| Message ID | 20100106010536.9092BCBA@are.twiddle.net |
|---|---|
| State | New |
| Headers | show |
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 <rth@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.
On 01/14/2010 07:57 AM, Aurelien Jarno wrote: > 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<rth@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. Pardon? Do you mean the inc/dec tests? Otherwise I don't see what "above tests again" you're talking about. I am looking to handle more than 0xff, 0xffff with the new test in gen_arithi64 -- 0x1234 is an appropriate mask to shorten to 32-bit AND as well. I have no idea if that answers your question. r~
On Thu, Jan 14, 2010 at 08:05:58AM -0800, Richard Henderson wrote: > On 01/14/2010 07:57 AM, Aurelien Jarno wrote: > >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<rth@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. > > Pardon? Do you mean the inc/dec tests? Otherwise I don't see what > "above tests again" you're talking about. > > I am looking to handle more than 0xff, 0xffff with the new test in > gen_arithi64 -- 0x1234 is an appropriate mask to shorten to 32-bit > AND as well. I have no idea if that answers your question. > Yes it does, I missed that fact. Viewing your patch on this side gives it more sense. I have applied it.
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); + } 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 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 <rth@twiddle.net> --- tcg/x86_64/tcg-target.c | 26 ++++++++------------------ 1 files changed, 8 insertions(+), 18 deletions(-)