x86_64: Optimize sincos where sin/cos is optimized (bug 29193)

The compiler may substitute calls to sin or cos with calls to sincos, thus
we should have the same optimized implementations for sincos.  The
optimized implementations may produce results that differ, that also makes
sure that the sincos call aggrees with the sin and cos calls.

sysdeps/ieee754/dbl-64/s_sincos.c

@@ -24,10 +24,15 @@
 #include <math-underflow.h>
 #include <libm-alias-double.h>
 
+#ifndef SECTION
+# define SECTION
+#endif
+
 #define IN_SINCOS
 #include "s_sin.c"
 
 void
+SECTION
 __sincos (double x, double *sinx, double *cosx)
 {
   mynumber u;
@@ -100,4 +105,6 @@ __sincos (double x, double *sinx, double *cosx)
 
   *sinx = *cosx = x / x;
 }
+#ifndef __sincos
 libm_alias_double (__sincos, sincos)
+#endif

sysdeps/x86_64/fpu/multiarch/Makefile

@@ -10,7 +10,8 @@ libm-sysdep_routines += s_ceil-sse4_1 s_ceilf-sse4_1 s_floor-sse4_1 \
 			s_trunc-sse4_1 s_truncf-sse4_1
 
 libm-sysdep_routines += e_exp-fma e_log-fma e_pow-fma s_atan-fma \
-			e_asin-fma e_atan2-fma s_sin-fma s_tan-fma
+			e_asin-fma e_atan2-fma s_sin-fma s_tan-fma \
+			s_sincos-fma
 
 CFLAGS-e_asin-fma.c = -mfma -mavx2
 CFLAGS-e_atan2-fma.c = -mfma -mavx2
@@ -20,6 +21,7 @@ CFLAGS-e_pow-fma.c = -mfma -mavx2
 CFLAGS-s_atan-fma.c = -mfma -mavx2
 CFLAGS-s_sin-fma.c = -mfma -mavx2
 CFLAGS-s_tan-fma.c = -mfma -mavx2
+CFLAGS-s_sincos-fma.c = -mfma -mavx2
 
 libm-sysdep_routines += s_sinf-sse2 s_cosf-sse2 s_sincosf-sse2
 
@@ -36,7 +38,8 @@ CFLAGS-s_cosf-fma.c = -mfma -mavx2
 CFLAGS-s_sincosf-fma.c = -mfma -mavx2
 
 libm-sysdep_routines += e_exp-fma4 e_log-fma4 e_pow-fma4 s_atan-fma4 \
-			e_asin-fma4 e_atan2-fma4 s_sin-fma4 s_tan-fma4
+			e_asin-fma4 e_atan2-fma4 s_sin-fma4 s_tan-fma4 \
+			s_sincos-fma4
 
 CFLAGS-e_asin-fma4.c = -mfma4
 CFLAGS-e_atan2-fma4.c = -mfma4
@@ -46,9 +49,11 @@ CFLAGS-e_pow-fma4.c = -mfma4
 CFLAGS-s_atan-fma4.c = -mfma4
 CFLAGS-s_sin-fma4.c = -mfma4
 CFLAGS-s_tan-fma4.c = -mfma4
+CFLAGS-s_sincos-fma4.c = -mfma4
 
 libm-sysdep_routines += e_exp-avx e_log-avx s_atan-avx \
-			e_atan2-avx s_sin-avx s_tan-avx
+			e_atan2-avx s_sin-avx s_tan-avx \
+			s_sincos-avx
 
 CFLAGS-e_atan2-avx.c = -msse2avx -DSSE2AVX
 CFLAGS-e_exp-avx.c = -msse2avx -DSSE2AVX
@@ -56,6 +61,7 @@ CFLAGS-e_log-avx.c = -msse2avx -DSSE2AVX
 CFLAGS-s_atan-avx.c = -msse2avx -DSSE2AVX
 CFLAGS-s_sin-avx.c = -msse2avx -DSSE2AVX
 CFLAGS-s_tan-avx.c = -msse2avx -DSSE2AVX
+CFLAGS-s_sincos-avx.c = -msse2avx -DSSE2AVX
 endif
 
 ifeq ($(subdir),mathvec)

sysdeps/x86_64/fpu/multiarch/s_sincos-avx.c

@@ -0,0 +1,3 @@
+#define __sincos __sincos_avx
+#define SECTION __attribute__ ((section (".text.avx")))
+#include <sysdeps/ieee754/dbl-64/s_sincos.c>

sysdeps/x86_64/fpu/multiarch/s_sincos-fma.c

@@ -0,0 +1,3 @@
+#define __sincos __sincos_fma
+#define SECTION __attribute__ ((section (".text.fma")))
+#include <sysdeps/ieee754/dbl-64/s_sincos.c>

sysdeps/x86_64/fpu/multiarch/s_sincos-fma4.c

@@ -0,0 +1,3 @@
+#define __sincos __sincos_fma4
+#define SECTION __attribute__ ((section (".text.fma4")))
+#include <sysdeps/ieee754/dbl-64/s_sincos.c>

sysdeps/x86_64/fpu/multiarch/s_sincos.c

@@ -0,0 +1,30 @@
+/* Multiple versions of sincos.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <libm-alias-double.h>
+
+extern void __redirect_sincos (double, double *, double *);
+
+#define SYMBOL_NAME sincos
+#include "ifunc-fma4.h"
+
+libc_ifunc_redirected (__redirect_sincos, __sincos, IFUNC_SELECTOR ());
+libm_alias_double (__sincos, sincos)
+
+#define __sincos __sincos_sse2
+#include <sysdeps/ieee754/dbl-64/s_sincos.c>