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Model inline asm constraint which ties an input to an output register as machine operand TIED_TO constraint. This eliminated the need to pre-allocate registers for these. This also allows register allocator can eliminate the unneeded copies.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67512 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2009-03-23 08:01:15 +00:00
parent 7d6d4b360f
commit fb11288109
10 changed files with 144 additions and 53 deletions
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15
include/llvm/InlineAsm.h
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@ -135,14 +135,13 @@ public:
return (Flag & 0xffff) >> 3;
}
/// isOutputOperandTiedToUse - Return true if the flag of the inline asm
/// operand indicates it is an output that's matched to an input operand.
static bool isOutputOperandTiedToUse(unsigned Flag, unsigned &UseIdx) {
if (Flag & 0x80000000) {
UseIdx = Flag >> 16;
return true;
}
return false;
/// isUseOperandTiedToDef - Return true if the flag of the inline asm
/// operand indicates it is an use operand that's matched to a def operand.
static bool isUseOperandTiedToDef(unsigned Flag, unsigned &Idx) {
if ((Flag & 0x80000000) == 0)
return false;
Idx = (Flag & ~0x80000000) >> 16;
return true;
}

10
lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -477,8 +477,8 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
assert(interval.containsOneValue());
unsigned DefIndex = getDefIndex(interval.getValNumInfo(0)->def);
unsigned RedefIndex = getDefIndex(MIIdx);
// It cannot be an early clobber MO.
assert(!MO.isEarlyClobber() && "Unexpected early clobber!");
if (MO.isEarlyClobber())
RedefIndex = getUseIndex(MIIdx);
const LiveRange *OldLR = interval.getLiveRangeContaining(RedefIndex-1);
VNInfo *OldValNo = OldLR->valno;
@ -499,6 +499,8 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
// Value#0 is now defined by the 2-addr instruction.
OldValNo->def = RedefIndex;
OldValNo->copy = 0;
if (MO.isEarlyClobber())
OldValNo->redefByEC = true;
// Add the new live interval which replaces the range for the input copy.
LiveRange LR(DefIndex, RedefIndex, ValNo);
@ -546,8 +548,8 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
// live until the end of the block. We've already taken care of the
// rest of the live range.
unsigned defIndex = getDefIndex(MIIdx);
// It cannot be an early clobber MO.
assert(!MO.isEarlyClobber() && "Unexpected early clobber!");
if (MO.isEarlyClobber())
defIndex = getUseIndex(MIIdx);
VNInfo *ValNo;
MachineInstr *CopyMI = NULL;

61
lib/CodeGen/MachineInstr.cpp
View File

@ -11,8 +11,9 @@
//
//===----------------------------------------------------------------------===//
#include "llvm/Constants.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Constants.h"
#include "llvm/InlineAsm.h"
#include "llvm/Value.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
@ -692,6 +693,35 @@ int MachineInstr::findFirstPredOperandIdx() const {
/// isRegReDefinedByTwoAddr - Given the index of a register operand,
/// check if the register def is a re-definition due to two addr elimination.
bool MachineInstr::isRegReDefinedByTwoAddr(unsigned DefIdx) const{
if (getOpcode() == TargetInstrInfo::INLINEASM) {
assert(DefIdx >= 2);
const MachineOperand &MO = getOperand(DefIdx);
if (!MO.isReg() || !MO.isDef())
return false;
// Determine the actual operand no corresponding to this index.
unsigned DefNo = 0;
for (unsigned i = 1, e = getNumOperands(); i < e; ) {
const MachineOperand &FMO = getOperand(i);
assert(FMO.isImm());
// Skip over this def.
i += InlineAsm::getNumOperandRegisters(FMO.getImm()) + 1;
if (i > DefIdx)
break;
++DefNo;
}
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
const MachineOperand &FMO = getOperand(i);
if (!FMO.isImm())
continue;
if (i+1 >= e || !getOperand(i+1).isReg() || !getOperand(i+1).isUse())
continue;
unsigned Idx;
if (InlineAsm::isUseOperandTiedToDef(FMO.getImm(), Idx) &&
Idx == DefNo)
return true;
}
}
assert(getOperand(DefIdx).isDef() && "DefIdx is not a def!");
const TargetInstrDesc &TID = getDesc();
for (unsigned i = 0, e = TID.getNumOperands(); i != e; ++i) {
@ -707,6 +737,35 @@ bool MachineInstr::isRegReDefinedByTwoAddr(unsigned DefIdx) const{
/// is a register use and it is tied to an def operand. It also returns the def
/// operand index by reference.
bool MachineInstr::isRegTiedToDefOperand(unsigned UseOpIdx, unsigned *DefOpIdx){
if (getOpcode() == TargetInstrInfo::INLINEASM) {
const MachineOperand &MO = getOperand(UseOpIdx);
if (!MO.isReg() || !MO.isUse())
return false;
assert(UseOpIdx > 0);
const MachineOperand &UFMO = getOperand(UseOpIdx-1);
if (!UFMO.isImm())
return false; // Must be physreg uses.
unsigned DefNo;
if (InlineAsm::isUseOperandTiedToDef(UFMO.getImm(), DefNo)) {
if (!DefOpIdx)
return true;
unsigned DefIdx = 1;
// Remember to adjust the index. First operand is asm string, then there
// is a flag for each.
while (DefNo) {
const MachineOperand &FMO = getOperand(DefIdx);
assert(FMO.isImm());
// Skip over this def.
DefIdx += InlineAsm::getNumOperandRegisters(FMO.getImm()) + 1;
--DefNo;
}
*DefOpIdx = DefIdx+1;
return true;
}
return false;
}
const TargetInstrDesc &TID = getDesc();
if (UseOpIdx >= TID.getNumOperands())
return false;

50
lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
View File

@ -4932,28 +4932,17 @@ GetRegistersForValue(SDISelAsmOperandInfo &OpInfo,
std::vector<unsigned> RegClassRegs;
const TargetRegisterClass *RC = PhysReg.second;
if (RC) {
// If this is a tied register, our regalloc doesn't know how to maintain
// the constraint, so we have to pick a register to pin the input/output to.
// If it isn't a matched constraint, go ahead and create vreg and let the
// regalloc do its thing.
if (!OpInfo.hasMatchingInput()) {
RegVT = *PhysReg.second->vt_begin();
if (OpInfo.ConstraintVT == MVT::Other)
ValueVT = RegVT;
RegVT = *PhysReg.second->vt_begin();
if (OpInfo.ConstraintVT == MVT::Other)
ValueVT = RegVT;
// Create the appropriate number of virtual registers.
MachineRegisterInfo &RegInfo = MF.getRegInfo();
for (; NumRegs; --NumRegs)
Regs.push_back(RegInfo.createVirtualRegister(PhysReg.second));
OpInfo.AssignedRegs = RegsForValue(TLI, Regs, RegVT, ValueVT);
return;
}
// Otherwise, we can't allocate it. Let the code below figure out how to
// maintain these constraints.
RegClassRegs.assign(PhysReg.second->begin(), PhysReg.second->end());
// Create the appropriate number of virtual registers.
MachineRegisterInfo &RegInfo = MF.getRegInfo();
for (; NumRegs; --NumRegs)
Regs.push_back(RegInfo.createVirtualRegister(PhysReg.second));
OpInfo.AssignedRegs = RegsForValue(TLI, Regs, RegVT, ValueVT);
return;
} else {
// This is a reference to a register class that doesn't directly correspond
// to an LLVM register class. Allocate NumRegs consecutive, available,
@ -5237,8 +5226,8 @@ void SelectionDAGLowering::visitInlineAsm(CallSite CS) {
OpInfo.AssignedRegs.AddInlineAsmOperands(OpInfo.isEarlyClobber ?
6 /* EARLYCLOBBER REGDEF */ :
2 /* REGDEF */ ,
OpInfo.hasMatchingInput(),
OpInfo.MatchingInput,
false,
0,
DAG, AsmNodeOperands);
break;
}
@ -5272,18 +5261,19 @@ void SelectionDAGLowering::visitInlineAsm(CallSite CS) {
RegsForValue MatchedRegs;
MatchedRegs.TLI = &TLI;
MatchedRegs.ValueVTs.push_back(InOperandVal.getValueType());
MatchedRegs.RegVTs.push_back(AsmNodeOperands[CurOp+1].getValueType());
MVT RegVT = AsmNodeOperands[CurOp+1].getValueType();
MatchedRegs.RegVTs.push_back(RegVT);
MachineRegisterInfo &RegInfo = DAG.getMachineFunction().getRegInfo();
for (unsigned i = 0, e = InlineAsm::getNumOperandRegisters(OpFlag);
i != e; ++i) {
unsigned Reg =
cast<RegisterSDNode>(AsmNodeOperands[++CurOp])->getReg();
MatchedRegs.Regs.push_back(Reg);
}
i != e; ++i)
MatchedRegs.Regs.
push_back(RegInfo.createVirtualRegister(TLI.getRegClassFor(RegVT)));
// Use the produced MatchedRegs object to
MatchedRegs.getCopyToRegs(InOperandVal, DAG, getCurDebugLoc(),
Chain, &Flag);
MatchedRegs.AddInlineAsmOperands(1 /*REGUSE*/, false, 0,
MatchedRegs.AddInlineAsmOperands(1 /*REGUSE*/,
true, OpInfo.getMatchedOperand(),
DAG, AsmNodeOperands);
break;
} else {
@ -5291,6 +5281,8 @@ void SelectionDAGLowering::visitInlineAsm(CallSite CS) {
assert((InlineAsm::getNumOperandRegisters(OpFlag)) == 1 &&
"Unexpected number of operands");
// Add information to the INLINEASM node to know about this input.
// See InlineAsm.h isUseOperandTiedToDef.
OpFlag |= 0x80000000 | (OpInfo.getMatchedOperand() << 16);
AsmNodeOperands.push_back(DAG.getTargetConstant(OpFlag,
TLI.getPointerTy()));
AsmNodeOperands.push_back(AsmNodeOperands[CurOp+1]);

9
lib/CodeGen/TwoAddressInstructionPass.cpp
View File

@ -634,7 +634,9 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
ProcessCopy(&*mi, &*mbbi, Processed);
for (unsigned si = 1, e = TID.getNumOperands(); si < e; ++si) {
unsigned NumOps = (mi->getOpcode() == TargetInstrInfo::INLINEASM)
? mi->getNumOperands() : TID.getNumOperands();
for (unsigned si = 0; si < NumOps; ++si) {
unsigned ti = 0;
if (!mi->isRegTiedToDefOperand(si, &ti))
continue;
@ -660,8 +662,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
unsigned regA = mi->getOperand(ti).getReg();
unsigned regB = mi->getOperand(si).getReg();
assert(TargetRegisterInfo::isVirtualRegister(regA) &&
TargetRegisterInfo::isVirtualRegister(regB) &&
assert(TargetRegisterInfo::isVirtualRegister(regB) &&
"cannot update physical register live information");
#ifndef NDEBUG
@ -753,7 +754,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
}
InstructionRearranged:
const TargetRegisterClass* rc = MRI->getRegClass(regA);
const TargetRegisterClass* rc = MRI->getRegClass(regB);
MachineInstr *DefMI = MRI->getVRegDef(regB);
// If it's safe and profitable, remat the definition instead of
// copying it.

32
lib/Target/X86/X86FloatingPoint.cpp
View File

@ -1017,9 +1017,37 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
case X86::MOV_Fp8032:
case X86::MOV_Fp8064:
case X86::MOV_Fp8080: {
unsigned SrcReg = getFPReg(MI->getOperand(1));
unsigned DestReg = getFPReg(MI->getOperand(0));
const MachineOperand &MO1 = MI->getOperand(1);
unsigned SrcReg = getFPReg(MO1);
const MachineOperand &MO0 = MI->getOperand(0);
// These can be created due to inline asm. Two address pass can introduce
// copies from RFP registers to virtual registers.
if (MO0.getReg() == X86::ST0 && SrcReg == 0) {
assert(MO1.isKill());
// Treat %ST0<def> = MOV_Fp8080 %FP0<kill>
// like FpSET_ST0_80 %FP0<kill>, %ST0<imp-def>
assert((StackTop == 1 || StackTop == 2)
&& "Stack should have one or two element on it to return!");
--StackTop; // "Forget" we have something on the top of stack!
break;
} else if (MO0.getReg() == X86::ST1 && SrcReg == 1) {
assert(MO1.isKill());
// Treat %ST1<def> = MOV_Fp8080 %FP1<kill>
// like FpSET_ST1_80 %FP0<kill>, %ST1<imp-def>
// StackTop can be 1 if a FpSET_ST0_* was before this. Exchange them.
if (StackTop == 1) {
BuildMI(*MBB, I, dl, TII->get(X86::XCH_F)).addReg(X86::ST1);
NumFXCH++;
StackTop = 0;
break;
}
assert(StackTop == 2 && "Stack should have two element on it to return!");
--StackTop; // "Forget" we have something on the top of stack!
break;
}
unsigned DestReg = getFPReg(MO0);
if (MI->killsRegister(X86::FP0+SrcReg)) {
// If the input operand is killed, we can just change the owner of the
// incoming stack slot into the result.

4
test/CodeGen/X86/2008-02-20-InlineAsmClobber.ll
View File

@ -1,5 +1,5 @@
; RUN: llvm-as < %s | llc | grep {a: %ecx %ecx}
; RUN: llvm-as < %s | llc | grep {b: %ecx %edx %ecx}
; RUN: llvm-as < %s | llc | grep {a:} | not grep ax
; RUN: llvm-as < %s | llc | grep {b:} | not grep ax
; PR2078
; The clobber list says that "ax" is clobbered. Make sure that eax isn't
; allocated to the input/output register.

4
test/CodeGen/X86/2008-09-18-inline-asm-2.ll
View File

@ -1,5 +1,5 @@
; RUN: llvm-as < %s | llc -march=x86 | grep "#%ebp %eax %edx 8(%esi) %ebx (%edi)"
; RUN: llvm-as < %s | llc -march=x86 -regalloc=local | grep "#%ecx %eax %edx 8(%edi) %ebx (%esi)"
; RUN: llvm-as < %s | llc -march=x86 | grep "#%ebp %edi %esi 8(%edx) %eax (%ebx)"
; RUN: llvm-as < %s | llc -march=x86 -regalloc=local | grep "#%edi %edx %ebp 8(%ebx) %eax (%esi)"
; The 1st, 2nd, 3rd and 5th registers above must all be different. The registers
; referenced in the 4th and 6th operands must not be the same as the 1st or 5th
; operand. There are many combinations that work; this is what llc puts out now.

3
test/CodeGen/X86/2008-12-19-EarlyClobberBug.ll
View File

@ -1,5 +1,6 @@
; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin | %prcontext End 1 | grep {movl.*%ecx}
; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin | %prcontext End 2 | grep mov
; PR3149
; Make sure the copy after inline asm is not coalesced away.
@"\01LC" = internal constant [7 x i8] c"n0=%d\0A\00" ; <[7 x i8]*> [#uses=1]
@llvm.used = appending global [1 x i8*] [ i8* bitcast (i32 (i64, i64)* @umoddi3 to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]

9
test/CodeGen/X86/inline-asm-2addr.ll Normal file
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@ -0,0 +1,9 @@
; RUN: llvm-as < %s | llc -march=x86-64 | grep movq | count 1
define i64 @t(i64 %a, i64 %b) nounwind ssp {
entry:
%asmtmp = tail call i64 asm "rorq $1,$0", "=r,J,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i64 %a) nounwind ; <i64> [#uses=1]
%asmtmp1 = tail call i64 asm "rorq $1,$0", "=r,J,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i64 %b) nounwind ; <i64> [#uses=1]
%0 = add i64 %asmtmp1, %asmtmp ; <i64> [#uses=1]
ret i64 %0
}