[llvm-commits] [llvm] r70279 - in /llvm/trunk: lib/CodeGen/TwoAddressInstructionPass.cpp test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll
Evan Cheng
evan.cheng at apple.com
Mon Apr 27 19:12:36 PDT 2009
Author: evancheng
Date: Mon Apr 27 21:12:36 2009
New Revision: 70279
URL: http://llvm.org/viewvc/llvm-project?rev=70279&view=rev
Log:
Fix for PR4051. When 2address pass delete an instruction, update kill info when necessary.
Added:
llvm/trunk/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll
Modified:
llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp
Modified: llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp?rev=70279&r1=70278&r2=70279&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp (original)
+++ llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp Mon Apr 27 21:12:36 2009
@@ -88,6 +88,9 @@
bool NoUseAfterLastDef(unsigned Reg, MachineBasicBlock *MBB, unsigned Dist,
unsigned &LastDef);
+ MachineInstr *FindLastUseInMBB(unsigned Reg, MachineBasicBlock *MBB,
+ unsigned Dist);
+
bool isProfitableToCommute(unsigned regB, unsigned regC,
MachineInstr *MI, MachineBasicBlock *MBB,
unsigned Dist);
@@ -310,6 +313,28 @@
return !(LastUse > LastDef && LastUse < Dist);
}
+MachineInstr *TwoAddressInstructionPass::FindLastUseInMBB(unsigned Reg,
+ MachineBasicBlock *MBB,
+ unsigned Dist) {
+ unsigned LastUseDist = Dist;
+ MachineInstr *LastUse = 0;
+ for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(Reg),
+ E = MRI->reg_end(); I != E; ++I) {
+ MachineOperand &MO = I.getOperand();
+ MachineInstr *MI = MO.getParent();
+ if (MI->getParent() != MBB)
+ continue;
+ DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI);
+ if (DI == DistanceMap.end())
+ continue;
+ if (MO.isUse() && DI->second < LastUseDist) {
+ LastUse = DI->first;
+ LastUseDist = DI->second;
+ }
+ }
+ return LastUse;
+}
+
/// isCopyToReg - Return true if the specified MI is a copy instruction or
/// a extract_subreg instruction. It also returns the source and destination
/// registers and whether they are physical registers by reference.
@@ -684,7 +709,9 @@
/// isSafeToDelete - If the specified instruction does not produce any side
/// effects and all of its defs are dead, then it's safe to delete.
-static bool isSafeToDelete(MachineInstr *MI, const TargetInstrInfo *TII) {
+static bool isSafeToDelete(MachineInstr *MI, unsigned Reg,
+ const TargetInstrInfo *TII,
+ SmallVector<unsigned, 4> &Kills) {
const TargetInstrDesc &TID = MI->getDesc();
if (TID.mayStore() || TID.isCall())
return false;
@@ -693,10 +720,12 @@
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.isDef())
+ if (!MO.isReg())
continue;
- if (!MO.isDead())
+ if (MO.isDef() && !MO.isDead())
return false;
+ if (MO.isUse() && MO.getReg() != Reg && MO.isKill())
+ Kills.push_back(MO.getReg());
}
return true;
@@ -787,11 +816,53 @@
if (!isKilled(*mi, regB, MRI, TII)) {
// If regA is dead and the instruction can be deleted, just delete
// it so it doesn't clobber regB.
- if (mi->getOperand(ti).isDead() && isSafeToDelete(mi, TII)) {
- mbbi->erase(mi); // Nuke the old inst.
- mi = nmi;
- ++NumDeletes;
- break; // Done with this instruction.
+ SmallVector<unsigned, 4> Kills;
+ if (mi->getOperand(ti).isDead() &&
+ isSafeToDelete(mi, regB, TII, Kills)) {
+ SmallVector<std::pair<std::pair<unsigned, bool>
+ ,MachineInstr*>, 4> NewKills;
+ bool ReallySafe = true;
+ // If this instruction kills some virtual registers, we need
+ // update the kill information. If it's not possible to do so,
+ // then bail out.
+ while (!Kills.empty()) {
+ unsigned Kill = Kills.back();
+ Kills.pop_back();
+ if (TargetRegisterInfo::isPhysicalRegister(Kill)) {
+ ReallySafe = false;
+ break;
+ }
+ MachineInstr *LastKill = FindLastUseInMBB(Kill, &*mbbi, Dist);
+ if (LastKill) {
+ bool isModRef = LastKill->modifiesRegister(Kill);
+ NewKills.push_back(std::make_pair(std::make_pair(Kill,isModRef),
+ LastKill));
+ } else {
+ ReallySafe = false;
+ break;
+ }
+ }
+
+ if (ReallySafe) {
+ if (LV) {
+ while (!NewKills.empty()) {
+ MachineInstr *NewKill = NewKills.back().second;
+ unsigned Kill = NewKills.back().first.first;
+ bool isDead = NewKills.back().first.second;
+ NewKills.pop_back();
+ if (LV->removeVirtualRegisterKilled(Kill, mi)) {
+ if (isDead)
+ LV->addVirtualRegisterDead(Kill, NewKill);
+ else
+ LV->addVirtualRegisterKilled(Kill, NewKill);
+ }
+ }
+ }
+ mbbi->erase(mi); // Nuke the old inst.
+ mi = nmi;
+ ++NumDeletes;
+ break; // Done with this instruction.
+ }
}
// If this instruction is commutative, check to see if C dies. If
Added: llvm/trunk/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll?rev=70279&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll (added)
+++ llvm/trunk/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll Mon Apr 27 21:12:36 2009
@@ -0,0 +1,23 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin9
+; PR4051
+
+define void @int163(i32 %p_4, i32 %p_5) nounwind {
+entry:
+ %0 = tail call i32 @foo(i32 1) nounwind ; <i32> [#uses=2]
+ %1 = icmp eq i32 %0, 0 ; <i1> [#uses=1]
+ br i1 %1, label %bb.i, label %bar.exit
+
+bb.i: ; preds = %entry
+ %2 = lshr i32 1, %0 ; <i32> [#uses=1]
+ %3 = icmp eq i32 %2, 0 ; <i1> [#uses=1]
+ %retval.i = select i1 %3, i32 1, i32 %p_5 ; <i32> [#uses=1]
+ br label %bar.exit
+
+bar.exit: ; preds = %bb.i, %entry
+ %4 = phi i32 [ %retval.i, %bb.i ], [ %p_5, %entry ] ; <i32> [#uses=1]
+ %5 = icmp eq i32 %4, 0 ; <i1> [#uses=0]
+ %6 = tail call i32 @foo(i32 %p_5) nounwind ; <i32> [#uses=0]
+ ret void
+}
+
+declare i32 @foo(i32)
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