lib/Target/X86/X86InstrExtension.td

//===- X86InstrExtension.td - Sign and Zero Extensions -----*- tablegen -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file describes the sign and zero extension operations.
//
//===----------------------------------------------------------------------===//

let neverHasSideEffects = 1 in {
  let Defs = [AX], Uses = [AL] in
  def CBW : I<0x98, RawFrm, (outs), (ins),
              "{cbtw|cbw}", []>, OpSize;   // AX = signext(AL)
  let Defs = [EAX], Uses = [AX] in
  def CWDE : I<0x98, RawFrm, (outs), (ins),
              "{cwtl|cwde}", []>;   // EAX = signext(AX)

  let Defs = [AX,DX], Uses = [AX] in
  def CWD : I<0x99, RawFrm, (outs), (ins),
              "{cwtd|cwd}", []>, OpSize; // DX:AX = signext(AX)
  let Defs = [EAX,EDX], Uses = [EAX] in
  def CDQ : I<0x99, RawFrm, (outs), (ins),
              "{cltd|cdq}", []>; // EDX:EAX = signext(EAX)


  let Defs = [RAX], Uses = [EAX] in
  def CDQE : RI<0x98, RawFrm, (outs), (ins),
               "{cltq|cdqe}", []>;     // RAX = signext(EAX)

  let Defs = [RAX,RDX], Uses = [RAX] in
  def CQO  : RI<0x99, RawFrm, (outs), (ins),
                "{cqto|cqo}", []>; // RDX:RAX = signext(RAX)
}


// Sign/Zero extenders
// Use movsbl intead of movsbw; we don't care about the high 16 bits
// of the register here. This has a smaller encoding and avoids a
// partial-register update.  Actual movsbw included for the disassembler.
def MOVSX16rr8W : I<0xBE, MRMSrcReg, (outs GR16:$dst), (ins GR8:$src),
                    "movs{bw|x}\t{$src, $dst|$dst, $src}", []>, TB, OpSize;
def MOVSX16rm8W : I<0xBE, MRMSrcMem, (outs GR16:$dst), (ins i8mem:$src),
                    "movs{bw|x}\t{$src, $dst|$dst, $src}", []>, TB, OpSize;
def MOVSX16rr8 : I<0xBE, MRMSrcReg, (outs GR16:$dst), (ins GR8 :$src),
                   "movs{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR16:$dst, (sext GR8:$src))]>, TB;
def MOVSX16rm8 : I<0xBE, MRMSrcMem, (outs GR16:$dst), (ins i8mem :$src),
                   "movs{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR16:$dst, (sextloadi16i8 addr:$src))]>, TB;
def MOVSX32rr8 : I<0xBE, MRMSrcReg, (outs GR32:$dst), (ins GR8 :$src),
                   "movs{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (sext GR8:$src))]>, TB;
def MOVSX32rm8 : I<0xBE, MRMSrcMem, (outs GR32:$dst), (ins i8mem :$src),
                   "movs{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (sextloadi32i8 addr:$src))]>, TB;
def MOVSX32rr16: I<0xBF, MRMSrcReg, (outs GR32:$dst), (ins GR16:$src),
                   "movs{wl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (sext GR16:$src))]>, TB;
def MOVSX32rm16: I<0xBF, MRMSrcMem, (outs GR32:$dst), (ins i16mem:$src),
                   "movs{wl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (sextloadi32i16 addr:$src))]>, TB;

// Use movzbl intead of movzbw; we don't care about the high 16 bits
// of the register here. This has a smaller encoding and avoids a
// partial-register update.  Actual movzbw included for the disassembler.
def MOVZX16rr8W : I<0xB6, MRMSrcReg, (outs GR16:$dst), (ins GR8:$src),
                    "movz{bw|x}\t{$src, $dst|$dst, $src}", []>, TB, OpSize;
def MOVZX16rm8W : I<0xB6, MRMSrcMem, (outs GR16:$dst), (ins i8mem:$src),
                    "movz{bw|x}\t{$src, $dst|$dst, $src}", []>, TB, OpSize;  
def MOVZX16rr8 : I<0xB6, MRMSrcReg, (outs GR16:$dst), (ins GR8 :$src),
                   "movz{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR16:$dst, (zext GR8:$src))]>, TB;
def MOVZX16rm8 : I<0xB6, MRMSrcMem, (outs GR16:$dst), (ins i8mem :$src),
                   "movz{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR16:$dst, (zextloadi16i8 addr:$src))]>, TB;
def MOVZX32rr8 : I<0xB6, MRMSrcReg, (outs GR32:$dst), (ins GR8 :$src),
                   "movz{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (zext GR8:$src))]>, TB;
def MOVZX32rm8 : I<0xB6, MRMSrcMem, (outs GR32:$dst), (ins i8mem :$src),
                   "movz{bl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (zextloadi32i8 addr:$src))]>, TB;
def MOVZX32rr16: I<0xB7, MRMSrcReg, (outs GR32:$dst), (ins GR16:$src),
                   "movz{wl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (zext GR16:$src))]>, TB;
def MOVZX32rm16: I<0xB7, MRMSrcMem, (outs GR32:$dst), (ins i16mem:$src),
                   "movz{wl|x}\t{$src, $dst|$dst, $src}",
                   [(set GR32:$dst, (zextloadi32i16 addr:$src))]>, TB;

// These are the same as the regular MOVZX32rr8 and MOVZX32rm8
// except that they use GR32_NOREX for the output operand register class
// instead of GR32. This allows them to operate on h registers on x86-64.
def MOVZX32_NOREXrr8 : I<0xB6, MRMSrcReg,
                         (outs GR32_NOREX:$dst), (ins GR8:$src),
                         "movz{bl|x}\t{$src, $dst|$dst, $src}",
                         []>, TB;
let mayLoad = 1 in
def MOVZX32_NOREXrm8 : I<0xB6, MRMSrcMem,
                         (outs GR32_NOREX:$dst), (ins i8mem:$src),
                         "movz{bl|x}\t{$src, $dst|$dst, $src}",
                         []>, TB;

// MOVSX64rr8 always has a REX prefix and it has an 8-bit register
// operand, which makes it a rare instruction with an 8-bit register
// operand that can never access an h register. If support for h registers
// were generalized, this would require a special register class.
def MOVSX64rr8 : RI<0xBE, MRMSrcReg, (outs GR64:$dst), (ins GR8 :$src),
                    "movs{bq|x}\t{$src, $dst|$dst, $src}",
                    [(set GR64:$dst, (sext GR8:$src))]>, TB;
def MOVSX64rm8 : RI<0xBE, MRMSrcMem, (outs GR64:$dst), (ins i8mem :$src),
                    "movs{bq|x}\t{$src, $dst|$dst, $src}",
                    [(set GR64:$dst, (sextloadi64i8 addr:$src))]>, TB;
def MOVSX64rr16: RI<0xBF, MRMSrcReg, (outs GR64:$dst), (ins GR16:$src),
                    "movs{wq|x}\t{$src, $dst|$dst, $src}",
                    [(set GR64:$dst, (sext GR16:$src))]>, TB;
def MOVSX64rm16: RI<0xBF, MRMSrcMem, (outs GR64:$dst), (ins i16mem:$src),
                    "movs{wq|x}\t{$src, $dst|$dst, $src}",
                    [(set GR64:$dst, (sextloadi64i16 addr:$src))]>, TB;
def MOVSX64rr32: RI<0x63, MRMSrcReg, (outs GR64:$dst), (ins GR32:$src),
                    "movs{lq|xd}\t{$src, $dst|$dst, $src}",
                    [(set GR64:$dst, (sext GR32:$src))]>;
def MOVSX64rm32: RI<0x63, MRMSrcMem, (outs GR64:$dst), (ins i32mem:$src),
                    "movs{lq|xd}\t{$src, $dst|$dst, $src}",
                    [(set GR64:$dst, (sextloadi64i32 addr:$src))]>;

// movzbq and movzwq encodings for the disassembler
def MOVZX64rr8_Q : RI<0xB6, MRMSrcReg, (outs GR64:$dst), (ins GR8:$src),
                       "movz{bq|x}\t{$src, $dst|$dst, $src}", []>, TB;
def MOVZX64rm8_Q : RI<0xB6, MRMSrcMem, (outs GR64:$dst), (ins i8mem:$src),
                       "movz{bq|x}\t{$src, $dst|$dst, $src}", []>, TB;
def MOVZX64rr16_Q : RI<0xB7, MRMSrcReg, (outs GR64:$dst), (ins GR16:$src),
                       "movz{wq|x}\t{$src, $dst|$dst, $src}", []>, TB;
def MOVZX64rm16_Q : RI<0xB7, MRMSrcMem, (outs GR64:$dst), (ins i16mem:$src),
                       "movz{wq|x}\t{$src, $dst|$dst, $src}", []>, TB;

// FIXME: These should be Pat patterns.
let isCodeGenOnly = 1 in {

// Use movzbl instead of movzbq when the destination is a register; it's
// equivalent due to implicit zero-extending, and it has a smaller encoding.
def MOVZX64rr8 : I<0xB6, MRMSrcReg, (outs GR64:$dst), (ins GR8 :$src),
                   "", [(set GR64:$dst, (zext GR8:$src))]>, TB;
def MOVZX64rm8 : I<0xB6, MRMSrcMem, (outs GR64:$dst), (ins i8mem :$src),
                   "", [(set GR64:$dst, (zextloadi64i8 addr:$src))]>, TB;
// Use movzwl instead of movzwq when the destination is a register; it's
// equivalent due to implicit zero-extending, and it has a smaller encoding.
def MOVZX64rr16: I<0xB7, MRMSrcReg, (outs GR64:$dst), (ins GR16:$src),
                   "", [(set GR64:$dst, (zext GR16:$src))]>, TB;
def MOVZX64rm16: I<0xB7, MRMSrcMem, (outs GR64:$dst), (ins i16mem:$src),
                   "", [(set GR64:$dst, (zextloadi64i16 addr:$src))]>, TB;

// There's no movzlq instruction, but movl can be used for this purpose, using
// implicit zero-extension. The preferred way to do 32-bit-to-64-bit zero
// extension on x86-64 is to use a SUBREG_TO_REG to utilize implicit
// zero-extension, however this isn't possible when the 32-bit value is
// defined by a truncate or is copied from something where the high bits aren't
// necessarily all zero. In such cases, we fall back to these explicit zext
// instructions.
def MOVZX64rr32 : I<0x89, MRMDestReg, (outs GR64:$dst), (ins GR32:$src),
                    "", [(set GR64:$dst, (zext GR32:$src))]>;
def MOVZX64rm32 : I<0x8B, MRMSrcMem, (outs GR64:$dst), (ins i32mem:$src),
                    "", [(set GR64:$dst, (zextloadi64i32 addr:$src))]>;


}