Patch to avoid non-pairable NEG instructions

[Jan Hubicka]

Hi,
This patch avoids outputing of NEG instructions that are not pariable
on Pentium.
Also the HI mode pattern is extended to avoid prefixes when possible.

Honza

Mon Apr 12 16:10:18 MET DST 1999
	* i386.md (one_cmplsi2): output pairable XOR instead of NEG on Pentium.
	(one_cmplqi2) Likewise.
	(one_cmplhi2) Likewise; avoid outputing of prefixed opcodes.

*** i386.md.old	Mon Apr 12 15:09:18 1999
--- i386.md	Mon Apr 12 16:34:42 1999
*************** byte_xor_operation:
*** 4832,4850 ****
    [(set (match_operand:SI 0 "nonimmediate_operand" "=rm")
  	(not:SI (match_operand:SI 1 "nonimmediate_operand" "0")))]
    ""
!   "not%L0 %0")
  
  (define_insn "one_cmplhi2"
    [(set (match_operand:HI 0 "nonimmediate_operand" "=rm")
  	(not:HI (match_operand:HI 1 "nonimmediate_operand" "0")))]
    ""
!   "not%W0 %0")
  
  (define_insn "one_cmplqi2"
    [(set (match_operand:QI 0 "nonimmediate_operand" "=qm")
  	(not:QI (match_operand:QI 1 "nonimmediate_operand" "0")))]
    ""
!   "not%B0 %0")
  
  ;;- arithmetic shift instructions
  
--- 4832,4888 ----
    [(set (match_operand:SI 0 "nonimmediate_operand" "=rm")
  	(not:SI (match_operand:SI 1 "nonimmediate_operand" "0")))]
    ""
!   "*
!     rtx xops[2];
!     if (TARGET_PENTIUM && !optimize_size && REG_P (operands[0]))
!       {
! 	xops[0] = operands[0];
! 	xops[1] = GEN_INT (0xffffffff);
! 	output_asm_insn(AS2 (xor%L0,%1,%0), xops);
! 	RET;
!       }
!     return AS1 (not%L0,%0);")
  
  (define_insn "one_cmplhi2"
    [(set (match_operand:HI 0 "nonimmediate_operand" "=rm")
  	(not:HI (match_operand:HI 1 "nonimmediate_operand" "0")))]
    ""
!   "*
!     rtx xops[2];
!     if (TARGET_PENTIUM && !optimize_size && REG_P (operands[0]))
!       {
! 	xops[0] = operands[0];
! 	xops[1] = GEN_INT (0xffff);
! 	if (i386_cc_probably_useless_p (insn))
! 	 {
! 	    CC_STATUS_INIT;
! 	    output_asm_insn(AS2 (xor%L0,%1,%0), xops);
! 	  }
! 	else
! 	  output_asm_insn(AS2 (xor%W0,%1,%0), xops);
! 	RET;
!       }
!     if (REG_P (operands[0]) && i386_cc_probably_useless_p (insn))
!       {
! 	CC_STATUS_INIT;
! 	return AS1 (not%L0,%0);
!       }
!     return AS1 (not%W0,%0);")
  
  (define_insn "one_cmplqi2"
    [(set (match_operand:QI 0 "nonimmediate_operand" "=qm")
  	(not:QI (match_operand:QI 1 "nonimmediate_operand" "0")))]
    ""
!   "*
!     rtx xops[2];
!     if (TARGET_PENTIUM && !optimize_size && REG_P (operands[0]))
!       {
! 	xops[0] = operands[1];
! 	xops[1] = GEN_INT (0xff);
! 	output_asm_insn(AS2 (xor%B0,%1,%0), xops);
! 	RET;
!       }
!     return AS1 (not%B0,%0);")
  
  ;;- arithmetic shift instructions