[llvm-commits] [llvm] r58116 - in /llvm/trunk/lib/Target/PowerPC: PPCMachineFunctionInfo.h PPCRegisterInfo.cpp
Dale Johannesen
dalej at apple.com
Fri Oct 24 14:24:24 PDT 2008
Author: johannes
Date: Fri Oct 24 16:24:23 2008
New Revision: 58116
URL: http://llvm.org/viewvc/llvm-project?rev=58116&view=rev
Log:
Rewrite logic to figure out whether LR needs to
be saved/restored in the prolog/epilog. We need
to do this iff something in the function stores
into it.
Modified:
llvm/trunk/lib/Target/PowerPC/PPCMachineFunctionInfo.h
llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.cpp
Modified: llvm/trunk/lib/Target/PowerPC/PPCMachineFunctionInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCMachineFunctionInfo.h?rev=58116&r1=58115&r2=58116&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCMachineFunctionInfo.h (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCMachineFunctionInfo.h Fri Oct 24 16:24:23 2008
@@ -31,9 +31,10 @@
///
int ReturnAddrSaveIndex;
- /// UsesLR - Indicates whether LR is used in the current function. This is
- /// only valid after the initial scan of the function by PEI.
- bool UsesLR;
+ /// MustSaveLR - Indicates whether LR is defined (or clobbered) in the current
+ /// function. This is only valid after the initial scan of the function by
+ /// PEI.
+ bool MustSaveLR;
/// SpillsCR - Indicates whether CR is spilled in the current function.
bool SpillsCR;
@@ -79,12 +80,13 @@
int getTailCallSPDelta() const { return TailCallSPDelta; }
void setTailCallSPDelta(int size) { TailCallSPDelta = size; }
- /// UsesLR - This is set when the prolog/epilog inserter does its initial scan
- /// of the function, it is true if the LR/LR8 register is ever explicitly
- /// accessed/clobbered in the machine function (e.g. by calls and movpctolr,
- /// which is used in PIC generation).
- void setUsesLR(bool U) { UsesLR = U; }
- bool usesLR() const { return UsesLR; }
+ /// MustSaveLR - This is set when the prolog/epilog inserter does its initial
+ /// scan of the function. It is true if the LR/LR8 register is ever explicitly
+ /// defined/clobbered in the machine function (e.g. by calls and movpctolr,
+ /// which is used in PIC generation), or if the LR stack slot is explicitly
+ /// referenced by builtin_return_address.
+ void setMustSaveLR(bool U) { MustSaveLR = U; }
+ bool mustSaveLR() const { return MustSaveLR; }
void setSpillsCR() { SpillsCR = true; }
bool isCRSpilled() const { return SpillsCR; }
Modified: llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.cpp?rev=58116&r1=58115&r2=58116&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.cpp Fri Oct 24 16:24:23 2008
@@ -389,15 +389,15 @@
/// MustSaveLR - Return true if this function requires that we save the LR
/// register onto the stack in the prolog and restore it in the epilog of the
/// function.
-static bool MustSaveLR(const MachineFunction &MF) {
+static bool MustSaveLR(const MachineFunction &MF, unsigned LR) {
const PPCFunctionInfo *MFI = MF.getInfo<PPCFunctionInfo>();
- // We need an save/restore of LR if there is any use/def of LR explicitly, or
- // if there is some use of the LR stack slot (e.g. for builtin_return_address.
- return MFI->usesLR() || MFI->isLRStoreRequired() ||
- // FIXME: Anything that has a call should clobber the LR register,
- // isn't this redundant??
- MF.getFrameInfo()->hasCalls();
+ // We need a save/restore of LR if there is any def of LR (which is
+ // defined by calls, including the PIC setup sequence), or if there is
+ // some use of the LR stack slot (e.g. for builtin_return_address).
+ // (LR comes in 32 and 64 bit versions.)
+ MachineRegisterInfo::def_iterator RI = MF.getRegInfo().def_begin(LR);
+ return RI !=MF.getRegInfo().def_end() || MFI->isLRStoreRequired();
}
@@ -406,7 +406,7 @@
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (PerformTailCallOpt && I->getOpcode() == PPC::ADJCALLSTACKUP) {
- // Add (actually substract) back the amount the callee popped on return.
+ // Add (actually subtract) back the amount the callee popped on return.
if (int CalleeAmt = I->getOperand(1).getImm()) {
bool is64Bit = Subtarget.isPPC64();
CalleeAmt *= -1;
@@ -934,7 +934,7 @@
// Save and clear the LR state.
PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
unsigned LR = getRARegister();
- FI->setUsesLR(MF.getRegInfo().isPhysRegUsed(LR));
+ FI->setMustSaveLR(MustSaveLR(MF, LR));
MF.getRegInfo().setPhysRegUnused(LR);
// Save R31 if necessary
@@ -1015,8 +1015,9 @@
bool IsPPC64 = Subtarget.isPPC64();
// Get operating system
bool IsMachoABI = Subtarget.isMachoABI();
- // Check if the link register (LR) has been used.
- bool UsesLR = MustSaveLR(MF);
+ // Check if the link register (LR) must be saved.
+ PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
+ bool MustSaveLR = FI->mustSaveLR();
// Do we have a frame pointer for this function?
bool HasFP = hasFP(MF) && FrameSize;
@@ -1024,7 +1025,7 @@
int FPOffset = PPCFrameInfo::getFramePointerSaveOffset(IsPPC64, IsMachoABI);
if (IsPPC64) {
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::MFLR8), PPC::X0);
if (HasFP)
@@ -1033,13 +1034,13 @@
.addImm(FPOffset/4)
.addReg(PPC::X1);
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::STD))
.addReg(PPC::X0)
.addImm(LROffset / 4)
.addReg(PPC::X1);
} else {
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::MFLR), PPC::R0);
if (HasFP)
@@ -1048,7 +1049,7 @@
.addImm(FPOffset)
.addReg(PPC::R1);
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::STW))
.addReg(PPC::R0)
.addImm(LROffset)
@@ -1222,8 +1223,9 @@
bool IsPPC64 = Subtarget.isPPC64();
// Get operating system
bool IsMachoABI = Subtarget.isMachoABI();
- // Check if the link register (LR) has been used.
- bool UsesLR = MustSaveLR(MF);
+ // Check if the link register (LR) has been saved.
+ PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
+ bool MustSaveLR = FI->mustSaveLR();
// Do we have a frame pointer for this function?
bool HasFP = hasFP(MF) && FrameSize;
@@ -1237,8 +1239,6 @@
RetOpcode == PPC::TCRETURNdi8 ||
RetOpcode == PPC::TCRETURNai8;
- PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
-
if (UsesTCRet) {
int MaxTCRetDelta = FI->getTailCallSPDelta();
MachineOperand &StackAdjust = MBBI->getOperand(1);
@@ -1309,7 +1309,7 @@
}
if (IsPPC64) {
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::LD), PPC::X0)
.addImm(LROffset/4).addReg(PPC::X1);
@@ -1317,10 +1317,10 @@
BuildMI(MBB, MBBI, TII.get(PPC::LD), PPC::X31)
.addImm(FPOffset/4).addReg(PPC::X1);
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::MTLR8)).addReg(PPC::X0);
} else {
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::LWZ), PPC::R0)
.addImm(LROffset).addReg(PPC::R1);
@@ -1328,7 +1328,7 @@
BuildMI(MBB, MBBI, TII.get(PPC::LWZ), PPC::R31)
.addImm(FPOffset).addReg(PPC::R1);
- if (UsesLR)
+ if (MustSaveLR)
BuildMI(MBB, MBBI, TII.get(PPC::MTLR)).addReg(PPC::R0);
}
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