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Mark all PPC CR registers to be spilled as live-in and tag MFCR appropriately

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Leaving MFCR has having unmodeled side effects is not enough to prevent
unwanted instruction reordering post-RA. We could probably apply a stronger
barrier attribute, but there is a better way: Add all (not just the first) CR
to be spilled as live-in to the entry block, and add all CRs to the MFCR
instruction as implicitly killed.

Unfortunately, I don't have a small test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179465 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-04-13 23:06:15 +00:00
parent 41d59c6130
commit 63496f66c5
3 changed files with 16 additions and 15 deletions
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19
lib/Target/PowerPC/PPCFrameLowering.cpp
View File

@ -1122,18 +1122,21 @@ PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
*static_cast<const PPCInstrInfo*>(MF->getTarget().getInstrInfo()); *static_cast<const PPCInstrInfo*>(MF->getTarget().getInstrInfo());
DebugLoc DL; DebugLoc DL;
bool CRSpilled = false; bool CRSpilled = false;
MachineInstrBuilder CRMIB;
for (unsigned i = 0, e = CSI.size(); i != e; ++i) { for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg(); unsigned Reg = CSI[i].getReg();
// CR2 through CR4 are the nonvolatile CR fields. // CR2 through CR4 are the nonvolatile CR fields.
bool IsCRField = PPC::CR2 <= Reg && Reg <= PPC::CR4; bool IsCRField = PPC::CR2 <= Reg && Reg <= PPC::CR4;
if (CRSpilled && IsCRField)
continue;
// Add the callee-saved register as live-in; it's killed at the spill. // Add the callee-saved register as live-in; it's killed at the spill.
MBB.addLiveIn(Reg); MBB.addLiveIn(Reg);
if (CRSpilled && IsCRField) {
CRMIB.addReg(Reg, RegState::ImplicitKill);
continue;
}
// Insert the spill to the stack frame. // Insert the spill to the stack frame.
if (IsCRField) { if (IsCRField) {
CRSpilled = true; CRSpilled = true;
@ -1143,7 +1146,10 @@ PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
// 64-bit: SP+8 // 64-bit: SP+8
bool is31 = needsFP(*MF); bool is31 = needsFP(*MF);
unsigned FP8Reg = is31 ? PPC::X31 : PPC::X1; unsigned FP8Reg = is31 ? PPC::X31 : PPC::X1;
MBB.insert(MI, BuildMI(*MF, DL, TII.get(PPC::MFCR8), PPC::X12)); CRMIB = BuildMI(*MF, DL, TII.get(PPC::MFCR8), PPC::X12)
.addReg(Reg, RegState::ImplicitKill);
MBB.insert(MI, CRMIB);
MBB.insert(MI, BuildMI(*MF, DL, TII.get(PPC::STW8)) MBB.insert(MI, BuildMI(*MF, DL, TII.get(PPC::STW8))
.addReg(PPC::X12, .addReg(PPC::X12,
getKillRegState(true)) getKillRegState(true))
@ -1152,7 +1158,10 @@ PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
} else { } else {
// 32-bit: FP-relative. Note that we made sure CR2-CR4 all have // 32-bit: FP-relative. Note that we made sure CR2-CR4 all have
// the same frame index in PPCRegisterInfo::hasReservedSpillSlot. // the same frame index in PPCRegisterInfo::hasReservedSpillSlot.
MBB.insert(MI, BuildMI(*MF, DL, TII.get(PPC::MFCR), PPC::R12)); CRMIB = BuildMI(*MF, DL, TII.get(PPC::MFCR), PPC::R12)
.addReg(Reg, RegState::ImplicitKill);
MBB.insert(MI, CRMIB);
MBB.insert(MI, addFrameReference(BuildMI(*MF, DL, TII.get(PPC::STW)) MBB.insert(MI, addFrameReference(BuildMI(*MF, DL, TII.get(PPC::STW))
.addReg(PPC::R12, .addReg(PPC::R12,
getKillRegState(true)), getKillRegState(true)),

6
lib/Target/PowerPC/PPCInstr64Bit.td
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@ -256,11 +256,7 @@ def MFCR8pseud: XFXForm_3<31, 19, (outs G8RC:$rT), (ins crbitm:$FXM),
PPC970_MicroCode, PPC970_Unit_CRU; PPC970_MicroCode, PPC970_Unit_CRU;
} // neverHasSideEffects = 1 } // neverHasSideEffects = 1
// MFCR uses all CR registers, but marking that explicitly causes let neverHasSideEffects = 1 in
// problems because some of them appear to be undefined. Because
// this form is used only in prologue code, just mark it as having
// side effects.
let /* Uses = [CR0, CR1, CR2, CR3, CR4, CR5, CR6] */ hasSideEffects = 1 in
def MFCR8 : XFXForm_3<31, 19, (outs G8RC:$rT), (ins), def MFCR8 : XFXForm_3<31, 19, (outs G8RC:$rT), (ins),
"mfcr $rT", SprMFCR>, "mfcr $rT", SprMFCR>,
PPC970_MicroCode, PPC970_Unit_CRU; PPC970_MicroCode, PPC970_Unit_CRU;

6
lib/Target/PowerPC/PPCInstrInfo.td
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@ -1618,11 +1618,7 @@ def MFOCRF: XFXForm_5a<31, 19, (outs GPRC:$rT), (ins crbitm:$FXM),
PPC970_DGroup_First, PPC970_Unit_CRU; PPC970_DGroup_First, PPC970_Unit_CRU;
} // neverHasSideEffects = 1 } // neverHasSideEffects = 1
// MFCR uses all CR registers, but marking that explicitly causes let neverHasSideEffects = 1 in
// problems because some of them appear to be undefined. Because
// this form is used only in prologue code, just mark it as having
// side effects.
let /* Uses = [CR0, CR1, CR2, CR3, CR4, CR5, CR6] */ hasSideEffects = 1 in
def MFCR : XFXForm_3<31, 19, (outs GPRC:$rT), (ins), def MFCR : XFXForm_3<31, 19, (outs GPRC:$rT), (ins),
"mfcr $rT", SprMFCR>, "mfcr $rT", SprMFCR>,
PPC970_MicroCode, PPC970_Unit_CRU; PPC970_MicroCode, PPC970_Unit_CRU;