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Add support for spilling VRSAVE on PPC

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Although there is only one Altivec VRSAVE register, it is a member of
a register class, and we need the ability to spill it. Because this
register is normally callee-preserved and handled by special code this
has never before been necessary. However, this capability will be required by
a forthcoming commit adding SjLj support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177654 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-03-21 19:03:21 +00:00
parent e9cc0a09ae
commit 10f7f2a222
5 changed files with 124 additions and 1 deletions
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12
lib/Target/PowerPC/PPCInstrInfo.cpp
View File

@ -539,6 +539,12 @@ PPCInstrInfo::StoreRegToStackSlot(MachineFunction &MF,
getKillRegState(isKill)),
FrameIdx));
NonRI = true;
} else if (PPC::VRSAVERCRegClass.hasSubClassEq(RC)) {
NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::SPILL_VRSAVE))
.addReg(SrcReg,
getKillRegState(isKill)),
FrameIdx));
NonRI = true;
} else {
llvm_unreachable("Unknown regclass!");
}
@ -647,6 +653,12 @@ PPCInstrInfo::LoadRegFromStackSlot(MachineFunction &MF, DebugLoc DL,
NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LVX), DestReg),
FrameIdx));
NonRI = true;
} else if (PPC::VRSAVERCRegClass.hasSubClassEq(RC)) {
NewMIs.push_back(addFrameReference(BuildMI(MF, DL,
get(PPC::RESTORE_VRSAVE),
DestReg),
FrameIdx));
NonRI = true;
} else {
llvm_unreachable("Unknown regclass!");
}

23
lib/Target/PowerPC/PPCInstrInfo.td
View File

@ -1237,6 +1237,29 @@ def MFVRSAVE : XFXForm_1_ext<31, 339, 256, (outs GPRC:$rT), (ins),
"mfspr $rT, 256", IntGeneral>,
PPC970_DGroup_First, PPC970_Unit_FXU;
let isCodeGenOnly = 1 in {
def MTVRSAVEv : XFXForm_7_ext<31, 467, 256,
(outs VRSAVERC:$reg), (ins GPRC:$rS),
"mtspr 256, $rS", IntGeneral>,
PPC970_DGroup_Single, PPC970_Unit_FXU;
def MFVRSAVEv : XFXForm_1_ext<31, 339, 256, (outs GPRC:$rT),
(ins VRSAVERC:$reg),
"mfspr $rT, 256", IntGeneral>,
PPC970_DGroup_First, PPC970_Unit_FXU;
}
// SPILL_VRSAVE - Indicate that we're dumping the VRSAVE register,
// so we'll need to scavenge a register for it.
let mayStore = 1 in
def SPILL_VRSAVE : Pseudo<(outs), (ins VRSAVERC:$vrsave, memri:$F),
"#SPILL_VRSAVE", []>;
// RESTORE_VRSAVE - Indicate that we're restoring the VRSAVE register (previously
// spilled), so we'll need to scavenge a register for it.
let mayLoad = 1 in
def RESTORE_VRSAVE : Pseudo<(outs VRSAVERC:$vrsave), (ins memri:$F),
"#RESTORE_VRSAVE", []>;
def MTCRF : XFXForm_5<31, 144, (outs crbitm:$FXM), (ins GPRC:$rS),
"mtcrf $FXM, $rS", BrMCRX>,
PPC970_MicroCode, PPC970_Unit_CRU;

67
lib/Target/PowerPC/PPCRegisterInfo.cpp
View File

@ -369,6 +369,65 @@ void PPCRegisterInfo::lowerCRRestore(MachineBasicBlock::iterator II,
MBB.erase(II);
}
void PPCRegisterInfo::lowerVRSAVESpilling(MachineBasicBlock::iterator II,
unsigned FrameIndex, int SPAdj,
RegScavenger *RS) const {
// Get the instruction.
MachineInstr &MI = *II; // ; SPILL_VRSAVE <SrcReg>, <offset>
// Get the instruction's basic block.
MachineBasicBlock &MBB = *MI.getParent();
DebugLoc dl = MI.getDebugLoc();
// FIXME: Once LLVM supports creating virtual registers here, or the register
// scavenger can return multiple registers, stop using reserved registers
// here.
(void) SPAdj;
(void) RS;
unsigned Reg = PPC::R0;
unsigned SrcReg = MI.getOperand(0).getReg();
BuildMI(MBB, II, dl, TII.get(PPC::MFVRSAVEv), Reg)
.addReg(SrcReg, getKillRegState(MI.getOperand(0).isKill()));
addFrameReference(BuildMI(MBB, II, dl, TII.get(PPC::STW))
.addReg(Reg, getKillRegState(MI.getOperand(1).getImm())),
FrameIndex);
// Discard the pseudo instruction.
MBB.erase(II);
}
void PPCRegisterInfo::lowerVRSAVERestore(MachineBasicBlock::iterator II,
unsigned FrameIndex, int SPAdj,
RegScavenger *RS) const {
// Get the instruction.
MachineInstr &MI = *II; // ; <DestReg> = RESTORE_VRSAVE <offset>
// Get the instruction's basic block.
MachineBasicBlock &MBB = *MI.getParent();
DebugLoc dl = MI.getDebugLoc();
// FIXME: Once LLVM supports creating virtual registers here, or the register
// scavenger can return multiple registers, stop using reserved registers
// here.
(void) SPAdj;
(void) RS;
unsigned Reg = PPC::R0;
unsigned DestReg = MI.getOperand(0).getReg();
assert(MI.definesRegister(DestReg) &&
"RESTORE_VRSAVE does not define its destination");
addFrameReference(BuildMI(MBB, II, dl, TII.get(PPC::LWZ),
Reg), FrameIndex);
BuildMI(MBB, II, dl, TII.get(PPC::MTVRSAVEv), DestReg)
.addReg(Reg);
// Discard the pseudo instruction.
MBB.erase(II);
}
bool
PPCRegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
unsigned Reg, int &FrameIdx) const {
@ -429,13 +488,19 @@ PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
return;
}
// Special case for pseudo-ops SPILL_CR and RESTORE_CR.
// Special case for pseudo-ops SPILL_CR and RESTORE_CR, etc.
if (OpC == PPC::SPILL_CR) {
lowerCRSpilling(II, FrameIndex, SPAdj, RS);
return;
} else if (OpC == PPC::RESTORE_CR) {
lowerCRRestore(II, FrameIndex, SPAdj, RS);
return;
} else if (OpC == PPC::SPILL_VRSAVE) {
lowerVRSAVESpilling(II, FrameIndex, SPAdj, RS);
return;
} else if (OpC == PPC::RESTORE_VRSAVE) {
lowerVRSAVERestore(II, FrameIndex, SPAdj, RS);
return;
}
// Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).

5
lib/Target/PowerPC/PPCRegisterInfo.h
View File

@ -66,6 +66,11 @@ public:
int SPAdj, RegScavenger *RS) const;
void lowerCRRestore(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
void lowerVRSAVESpilling(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
void lowerVRSAVERestore(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
bool hasReservedSpillSlot(const MachineFunction &MF, unsigned Reg,
int &FrameIdx) const;
void eliminateFrameIndex(MachineBasicBlock::iterator II,

18
test/CodeGen/PowerPC/vrsave-spill.ll Normal file
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@ -0,0 +1,18 @@
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=g5 | FileCheck %s
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
define <4 x float> @foo(<4 x float> %a, <4 x float> %b) nounwind {
entry:
%c = fadd <4 x float> %a, %b
call void asm sideeffect "", "~{VRsave}"() nounwind
br label %return
; CHECK: @foo
; CHECK: mfspr {{[0-9]+}}, 256
; CHECK: mtspr 256, {{[0-9]+}}
return: ; preds = %entry
ret <4 x float> %c
}