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Fix Mul/Div clobbers

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llvm-svn: 4718
This commit is contained in:
Chris Lattner 2002-11-17 21:56:38 +00:00
parent 16b1ec97f0
commit 72e99c8344
1 changed files with 23 additions and 12 deletions
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35
lib/Target/X86/InstSelectSimple.cpp
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@ -19,6 +19,8 @@
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Support/InstVisitor.h"
using namespace MOTy; // Get Use, Def, UseAndDef
namespace {
struct ISel : public FunctionPass, InstVisitor<ISel> {
TargetMachine &TM;
@ -147,6 +149,7 @@ static inline TypeClass getClass(const Type *Ty) {
}
}
/// copyConstantToRegister - Output the instructions required to put the
/// specified constant into the specified register.
///
@ -173,6 +176,7 @@ void ISel::copyConstantToRegister(Constant *C, unsigned R) {
}
}
/// SetCC instructions - Here we just emit boilerplate code to set a byte-sized
/// register, then move it to wherever the result should be.
/// We handle FP setcc instructions by pushing them, doing a
@ -327,8 +331,8 @@ ISel::visitSetCondInst (SetCondInst & I)
/// ret short, ushort: Extend value into EAX and return
/// ret int, uint : Move value into EAX and return
/// ret pointer : Move value into EAX and return
/// ret long, ulong : Move value into EAX/EDX (?) and return
/// ret float/double : ? Top of FP stack? XMM0?
/// ret long, ulong : Move value into EAX/EDX and return
/// ret float/double : Top of FP stack
///
void ISel::visitReturnInst (ReturnInst &I) {
if (I.getNumOperands() == 0) {
@ -382,6 +386,7 @@ void ISel::visitReturnInst (ReturnInst &I) {
BuildMI(BB, X86::RET, 0);
}
/// visitBranchInst - Handle conditional and unconditional branches here. Note
/// that since code layout is frozen at this point, that if we are trying to
/// jump to a block that is the immediate successor of the current block, we can
@ -433,24 +438,27 @@ void ISel::visitMul(BinaryOperator &I) {
visitInstruction(I);
static const unsigned Regs[] ={ X86::AL , X86::AX , X86::EAX };
static const unsigned Clobbers[] ={ X86::AH , X86::DX , X86::EDX };
static const unsigned MulOpcode[]={ X86::MULrr8, X86::MULrr16, X86::MULrr32 };
static const unsigned MovOpcode[]={ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32 };
unsigned Reg = Regs[Class];
unsigned Op0Reg = getReg(I.getOperand(0));
unsigned Op1Reg = getReg(I.getOperand(1));
unsigned Reg = Regs[Class];
unsigned Clobber = Clobbers[Class];
unsigned Op0Reg = getReg(I.getOperand(0));
unsigned Op1Reg = getReg(I.getOperand(1));
// Put the first operand into one of the A registers...
BuildMI(BB, MovOpcode[Class], 1, Reg).addReg(Op0Reg);
// Emit the appropriate multiple instruction...
// FIXME: We need to mark that this modified AH, DX, or EDX also!!
BuildMI(BB, MulOpcode[Class], 2, Reg).addReg(Reg).addReg(Op1Reg);
// Emit the appropriate multiply instruction...
BuildMI(BB, MulOpcode[Class], 4)
.addReg(Reg, UseAndDef).addReg(Op1Reg).addClobber(Clobber);
// Put the result into the destination register...
BuildMI(BB, MovOpcode[Class], 1, getReg(I)).addReg(Reg);
}
/// visitDivRem - Handle division and remainder instructions... these
/// instruction both require the same instructions to be generated, they just
/// select the result from a different register. Note that both of these
@ -489,17 +497,18 @@ void ISel::visitDivRem(BinaryOperator &I) {
BuildMI(BB, ClrOpcode[Class], 2, ExtReg).addReg(ExtReg).addReg(ExtReg);
}
// Emit the appropriate divide or remainder instruction...
BuildMI(BB, DivOpcode[isSigned][Class], 2)
.addReg(Reg, UseAndDef).addReg(ExtReg, UseAndDef).addReg(Op1Reg);
// Figure out which register we want to pick the result out of...
unsigned DestReg = (I.getOpcode() == Instruction::Div) ? Reg : ExtReg;
// Emit the appropriate divide or remainder instruction...
// FIXME: We need to mark that this modified AH, DX, or EDX also!!
BuildMI(BB,DivOpcode[isSigned][Class], 2, DestReg).addReg(Reg).addReg(Op1Reg);
// Put the result into the destination register...
BuildMI(BB, MovOpcode[Class], 1, getReg(I)).addReg(DestReg);
}
/// Shift instructions: 'shl', 'sar', 'shr' - Some special cases here
/// for constant immediate shift values, and for constant immediate
/// shift values equal to 1. Even the general case is sort of special,
@ -561,6 +570,7 @@ void ISel::visitShiftInst (ShiftInst &I) {
}
}
/// visitLoadInst - Implement LLVM load instructions in terms of the x86 'mov'
/// instruction.
///
@ -575,6 +585,7 @@ void ISel::visitLoadInst(LoadInst &I) {
addDirectMem(BuildMI(BB, Opcode[Class], 4, getReg(I)), AddressReg);
}
/// visitStoreInst - Implement LLVM store instructions in terms of the x86 'mov'
/// instruction.
///