From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:44583) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hJ45t-0005Ez-5d for qemu-devel@nongnu.org; Tue, 23 Apr 2019 18:40:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hJ3uU-00061Z-3P for qemu-devel@nongnu.org; Tue, 23 Apr 2019 18:29:07 -0400 Received: from mail-pl1-x643.google.com ([2607:f8b0:4864:20::643]:35089) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hJ3uT-0005z4-IO for qemu-devel@nongnu.org; Tue, 23 Apr 2019 18:29:06 -0400 Received: by mail-pl1-x643.google.com with SMTP id w24so8212717plp.2 for ; Tue, 23 Apr 2019 15:29:05 -0700 (PDT) References: <20190420073442.7488-1-richard.henderson@linaro.org> <20190420073442.7488-20-richard.henderson@linaro.org> <0bd7fd6a-1fcb-ac0c-b4bf-7b04ada4443c@redhat.com> From: Richard Henderson Message-ID: Date: Tue, 23 Apr 2019 15:29:01 -0700 MIME-Version: 1.0 In-Reply-To: <0bd7fd6a-1fcb-ac0c-b4bf-7b04ada4443c@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 19/38] tcg: Add support for integer absolute value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , David Hildenbrand , qemu-devel@nongnu.org, "Edgar E. Iglesias" On 4/23/19 3:09 PM, Philippe Mathieu-Daudé wrote: > On 4/23/19 8:37 PM, David Hildenbrand wrote: >> On 20.04.19 09:34, Richard Henderson wrote: >>> Remove a function of the same name from target/arm/. >>> Use a branchless implementation of abs that gcc uses for x86. >>> >>> Signed-off-by: Richard Henderson >>> --- >>> tcg/tcg-op.h | 5 +++++ >>> target/arm/translate.c | 10 ---------- >>> tcg/tcg-op.c | 20 ++++++++++++++++++++ >>> 3 files changed, 25 insertions(+), 10 deletions(-) >>> >>> diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h >>> index 472b73cb38..660fe205d0 100644 >>> --- a/tcg/tcg-op.h >>> +++ b/tcg/tcg-op.h >>> @@ -335,6 +335,7 @@ void tcg_gen_smin_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2); >>> void tcg_gen_smax_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2); >>> void tcg_gen_umin_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2); >>> void tcg_gen_umax_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2); >>> +void tcg_gen_abs_i32(TCGv_i32, TCGv_i32); >>> >>> static inline void tcg_gen_discard_i32(TCGv_i32 arg) >>> { >>> @@ -534,6 +535,7 @@ void tcg_gen_smin_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2); >>> void tcg_gen_smax_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2); >>> void tcg_gen_umin_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2); >>> void tcg_gen_umax_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2); >>> +void tcg_gen_abs_i64(TCGv_i64, TCGv_i64); >>> >>> #if TCG_TARGET_REG_BITS == 64 >>> static inline void tcg_gen_discard_i64(TCGv_i64 arg) >>> @@ -973,6 +975,7 @@ void tcg_gen_nor_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b); >>> void tcg_gen_eqv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b); >>> void tcg_gen_not_vec(unsigned vece, TCGv_vec r, TCGv_vec a); >>> void tcg_gen_neg_vec(unsigned vece, TCGv_vec r, TCGv_vec a); >>> +void tcg_gen_abs_vec(unsigned vece, TCGv_vec r, TCGv_vec a); >>> void tcg_gen_ssadd_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b); >>> void tcg_gen_usadd_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b); >>> void tcg_gen_sssub_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b); >>> @@ -1019,6 +1022,7 @@ void tcg_gen_stl_vec(TCGv_vec r, TCGv_ptr base, TCGArg offset, TCGType t); >>> #define tcg_gen_addi_tl tcg_gen_addi_i64 >>> #define tcg_gen_sub_tl tcg_gen_sub_i64 >>> #define tcg_gen_neg_tl tcg_gen_neg_i64 >>> +#define tcg_gen_abs_tl tcg_gen_abs_i64 >>> #define tcg_gen_subfi_tl tcg_gen_subfi_i64 >>> #define tcg_gen_subi_tl tcg_gen_subi_i64 >>> #define tcg_gen_and_tl tcg_gen_and_i64 >>> @@ -1131,6 +1135,7 @@ void tcg_gen_stl_vec(TCGv_vec r, TCGv_ptr base, TCGArg offset, TCGType t); >>> #define tcg_gen_addi_tl tcg_gen_addi_i32 >>> #define tcg_gen_sub_tl tcg_gen_sub_i32 >>> #define tcg_gen_neg_tl tcg_gen_neg_i32 >>> +#define tcg_gen_abs_tl tcg_gen_abs_i32 >>> #define tcg_gen_subfi_tl tcg_gen_subfi_i32 >>> #define tcg_gen_subi_tl tcg_gen_subi_i32 >>> #define tcg_gen_and_tl tcg_gen_and_i32 >>> diff --git a/target/arm/translate.c b/target/arm/translate.c >>> index 83a008e945..721171794d 100644 >>> --- a/target/arm/translate.c >>> +++ b/target/arm/translate.c >>> @@ -603,16 +603,6 @@ static void gen_sar(TCGv_i32 dest, TCGv_i32 t0, TCGv_i32 t1) >>> tcg_temp_free_i32(tmp1); >>> } >>> >>> -static void tcg_gen_abs_i32(TCGv_i32 dest, TCGv_i32 src) >>> -{ >>> - TCGv_i32 c0 = tcg_const_i32(0); >>> - TCGv_i32 tmp = tcg_temp_new_i32(); >>> - tcg_gen_neg_i32(tmp, src); >>> - tcg_gen_movcond_i32(TCG_COND_GT, dest, src, c0, src, tmp); >>> - tcg_temp_free_i32(c0); >>> - tcg_temp_free_i32(tmp); >>> -} >>> - >>> static void shifter_out_im(TCGv_i32 var, int shift) >>> { >>> if (shift == 0) { >>> diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c >>> index a00d1df37e..0ac291f1c4 100644 >>> --- a/tcg/tcg-op.c >>> +++ b/tcg/tcg-op.c >>> @@ -1091,6 +1091,16 @@ void tcg_gen_umax_i32(TCGv_i32 ret, TCGv_i32 a, TCGv_i32 b) >>> tcg_gen_movcond_i32(TCG_COND_LTU, ret, a, b, b, a); >>> } >>> >>> +void tcg_gen_abs_i32(TCGv_i32 ret, TCGv_i32 a) >>> +{ >>> + TCGv_i32 t = tcg_temp_new_i32(); >>> + >>> + tcg_gen_sari_i32(t, a, 31); >>> + tcg_gen_xor_i32(ret, a, t); >>> + tcg_gen_sub_i32(ret, ret, t); >>> + tcg_temp_free_i32(t); >>> +} >>> + >>> /* 64-bit ops */ >>> >>> #if TCG_TARGET_REG_BITS == 32 >>> @@ -2548,6 +2558,16 @@ void tcg_gen_umax_i64(TCGv_i64 ret, TCGv_i64 a, TCGv_i64 b) >>> tcg_gen_movcond_i64(TCG_COND_LTU, ret, a, b, b, a); >>> } >>> >>> +void tcg_gen_abs_i64(TCGv_i64 ret, TCGv_i64 a) >>> +{ >>> + TCGv_i64 t = tcg_temp_new_i64(); >>> + >>> + tcg_gen_sari_i64(t, a, 63); >>> + tcg_gen_xor_i64(ret, a, t); >>> + tcg_gen_sub_i64(ret, ret, t); >>> + tcg_temp_free_i64(t); >>> +} >>> + >>> /* Size changing operations. */ >>> >>> void tcg_gen_extrl_i64_i32(TCGv_i32 ret, TCGv_i64 arg) >>> >> >> Nice trick > > Per commit 7dcfb0897b99, I think it's worth a: > > Inspired-by: Edgar E. Iglesias *shrug* As per the comment, I got the sequence from gcc -O2 -S. r~