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Annotate X86InstrCompiler.td with SchedRW lists. 

Add a new WriteZero SchedWrite type for the common dependency-breaking
instructions that clear a register.

llvm-svn: 177442
This commit is contained in:
Jakob Stoklund Olesen 2013-03-19 21:16:56 +00:00
parent 993bd120bc
commit 9bd6b8bd96
2 changed files with 13 additions and 8 deletions
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17
llvm/lib/Target/X86/X86InstrCompiler.td
View File

@ -153,7 +153,7 @@ let isTerminator = 1, isReturn = 1, isBarrier = 1,
hasCtrlDep = 1, isCodeGenOnly = 1 in {
def EH_RETURN : I<0xC3, RawFrm, (outs), (ins GR32:$addr),
"ret\t#eh_return, addr: $addr",
[(X86ehret GR32:$addr)], IIC_RET>;
[(X86ehret GR32:$addr)], IIC_RET>, Sched<[WriteJumpLd]>;
}
@ -161,7 +161,7 @@ let isTerminator = 1, isReturn = 1, isBarrier = 1,
hasCtrlDep = 1, isCodeGenOnly = 1 in {
def EH_RETURN64 : I<0xC3, RawFrm, (outs), (ins GR64:$addr),
"ret\t#eh_return, addr: $addr",
[(X86ehret GR64:$addr)], IIC_RET>;
[(X86ehret GR64:$addr)], IIC_RET>, Sched<[WriteJumpLd]>;
}
@ -220,7 +220,7 @@ def MORESTACK_RET_RESTORE_R10 : I<0, Pseudo, (outs), (ins),
let Defs = [EFLAGS], isReMaterializable = 1, isAsCheapAsAMove = 1,
isCodeGenOnly = 1 in {
def MOV8r0 : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins), "",
[(set GR8:$dst, 0)], IIC_ALU_NONMEM>;
[(set GR8:$dst, 0)], IIC_ALU_NONMEM>, Sched<[WriteZero]>;
// We want to rewrite MOV16r0 in terms of MOV32r0, because it's a smaller
// encoding and avoids a partial-register update sometimes, but doing so
@ -229,11 +229,12 @@ def MOV8r0 : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins), "",
// to an MCInst.
def MOV16r0 : I<0x31, MRMInitReg, (outs GR16:$dst), (ins),
"",
[(set GR16:$dst, 0)], IIC_ALU_NONMEM>, OpSize;
[(set GR16:$dst, 0)], IIC_ALU_NONMEM>, OpSize,
Sched<[WriteZero]>;
// FIXME: Set encoding to pseudo.
def MOV32r0 : I<0x31, MRMInitReg, (outs GR32:$dst), (ins), "",
[(set GR32:$dst, 0)], IIC_ALU_NONMEM>;
[(set GR32:$dst, 0)], IIC_ALU_NONMEM>, Sched<[WriteZero]>;
}
// We want to rewrite MOV64r0 in terms of MOV32r0, because it's sometimes a
@ -245,7 +246,7 @@ def MOV32r0 : I<0x31, MRMInitReg, (outs GR32:$dst), (ins), "",
let Defs = [EFLAGS], isCodeGenOnly=1,
AddedComplexity = 1, isReMaterializable = 1, isAsCheapAsAMove = 1 in
def MOV64r0 : I<0x31, MRMInitReg, (outs GR64:$dst), (ins), "",
[(set GR64:$dst, 0)], IIC_ALU_NONMEM>;
[(set GR64:$dst, 0)], IIC_ALU_NONMEM>, Sched<[WriteZero]>;
// Materialize i64 constant where top 32-bits are zero. This could theoretically
// use MOV32ri with a SUBREG_TO_REG to represent the zero-extension, however
@ -254,10 +255,10 @@ let AddedComplexity = 1, isReMaterializable = 1, isAsCheapAsAMove = 1,
isCodeGenOnly = 1 in
def MOV64ri64i32 : Ii32<0xB8, AddRegFrm, (outs GR64:$dst), (ins i64i32imm:$src),
"", [(set GR64:$dst, i64immZExt32:$src)],
IIC_ALU_NONMEM>;
IIC_ALU_NONMEM>, Sched<[WriteALU]>;
// Use sbb to materialize carry bit.
let Uses = [EFLAGS], Defs = [EFLAGS], isPseudo = 1 in {
let Uses = [EFLAGS], Defs = [EFLAGS], isPseudo = 1, SchedRW = [WriteALU] in {
// FIXME: These are pseudo ops that should be replaced with Pat<> patterns.
// However, Pat<> can't replicate the destination reg into the inputs of the
// result.

4
llvm/lib/Target/X86/X86Schedule.td
View File

@ -53,6 +53,10 @@ def WriteLoad : SchedWrite;
def WriteStore : SchedWrite;
def WriteMove : SchedWrite;
// Idioms that clear a register, like xorps %xmm0, %xmm0.
// These can often bypass execution ports completely.
def WriteZero : SchedWrite;
// Branches don't produce values, so they have no latency, but they still
// consume resources. Indirect branches can fold loads.
defm WriteJump : X86SchedWritePair;