0,0 +1,122 @@
; RUN: llc < %s -verify-coalescing
; PR12892
;
; Dead code elimination during coalesing causes a live range to split into two
; virtual registers. Stale identity copies that had already been joined were
; interfering with the liveness computations.
target triple = "i386-pc-linux-gnu"
define void @_ZN4llvm17AsmMatcherEmitter3runERNS_11raw_ostreamE() align 2 {
invoke void @_ZNK4llvm13CodeGenTarget12getAsmParserEv()
to label %1 unwind label %5
; <label>:1 ; preds = %0
invoke void @_ZNK4llvm6Record16getValueAsStringENS_9StringRefE()
to label %4 unwind label %2
; <label>:2 ; preds = %1
%3 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
unreachable
; <label>:4 ; preds = %1
invoke void @_ZN4llvm18isCurrentDebugTypeEPKc()
to label %12 unwind label %7
; <label>:5 ; preds = %0
%6 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %33
; <label>:7 ; preds = %4
%8 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %9
; <label>:9 ; preds = %28, %7
%10 = phi { i8*, i32 } [ %29, %28 ], [ %8, %7 ]
%11 = extractvalue { i8*, i32 } %10, 1
invoke fastcc void @_ZN12_GLOBAL__N_114AsmMatcherInfoD2Ev()
to label %32 unwind label %35
; <label>:12 ; preds = %4
invoke void @_ZNK4llvm13CodeGenTarget10getRegBankEv()
to label %13 unwind label %16
; <label>:13 ; preds = %12
br label %14
; <label>:14 ; preds = %20, %13
%15 = icmp eq i32 undef, 0
br i1 %15, label %20, label %18
; <label>:16 ; preds = %12
%17 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %26
; <label>:18 ; preds = %14
invoke void @_ZNSs4_Rep9_S_createEjjRKSaIcE()
to label %19 unwind label %21
; <label>:19 ; preds = %18
unreachable
; <label>:20 ; preds = %14
br label %14
; <label>:21 ; preds = %18
%22 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
%23 = extractvalue { i8*, i32 } %22, 1
br i1 undef, label %26, label %24
; <label>:24 ; preds = %21
br i1 undef, label %25, label %26
; <label>:25 ; preds = %24
unreachable
; <label>:26 ; preds = %24, %21, %16
%27 = phi i32 [ 0, %16 ], [ %23, %21 ], [ %23, %24 ]
invoke void @_ZNSt6vectorISt4pairISsSsESaIS1_EED1Ev()
to label %28 unwind label %30
; <label>:28 ; preds = %26
%29 = insertvalue { i8*, i32 } undef, i32 %27, 1
br label %9
; <label>:30 ; preds = %26
%31 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
catch i8* null
unreachable
; <label>:32 ; preds = %9
br label %33
; <label>:33 ; preds = %32, %5
%34 = phi i32 [ undef, %5 ], [ %11, %32 ]
unreachable
; <label>:35 ; preds = %9
%36 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
catch i8* null
unreachable
}
declare void @_ZNK4llvm13CodeGenTarget12getAsmParserEv()
declare i32 @__gxx_personality_v0(...)
declare void @_ZNK4llvm6Record16getValueAsStringENS_9StringRefE()
declare void @_ZN4llvm18isCurrentDebugTypeEPKc()
declare fastcc void @_ZN12_GLOBAL__N_114AsmMatcherInfoD2Ev() unnamed_addr inlinehint align 2
declare hidden void @_ZNSt6vectorISt4pairISsSsESaIS1_EED1Ev() unnamed_addr align 2
declare void @_ZNSs4_Rep9_S_createEjjRKSaIcE()
declare void @_ZNK4llvm13CodeGenTarget10getRegBankEv()