Add "mayHaveSideEffects" and "neverHasSideEffects" flags to some instructions. I

based what flag to set on whether it was already marked as
"isRematerializable". If there was a further check to determine if it's "really"
rematerializable, then I marked it as "mayHaveSideEffects" and created a check
in the X86 back-end similar to the remat one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45132 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2007-12-17 23:07:56 +00:00
parent f9b83fcf95
commit 627c00b663
7 changed files with 57 additions and 21 deletions

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@ -349,7 +349,7 @@ def CMOVNP_F : FPI<0xD8, AddRegFrm, (outs RST:$op), (ins),
let isLoad = 1 in {
def LD_Fp32m : FpIf32<(outs RFP32:$dst), (ins f32mem:$src), ZeroArgFP,
[(set RFP32:$dst, (loadf32 addr:$src))]>;
let isReMaterializable = 1 in
let isReMaterializable = 1, mayHaveSideEffects = 1 in
def LD_Fp64m : FpIf64<(outs RFP64:$dst), (ins f64mem:$src), ZeroArgFP,
[(set RFP64:$dst, (loadf64 addr:$src))]>;
def LD_Fp80m : FpI_<(outs RFP80:$dst), (ins f80mem:$src), ZeroArgFP,
@ -466,7 +466,7 @@ def ST_FPrr : FPI<0xD8, AddRegFrm, (outs), (ins RST:$op), "fstp\t$op">, DD;
def XCH_F : FPI<0xC8, AddRegFrm, (outs), (ins RST:$op), "fxch\t$op">, D9;
// Floating point constant loads.
let isReMaterializable = 1 in {
let isReMaterializable = 1, neverHasSideEffects = 1 in {
def LD_Fp032 : FpIf32<(outs RFP32:$dst), (ins), ZeroArgFP,
[(set RFP32:$dst, fpimm0)]>;
def LD_Fp132 : FpIf32<(outs RFP32:$dst), (ins), ZeroArgFP,

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@ -144,6 +144,40 @@ bool X86InstrInfo::isReallyTriviallyReMaterializable(MachineInstr *MI) const {
return true;
}
/// isReallySideEffectFree - If the M_MAY_HAVE_SIDE_EFFECTS flag is set, this
/// method is called to determine if the specific instance of this instruction
/// has side effects. This is useful in cases of instructions, like loads, which
/// generally always have side effects. A load from a constant pool doesn't have
/// side effects, though. So we need to differentiate it from the general case.
bool X86InstrInfo::isReallySideEffectFree(MachineInstr *MI) const {
switch (MI->getOpcode()) {
default: break;
case X86::MOV8rm:
case X86::MOV16rm:
case X86::MOV16_rm:
case X86::MOV32rm:
case X86::MOV32_rm:
case X86::MOV64rm:
case X86::LD_Fp64m:
case X86::MOVSSrm:
case X86::MOVSDrm:
case X86::MOVAPSrm:
case X86::MOVAPDrm:
case X86::MMX_MOVD64rm:
case X86::MMX_MOVQ64rm:
// Loads from constant pools have no side effects
return MI->getOperand(1).isRegister() && MI->getOperand(2).isImmediate() &&
MI->getOperand(3).isRegister() && MI->getOperand(4).isConstantPoolIndex() &&
MI->getOperand(1).getReg() == 0 &&
MI->getOperand(2).getImmedValue() == 1 &&
MI->getOperand(3).getReg() == 0;
}
// All other instances of these instructions are presumed to have side
// effects.
return false;
}
/// hasLiveCondCodeDef - True if MI has a condition code def, e.g. EFLAGS, that
/// is not marked dead.
static bool hasLiveCondCodeDef(MachineInstr *MI) {

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@ -240,7 +240,8 @@ public:
unsigned isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const;
unsigned isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const;
bool isReallyTriviallyReMaterializable(MachineInstr *MI) const;
bool isReallySideEffectFree(MachineInstr *MI) const;
/// convertToThreeAddress - This method must be implemented by targets that
/// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
/// may be able to convert a two-address instruction into a true

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@ -563,7 +563,7 @@ def MOV16rr : I<0x89, MRMDestReg, (outs GR16:$dst), (ins GR16:$src),
"mov{w}\t{$src, $dst|$dst, $src}", []>, OpSize;
def MOV32rr : I<0x89, MRMDestReg, (outs GR32:$dst), (ins GR32:$src),
"mov{l}\t{$src, $dst|$dst, $src}", []>;
let isReMaterializable = 1 in {
let isReMaterializable = 1, neverHasSideEffects = 1 in {
def MOV8ri : Ii8 <0xB0, AddRegFrm, (outs GR8 :$dst), (ins i8imm :$src),
"mov{b}\t{$src, $dst|$dst, $src}",
[(set GR8:$dst, imm:$src)]>;
@ -584,7 +584,7 @@ def MOV32mi : Ii32<0xC7, MRM0m, (outs), (ins i32mem:$dst, i32imm:$src),
"mov{l}\t{$src, $dst|$dst, $src}",
[(store (i32 imm:$src), addr:$dst)]>;
let isLoad = 1 in {
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in {
def MOV8rm : I<0x8A, MRMSrcMem, (outs GR8 :$dst), (ins i8mem :$src),
"mov{b}\t{$src, $dst|$dst, $src}",
[(set GR8:$dst, (load addr:$src))]>;
@ -2463,7 +2463,7 @@ def CDQ : I<0x99, RawFrm, (outs), (ins),
// Alias instructions that map movr0 to xor.
// FIXME: remove when we can teach regalloc that xor reg, reg is ok.
let Defs = [EFLAGS], isReMaterializable = 1 in {
let Defs = [EFLAGS], isReMaterializable = 1, neverHasSideEffects = 1 in {
def MOV8r0 : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins),
"xor{b}\t$dst, $dst",
[(set GR8:$dst, 0)]>;
@ -2486,7 +2486,7 @@ def MOV16_rr : I<0x89, MRMDestReg, (outs GR16_:$dst), (ins GR16_:$src),
"mov{w}\t{$src, $dst|$dst, $src}", []>, OpSize;
def MOV32_rr : I<0x89, MRMDestReg, (outs GR32_:$dst), (ins GR32_:$src),
"mov{l}\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1 in {
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in {
def MOV16_rm : I<0x8B, MRMSrcMem, (outs GR16_:$dst), (ins i16mem:$src),
"mov{w}\t{$src, $dst|$dst, $src}", []>, OpSize;
def MOV32_rm : I<0x8B, MRMSrcMem, (outs GR32_:$dst), (ins i32mem:$src),

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@ -158,7 +158,7 @@ def MMX_FEMMS : MMXI<0x0E, RawFrm, (outs), (ins), "femms", [(int_x86_mmx_femms)]
// Data Transfer Instructions
def MMX_MOVD64rr : MMXI<0x6E, MRMSrcReg, (outs VR64:$dst), (ins GR32:$src),
"movd\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1, isReMaterializable = 1 in
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
def MMX_MOVD64rm : MMXI<0x6E, MRMSrcMem, (outs VR64:$dst), (ins i32mem:$src),
"movd\t{$src, $dst|$dst, $src}", []>;
def MMX_MOVD64mr : MMXI<0x7E, MRMDestMem, (outs), (ins i32mem:$dst, VR64:$src),
@ -169,7 +169,7 @@ def MMX_MOVD64to64rr : MMXRI<0x6E, MRMSrcReg, (outs VR64:$dst), (ins GR64:$src),
def MMX_MOVQ64rr : MMXI<0x6F, MRMSrcReg, (outs VR64:$dst), (ins VR64:$src),
"movq\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1, isReMaterializable = 1 in
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
def MMX_MOVQ64rm : MMXI<0x6F, MRMSrcMem, (outs VR64:$dst), (ins i64mem:$src),
"movq\t{$src, $dst|$dst, $src}",
[(set VR64:$dst, (load_mmx addr:$src))]>;
@ -487,7 +487,7 @@ def MMX_MASKMOVQ : MMXI<0xF7, MRMDestMem, (outs), (ins VR64:$src, VR64:$mask),
//===----------------------------------------------------------------------===//
// Alias instructions that map zero vector to pxor.
let isReMaterializable = 1 in {
let isReMaterializable = 1, neverHasSideEffects = 1 in {
def MMX_V_SET0 : MMXI<0xEF, MRMInitReg, (outs VR64:$dst), (ins),
"pxor\t$dst, $dst",
[(set VR64:$dst, (v2i32 immAllZerosV))]>;

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@ -301,7 +301,7 @@ let Uses = [EFLAGS], usesCustomDAGSchedInserter = 1 in {
// Move Instructions
def MOVSSrr : SSI<0x10, MRMSrcReg, (outs FR32:$dst), (ins FR32:$src),
"movss\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1, isReMaterializable = 1 in
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
def MOVSSrm : SSI<0x10, MRMSrcMem, (outs FR32:$dst), (ins f32mem:$src),
"movss\t{$src, $dst|$dst, $src}",
[(set FR32:$dst, (loadf32 addr:$src))]>;
@ -445,7 +445,7 @@ def Int_COMISSrm: PSI<0x2F, MRMSrcMem, (outs),
// start with 'Fs'.
// Alias instructions that map fld0 to pxor for sse.
let isReMaterializable = 1 in
let isReMaterializable = 1, neverHasSideEffects = 1 in
def FsFLD0SS : I<0xEF, MRMInitReg, (outs FR32:$dst), (ins),
"pxor\t$dst, $dst", [(set FR32:$dst, fp32imm0)]>,
Requires<[HasSSE1]>, TB, OpSize;
@ -634,7 +634,7 @@ defm MIN : sse1_fp_binop_rm<0x5D, "min", X86fmin,
// Move Instructions
def MOVAPSrr : PSI<0x28, MRMSrcReg, (outs VR128:$dst), (ins VR128:$src),
"movaps\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1, isReMaterializable = 1 in
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
def MOVAPSrm : PSI<0x28, MRMSrcMem, (outs VR128:$dst), (ins f128mem:$src),
"movaps\t{$src, $dst|$dst, $src}",
[(set VR128:$dst, (alignedloadv4f32 addr:$src))]>;
@ -940,7 +940,7 @@ def STMXCSR : PSI<0xAE, MRM3m, (outs), (ins i32mem:$dst),
"stmxcsr\t$dst", [(int_x86_sse_stmxcsr addr:$dst)]>;
// Alias instructions that map zero vector to pxor / xorp* for sse.
let isReMaterializable = 1 in
let isReMaterializable = 1, neverHasSideEffects = 1 in
def V_SET0 : PSI<0x57, MRMInitReg, (outs VR128:$dst), (ins),
"xorps\t$dst, $dst",
[(set VR128:$dst, (v4i32 immAllZerosV))]>;
@ -1003,7 +1003,7 @@ def MOVZSS2PSrm : SSI<0x10, MRMSrcMem, (outs VR128:$dst), (ins f32mem:$src),
// Move Instructions
def MOVSDrr : SDI<0x10, MRMSrcReg, (outs FR64:$dst), (ins FR64:$src),
"movsd\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1, isReMaterializable = 1 in
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
def MOVSDrm : SDI<0x10, MRMSrcMem, (outs FR64:$dst), (ins f64mem:$src),
"movsd\t{$src, $dst|$dst, $src}",
[(set FR64:$dst, (loadf64 addr:$src))]>;
@ -1141,7 +1141,7 @@ def Int_COMISDrm: PDI<0x2F, MRMSrcMem, (outs), (ins VR128:$src1, f128mem:$src2),
// start with 'Fs'.
// Alias instructions that map fld0 to pxor for sse.
let isReMaterializable = 1 in
let isReMaterializable = 1, neverHasSideEffects = 1 in
def FsFLD0SD : I<0xEF, MRMInitReg, (outs FR64:$dst), (ins),
"pxor\t$dst, $dst", [(set FR64:$dst, fpimm0)]>,
Requires<[HasSSE2]>, TB, OpSize;
@ -1330,7 +1330,7 @@ defm MIN : sse2_fp_binop_rm<0x5D, "min", X86fmin,
// Move Instructions
def MOVAPDrr : PDI<0x28, MRMSrcReg, (outs VR128:$dst), (ins VR128:$src),
"movapd\t{$src, $dst|$dst, $src}", []>;
let isLoad = 1, isReMaterializable = 1 in
let isLoad = 1, isReMaterializable = 1, mayHaveSideEffects = 1 in
def MOVAPDrm : PDI<0x28, MRMSrcMem, (outs VR128:$dst), (ins f128mem:$src),
"movapd\t{$src, $dst|$dst, $src}",
[(set VR128:$dst, (alignedloadv2f64 addr:$src))]>;
@ -2119,7 +2119,7 @@ def MFENCE : I<0xAE, MRM6m, (outs), (ins),
// Alias instructions that map zero vector to pxor / xorp* for sse.
let isReMaterializable = 1 in
let isReMaterializable = 1, neverHasSideEffects = 1 in
def V_SETALLONES : PDI<0x76, MRMInitReg, (outs VR128:$dst), (ins),
"pcmpeqd\t$dst, $dst",
[(set VR128:$dst, (v4i32 immAllOnesV))]>;

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@ -201,7 +201,7 @@ def REP_STOSQ : RI<0xAB, RawFrm, (outs), (ins), "{rep;stosq|rep stosq}",
def MOV64rr : RI<0x89, MRMDestReg, (outs GR64:$dst), (ins GR64:$src),
"mov{q}\t{$src, $dst|$dst, $src}", []>;
let isReMaterializable = 1 in {
let isReMaterializable = 1, neverHasSideEffects = 1 in {
def MOV64ri : RIi64<0xB8, AddRegFrm, (outs GR64:$dst), (ins i64imm:$src),
"movabs{q}\t{$src, $dst|$dst, $src}",
[(set GR64:$dst, imm:$src)]>;
@ -1105,13 +1105,14 @@ def PsMOVZX64rm32: I<0x8B, MRMSrcMem, (outs GR64:$dst), (ins i32mem:$src),
// FIXME: remove when we can teach regalloc that xor reg, reg is ok.
// FIXME: AddedComplexity gives MOV64r0 a higher priority than MOV64ri32. Remove
// when we have a better way to specify isel priority.
let Defs = [EFLAGS], AddedComplexity = 1, isReMaterializable = 1 in
let Defs = [EFLAGS], AddedComplexity = 1, isReMaterializable = 1,
neverHasSideEffects = 1 in
def MOV64r0 : RI<0x31, MRMInitReg, (outs GR64:$dst), (ins),
"xor{l}\t${dst:subreg32}, ${dst:subreg32}",
[(set GR64:$dst, 0)]>;
// Materialize i64 constant where top 32-bits are zero.
let AddedComplexity = 1, isReMaterializable = 1 in
let AddedComplexity = 1, isReMaterializable = 1, neverHasSideEffects = 1 in
def MOV64ri64i32 : Ii32<0xB8, AddRegFrm, (outs GR64:$dst), (ins i64i32imm:$src),
"mov{l}\t{$src, ${dst:subreg32}|${dst:subreg32}, $src}",
[(set GR64:$dst, i64immZExt32:$src)]>;