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Re: [Qemu-devel] [PATCH 4/8] tcg: Emit XORI as NOT for appropriate const
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH 4/8] tcg: Emit XORI as NOT for appropriate constants |
Date: |
Sat, 22 Sep 2012 21:52:04 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Sep 21, 2012 at 05:18:12PM -0700, Richard Henderson wrote:
> Note that xori_i64 failed to perform even the minimal
> optimizations promised by the README.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> tcg/tcg-op.h | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
> index fd16499..bcfb60b 100644
> --- a/tcg/tcg-op.h
> +++ b/tcg/tcg-op.h
> @@ -582,9 +582,12 @@ static inline void tcg_gen_xor_i32(TCGv_i32 ret,
> TCGv_i32 arg1, TCGv_i32 arg2)
>
> static inline void tcg_gen_xori_i32(TCGv_i32 ret, TCGv_i32 arg1, int32_t
> arg2)
> {
> - /* some cases can be optimized here */
> + /* Some cases can be optimized here. */
> if (arg2 == 0) {
> tcg_gen_mov_i32(ret, arg1);
> + } else if (arg2 == -1 && TCG_TARGET_HAS_not_i32) {
> + /* Don't recurse with tcg_gen_not_i32. */
> + tcg_gen_op2_i32(INDEX_op_not_i32, ret, arg1);
> } else {
> TCGv_i32 t0 = tcg_const_i32(arg2);
> tcg_gen_xor_i32(ret, arg1, t0);
> @@ -1206,9 +1209,17 @@ static inline void tcg_gen_xor_i64(TCGv_i64 ret,
> TCGv_i64 arg1, TCGv_i64 arg2)
>
> static inline void tcg_gen_xori_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t
> arg2)
> {
> - TCGv_i64 t0 = tcg_const_i64(arg2);
> - tcg_gen_xor_i64(ret, arg1, t0);
> - tcg_temp_free_i64(t0);
> + /* Some cases can be optimized here. */
> + if (arg2 == 0) {
> + tcg_gen_mov_i64(ret, arg1);
> + } else if (arg2 == -1 && TCG_TARGET_HAS_not_i64) {
> + /* Don't recurse with tcg_gen_not_i64. */
> + tcg_gen_op2_i64(INDEX_op_not_i64, ret, arg1);
> + } else {
> + TCGv_i64 t0 = tcg_const_i64(arg2);
> + tcg_gen_xor_i64(ret, arg1, t0);
> + tcg_temp_free_i64(t0);
> + }
> }
>
> static inline void tcg_gen_shl_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64
> arg2)
> --
> 1.7.11.4
>
Reviewed-by: Aurelien Jarno <address@hidden>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
- [Qemu-devel] [PATCH 0/8] Misc tcg improvements, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 1/8] tcg: Adjust descriptions of *cond opcodes, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 2/8] tcg: Emit ANDI as EXTU for appropriate constants, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 3/8] tcg: Optimize initial inputs for ori_i64, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 4/8] tcg: Emit XORI as NOT for appropriate constants, Richard Henderson, 2012/09/21
- Re: [Qemu-devel] [PATCH 4/8] tcg: Emit XORI as NOT for appropriate constants,
Aurelien Jarno <=
- [Qemu-devel] [PATCH 5/8] tcg: Implement concat*_i64 with deposit_i64, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 6/8] tcg: Add tcg_debug_assert, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 7/8] tcg: Sanity check deposit inputs, Richard Henderson, 2012/09/21
- [Qemu-devel] [PATCH 8/8] tcg: Sanity check goto_tb input, Richard Henderson, 2012/09/21