On Tue, Jan 05, 2010 at 04:03:00PM -0800, Richard Henderson wrote: > This avoids an unnecessary REX.W prefix when dealing with AND > operands that fit into a 32-bit quantity. The most common change > actually seen is movz[wb]q -> movz[wb]l. > > Similarly, avoid REXW in ext{8,16}u_i64 tcg opcodes. > > Signed-off-by: Richard Henderson <r...@twiddle.net> > --- > tcg/x86_64/tcg-target.c | 26 ++++++++------------------ > 1 files changed, 8 insertions(+), 18 deletions(-) > > diff --git a/tcg/x86_64/tcg-target.c b/tcg/x86_64/tcg-target.c > index 2339091..f584c94 100644 > --- a/tcg/x86_64/tcg-target.c > +++ b/tcg/x86_64/tcg-target.c > @@ -426,24 +426,18 @@ static inline void tgen_arithi64(TCGContext *s, int c, > int r0, int64_t val) > } else if ((c == ARITH_ADD && val == -1) || (c == ARITH_SUB && val == > 1)) { > /* dec */ > tcg_out_modrm(s, 0xff | P_REXW, 1, r0); > - } else if (val == (int8_t)val) { > - tcg_out_modrm(s, 0x83 | P_REXW, c, r0); > - tcg_out8(s, val); > - } else if (c == ARITH_AND && val == 0xffu) { > - /* movzbl */ > - tcg_out_modrm(s, 0xb6 | P_EXT | P_REXW, r0, r0); > - } else if (c == ARITH_AND && val == 0xffffu) { > - /* movzwl */ > - tcg_out_modrm(s, 0xb7 | P_EXT | P_REXW, r0, r0); > } else if (c == ARITH_AND && val == 0xffffffffu) { > /* 32-bit mov zero extends */ > tcg_out_modrm(s, 0x8b, r0, r0); > + } else if (c == ARITH_AND && (uint64_t)val <= 0xffffffffu) { > + /* AND with no high bits set can use a 32-bit operation. */ > + tgen_arithi32(s, c, r0, val);
Do we really want to call tgen_arithi32() here, that will redo part of the above tests again? It might be better to simply remove the REX.W prefix above instead. > + } else if (val == (int8_t)val) { > + tcg_out_modrm(s, 0x83 | P_REXW, c, r0); > + tcg_out8(s, val); > } else if (val == (int32_t)val) { > tcg_out_modrm(s, 0x81 | P_REXW, c, r0); > tcg_out32(s, val); > - } else if (c == ARITH_AND && val == (uint32_t)val) { > - tcg_out_modrm(s, 0x81, c, r0); > - tcg_out32(s, val); > } else { > tcg_abort(); > } > @@ -1182,16 +1176,12 @@ static inline void tcg_out_op(TCGContext *s, int opc, > const TCGArg *args, > tcg_out_modrm(s, 0x63 | P_REXW, args[0], args[1]); > break; > case INDEX_op_ext8u_i32: > + case INDEX_op_ext8u_i64: > tcg_out_modrm(s, 0xb6 | P_EXT | P_REXB, args[0], args[1]); > break; > case INDEX_op_ext16u_i32: > - tcg_out_modrm(s, 0xb7 | P_EXT, args[0], args[1]); > - break; > - case INDEX_op_ext8u_i64: > - tcg_out_modrm(s, 0xb6 | P_EXT | P_REXW, args[0], args[1]); > - break; > case INDEX_op_ext16u_i64: > - tcg_out_modrm(s, 0xb7 | P_EXT | P_REXW, args[0], args[1]); > + tcg_out_modrm(s, 0xb7 | P_EXT, args[0], args[1]); > break; > case INDEX_op_ext32u_i64: > tcg_out_modrm(s, 0x8b, args[0], args[1]); This part looks fine. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net