Simplify SIMD make scripts

ax_ext.m4 no longer performs any CPU checks. Instead it just checks
if the the compile supports SIMD flags.

Runtime detection will choose the right methods base on CPU
instructions available.

Intel AVX support is still done through the build since it would
require a major refactoring of the code base to support it at runtime.
For now I added a configuration flag --enable-avx that can be used
to compile with AVX support.

Also use cpu intrinsics instead of __asm__

3 files changed, 31 insertions, 422 deletions

diff --git a/m4/ax_ext.m4 b/m4/ax_ext.m4
index c03ccef..95c4dbe 100644
--- a/m4/ax_ext.m4
+++ b/m4/ax_ext.m4
@@ -1,40 +1,7 @@
 #
-# Updated by KMG to support -DINTEL_SSE for GF-Complete
+# This macro is based on http://www.gnu.org/software/autoconf-archive/ax_ext.html
+# but simplified to do compile time SIMD checks only
 #
-# ===========================================================================
-#          http://www.gnu.org/software/autoconf-archive/ax_ext.html
-# ===========================================================================
-#
-# SYNOPSIS
-#
-#   AX_EXT
-#
-# DESCRIPTION
-#
-#   Find supported SIMD extensions by requesting cpuid. When an SIMD
-#   extension is found, the -m"simdextensionname" is added to SIMD_FLAGS if
-#   compiler supports it. For example, if "sse2" is available, then "-msse2"
-#   is added to SIMD_FLAGS.
-#
-#   This macro calls:
-#
-#     AC_SUBST(SIMD_FLAGS)
-#
-#   And defines:
-#
-#     HAVE_MMX / HAVE_SSE / HAVE_SSE2 / HAVE_SSE3 / HAVE_SSSE3 / HAVE_SSE4.1 / HAVE_SSE4.2 / HAVE_AVX
-#
-# LICENSE
-#
-#   Copyright (c) 2007 Christophe Tournayre <turn3r@users.sourceforge.net>
-#   Copyright (c) 2013 Michael Petch <mpetch@capp-sysware.com>
-#
-#   Copying and distribution of this file, with or without modification, are
-#   permitted in any medium without royalty provided the copyright notice
-#   and this notice are preserved. This file is offered as-is, without any
-#   warranty.
-
-#serial 12
 
 AC_DEFUN([AX_EXT],
 [
@@ -45,263 +12,63 @@ AC_DEFUN([AX_EXT],
       AC_DEFINE(HAVE_ARCH_AARCH64,,[targeting AArch64])
       SIMD_FLAGS="$SIMD_FLAGS -DARCH_AARCH64"
 
-      AC_CACHE_CHECK([whether NEON is supported], [ax_cv_have_neon_ext],
-          [
-            # TODO: detect / cross-compile
-            ax_cv_have_neon_ext=yes
-          ])
-      AC_CACHE_CHECK([whether cryptographic extension is supported], [ax_cv_have_arm_crypt_ext],
-          [
-            # TODO: detect / cross-compile
-            ax_cv_have_arm_crypt_ext=yes
-          ])
-
-      if test "$ax_cv_have_arm_crypt_ext" = yes; then
-        AC_DEFINE(HAVE_ARM_CRYPT_EXT,,[Support ARM cryptographic extension])
-      fi
-
+      AC_CACHE_CHECK([whether NEON is enabled], [ax_cv_have_neon_ext], [ax_cv_have_neon_ext=yes])
       if test "$ax_cv_have_neon_ext" = yes; then
-        AC_DEFINE(HAVE_NEON,,[Support NEON instructions])
+        AX_CHECK_COMPILE_FLAG(-march=armv8-a+simd, [SIMD_FLAGS="$SIMD_FLAGS -march=armv8-a+simd -DARM_NEON"], [ax_cv_have_neon_ext=no])
       fi
-
-      if test "$ax_cv_have_arm_crypt_ext" = yes && test "$ax_cv_have_neon_ext" = yes; then
-          AX_CHECK_COMPILE_FLAG(-march=armv8-a+simd+crypto,
-                                SIMD_FLAGS="$SIMD_FLAGS -march=armv8-a+simd+crypto -DARM_CRYPT -DARM_NEON", [])
-      elif test "$ax_cv_have_arm_crypt_ext" = yes; then
-          AX_CHECK_COMPILE_FLAG(-march=armv8-a+crypto,
-                                SIMD_FLAGS="$SIMD_FLAGS -march=armv8-a+crypto -DARM_CRYPT", [])
-      elif test "$ax_cv_have_neon_ext" = yes; then
-          AX_CHECK_COMPILE_FLAG(-march=armv8-a+simd,
-                                SIMD_FLAGS="$SIMD_FLAGS -march=armv8-a+simd -DARM_NEON", [])
-      fi
-    ;;
+      ;;
 
     arm*)
-      AC_CACHE_CHECK([whether NEON is supported], [ax_cv_have_neon_ext],
-          [
-            # TODO: detect / cross-compile
-            ax_cv_have_neon_ext=yes
-          ])
-
+      AC_CACHE_CHECK([whether NEON is enabled], [ax_cv_have_neon_ext], [ax_cv_have_neon_ext=yes])
       if test "$ax_cv_have_neon_ext" = yes; then
-        AC_DEFINE(HAVE_NEON,,[Support NEON instructions])
-        AX_CHECK_COMPILE_FLAG(-mfpu=neon,
-                                SIMD_FLAGS="$SIMD_FLAGS -mfpu=neon -DARM_NEON", [])
+        AX_CHECK_COMPILE_FLAG(-mfpu=neon, [SIMD_FLAGS="$SIMD_FLAGS -mfpu=neon -DARM_NEON"], [ax_cv_have_neon_ext=no])
       fi
-    ;;
+      ;;
 
     powerpc*)
-      AC_CACHE_CHECK([whether altivec is supported], [ax_cv_have_altivec_ext],
-          [
-            if test `/usr/sbin/sysctl -a 2>/dev/null| grep -c hw.optional.altivec` != 0; then
-                if test `/usr/sbin/sysctl -n hw.optional.altivec` = 1; then
-                  ax_cv_have_altivec_ext=yes
-                fi
-            fi
-          ])
-
-          if test "$ax_cv_have_altivec_ext" = yes; then
-            AC_DEFINE(HAVE_ALTIVEC,,[Support Altivec instructions])
-            AX_CHECK_COMPILE_FLAG(-faltivec, SIMD_FLAGS="$SIMD_FLAGS -faltivec", [])
-          fi
-    ;;
-
-
-    i[[3456]]86*|x86_64*|amd64*)
-
-      AC_REQUIRE([AX_GCC_X86_CPUID])
-      AC_REQUIRE([AX_GCC_X86_AVX_XGETBV])
-
-      AX_GCC_X86_CPUID(0x00000001)
-      ecx=`echo $ax_cv_gcc_x86_cpuid_0x00000001 | cut -d ":" -f 3`
-      edx=`echo $ax_cv_gcc_x86_cpuid_0x00000001 | cut -d ":" -f 4`
-
-      AC_CACHE_CHECK([whether mmx is supported], [ax_cv_have_mmx_ext],
-      [
-        ax_cv_have_mmx_ext=no
-        if test "$((0x$edx>>23&0x01))" = 1; then
-          ax_cv_have_mmx_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether sse is supported], [ax_cv_have_sse_ext],
-      [
-        ax_cv_have_sse_ext=no
-        if test "$((0x$edx>>25&0x01))" = 1; then
-          ax_cv_have_sse_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether sse2 is supported], [ax_cv_have_sse2_ext],
-      [
-        ax_cv_have_sse2_ext=no
-        if test "$((0x$edx>>26&0x01))" = 1; then
-          ax_cv_have_sse2_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether sse3 is supported], [ax_cv_have_sse3_ext],
-      [
-        ax_cv_have_sse3_ext=no
-        if test "$((0x$ecx&0x01))" = 1; then
-          ax_cv_have_sse3_ext=yes
-        fi
-      ])
-      
-      AC_CACHE_CHECK([whether pclmuldq is supported], [ax_cv_have_pclmuldq_ext],
-      [
-        ax_cv_have_pclmuldq_ext=no
-        if test "$((0x$ecx>>1&0x01))" = 1; then
-          ax_cv_have_pclmuldq_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether ssse3 is supported], [ax_cv_have_ssse3_ext],
-      [
-        ax_cv_have_ssse3_ext=no
-        if test "$((0x$ecx>>9&0x01))" = 1; then
-          ax_cv_have_ssse3_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether sse4.1 is supported], [ax_cv_have_sse41_ext],
-      [
-        ax_cv_have_sse41_ext=no
-        if test "$((0x$ecx>>19&0x01))" = 1; then
-          ax_cv_have_sse41_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether sse4.2 is supported], [ax_cv_have_sse42_ext],
-      [
-        ax_cv_have_sse42_ext=no
-        if test "$((0x$ecx>>20&0x01))" = 1; then
-          ax_cv_have_sse42_ext=yes
-        fi
-      ])
-
-      AC_CACHE_CHECK([whether avx is supported by processor], [ax_cv_have_avx_cpu_ext],
-      [
-        ax_cv_have_avx_cpu_ext=no
-        if test "$((0x$ecx>>28&0x01))" = 1; then
-          ax_cv_have_avx_cpu_ext=yes
-        fi
-      ])
-
-      if test x"$ax_cv_have_avx_cpu_ext" = x"yes"; then
-        AX_GCC_X86_AVX_XGETBV(0x00000000)
-
-        xgetbv_eax="0"
-        if test x"$ax_cv_gcc_x86_avx_xgetbv_0x00000000" != x"unknown"; then
-          xgetbv_eax=`echo $ax_cv_gcc_x86_avx_xgetbv_0x00000000 | cut -d ":" -f 1`
-        fi
-
-        AC_CACHE_CHECK([whether avx is supported by operating system], [ax_cv_have_avx_ext],
-        [
-          ax_cv_have_avx_ext=no
-
-          if test "$((0x$ecx>>27&0x01))" = 1; then
-            if test "$((0x$xgetbv_eax&0x6))" = 6; then
-              ax_cv_have_avx_ext=yes
-            fi
-          fi
-        ])
-        if test x"$ax_cv_have_avx_ext" = x"no"; then
-          AC_MSG_WARN([Your processor supports AVX, but your operating system doesn't])
-        fi
+      AC_CACHE_CHECK([whether altivec is enabled], [ax_cv_have_altivec_ext], [ax_cv_have_altivec_ext=yes])
+      if test "$ax_cv_have_altivec_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-faltivec, [SIMD_FLAGS="$SIMD_FLAGS -faltivec"], [ax_cv_have_altivec_ext=no])
       fi
+      ;;
 
-      if test "$ax_cv_have_mmx_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-mmmx, ax_cv_support_mmx_ext=yes, [])
-        if test x"$ax_cv_support_mmx_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -mmmx"
-          AC_DEFINE(HAVE_MMX,,[Support mmx instructions])
-        else
-          AC_MSG_WARN([Your processor supports mmx instructions but not your compiler, can you try another compiler?])
-        fi
-      fi
+    i[[3456]]86*|x86_64*|amd64*)
 
+      AC_CACHE_CHECK([whether sse is enabled], [ax_cv_have_sse_ext], [ax_cv_have_sse_ext=yes])
       if test "$ax_cv_have_sse_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-msse, ax_cv_support_sse_ext=yes, [])
-        if test x"$ax_cv_support_sse_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -msse -DINTEL_SSE"
-          AC_DEFINE(HAVE_SSE,,[Support SSE (Streaming SIMD Extensions) instructions])
-        else
-          AC_MSG_WARN([Your processor supports sse instructions but not your compiler, can you try another compiler?])
-        fi
+        AX_CHECK_COMPILE_FLAG(-msse, [SIMD_FLAGS="$SIMD_FLAGS -msse -DINTEL_SSE"], [ax_cv_have_sse_ext=no])
       fi
 
+      AC_CACHE_CHECK([whether sse2 is enabled], [ax_cv_have_sse2_ext], [ax_cv_have_sse2_ext=yes])
       if test "$ax_cv_have_sse2_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-msse2, ax_cv_support_sse2_ext=yes, [])
-        if test x"$ax_cv_support_sse2_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -msse2 -DINTEL_SSE2"
-          AC_DEFINE(HAVE_SSE2,,[Support SSE2 (Streaming SIMD Extensions 2) instructions])
-        else
-          AC_MSG_WARN([Your processor supports sse2 instructions but not your compiler, can you try another compiler?])
-        fi
+        AX_CHECK_COMPILE_FLAG(-msse2, [SIMD_FLAGS="$SIMD_FLAGS -msse2 -DINTEL_SSE2"], [ax_cv_have_sse2_ext=no])
       fi
 
+      AC_CACHE_CHECK([whether sse3 is enabled], [ax_cv_have_sse3_ext], [ax_cv_have_sse3_ext=yes])
       if test "$ax_cv_have_sse3_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-msse3, ax_cv_support_sse3_ext=yes, [])
-        if test x"$ax_cv_support_sse3_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -msse3 -DINTEL_SSE3"
-          AC_DEFINE(HAVE_SSE3,,[Support SSE3 (Streaming SIMD Extensions 3) instructions])
-        else
-          AC_MSG_WARN([Your processor supports sse3 instructions but not your compiler, can you try another compiler?])
-        fi
-      fi
-      
-      if test "$ax_cv_have_pclmuldq_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-mpclmul, ax_cv_support_pclmuldq_ext=yes, [])
-        if test x"$ax_cv_support_pclmuldq_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -mpclmul -DINTEL_SSE4_PCLMUL"
-          AC_DEFINE(HAVE_PCLMULDQ,,[Support (PCLMULDQ) Carry-Free Muliplication])
-        else
-          AC_MSG_WARN([Your processor supports pclmuldq instructions but not your compiler, can you try another compiler?])
-        fi
+        AX_CHECK_COMPILE_FLAG(-msse3, [SIMD_FLAGS="$SIMD_FLAGS -msse3 -DINTEL_SSE3"], [ax_cv_have_sse3_ext=no])
       fi
 
+      AC_CACHE_CHECK([whether ssse3 is enabled], [ax_cv_have_ssse3_ext], [ax_cv_have_ssse3_ext=yes])
       if test "$ax_cv_have_ssse3_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-mssse3, ax_cv_support_ssse3_ext=yes, [])
-        if test x"$ax_cv_support_ssse3_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -mssse3 -DINTEL_SSSE3"
-          AC_DEFINE(HAVE_SSSE3,,[Support SSSE3 (Supplemental Streaming SIMD Extensions 3) instructions])
-        else
-          AC_MSG_WARN([Your processor supports ssse3 instructions but not your compiler, can you try another compiler?])
-        fi
+        AX_CHECK_COMPILE_FLAG(-mssse3, [SIMD_FLAGS="$SIMD_FLAGS -mssse3 -DINTEL_SSSE3"], [ax_cv_have_ssse3_ext=no])
       fi
 
-      if test "$ax_cv_have_sse41_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-msse4.1, ax_cv_support_sse41_ext=yes, [])
-        if test x"$ax_cv_support_sse41_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -msse4.1 -DINTEL_SSE4"
-          AC_DEFINE(HAVE_SSE4_1,,[Support SSSE4.1 (Streaming SIMD Extensions 4.1) instructions])
-        else
-          AC_MSG_WARN([Your processor supports sse4.1 instructions but not your compiler, can you try another compiler?])
-        fi
+      AC_CACHE_CHECK([whether pclmuldq is enabled], [ax_cv_have_pclmuldq_ext], [ax_cv_have_pclmuldq_ext=yes])
+      if test "$ax_cv_have_pclmuldq_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-mpclmul, [SIMD_FLAGS="$SIMD_FLAGS -mpclmul -DINTEL_SSE4_PCLMUL"], [ax_cv_have_pclmuldq_ext=no])
       fi
 
-      if test "$ax_cv_have_sse42_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-msse4.2, ax_cv_support_sse42_ext=yes, [])
-        if test x"$ax_cv_support_sse42_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -msse4.2 -DINTEL_SSE4"
-          AC_DEFINE(HAVE_SSE4_2,,[Support SSSE4.2 (Streaming SIMD Extensions 4.2) instructions])
-        else
-          AC_MSG_WARN([Your processor supports sse4.2 instructions but not your compiler, can you try another compiler?])
-        fi
+      AC_CACHE_CHECK([whether sse4.1 is enabled], [ax_cv_have_sse41_ext], [ax_cv_have_sse41_ext=yes])
+      if test "$ax_cv_have_sse41_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse4.1, [SIMD_FLAGS="$SIMD_FLAGS -msse4.1 -DINTEL_SSE4"], [ax_cv_have_sse41_ext=no])
       fi
 
-      if test "$ax_cv_have_avx_ext" = yes; then
-        AX_CHECK_COMPILE_FLAG(-mavx, ax_cv_support_avx_ext=yes, [])
-        if test x"$ax_cv_support_avx_ext" = x"yes"; then
-          SIMD_FLAGS="$SIMD_FLAGS -mavx"
-          AC_DEFINE(HAVE_AVX,,[Support AVX (Advanced Vector Extensions) instructions])
-        else
-          AC_MSG_WARN([Your processor supports avx instructions but not your compiler, can you try another compiler?])
-        fi
+      AC_CACHE_CHECK([whether sse4.2 is enabled], [ax_cv_have_sse42_ext], [ax_cv_have_sse42_ext=yes])
+      if test "$ax_cv_have_sse42_ext" = yes; then
+        AX_CHECK_COMPILE_FLAG(-msse4.2, [SIMD_FLAGS="$SIMD_FLAGS -msse4.2 -DINTEL_SSE4"], [ax_cv_have_sse42_ext=no])
       fi
-
-  ;;
+      ;;
   esac
 
   AC_SUBST(SIMD_FLAGS)
diff --git a/m4/ax_gcc_x86_avx_xgetbv.m4 b/m4/ax_gcc_x86_avx_xgetbv.m4
deleted file mode 100644
index 0624eeb..0000000
--- a/m4/ax_gcc_x86_avx_xgetbv.m4
+++ /dev/null
@@ -1,79 +0,0 @@
-# ===========================================================================
-#   http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_avx_xgetbv.html
-# ===========================================================================
-#
-# SYNOPSIS
-#
-#   AX_GCC_X86_AVX_XGETBV
-#
-# DESCRIPTION
-#
-#   On later x86 processors with AVX SIMD support, with gcc or a compiler
-#   that has a compatible syntax for inline assembly instructions, run a
-#   small program that executes the xgetbv instruction with input OP. This
-#   can be used to detect if the OS supports AVX instruction usage.
-#
-#   On output, the values of the eax and edx registers are stored as
-#   hexadecimal strings as "eax:edx" in the cache variable
-#   ax_cv_gcc_x86_avx_xgetbv.
-#
-#   If the xgetbv instruction fails (because you are running a
-#   cross-compiler, or because you are not using gcc, or because you are on
-#   a processor that doesn't have this instruction),
-#   ax_cv_gcc_x86_avx_xgetbv_OP is set to the string "unknown".
-#
-#   This macro mainly exists to be used in AX_EXT.
-#
-# LICENSE
-#
-#   Copyright (c) 2013 Michael Petch <mpetch@capp-sysware.com>
-#
-#   This program is free software: you can redistribute it and/or modify it
-#   under the terms of the GNU General Public License as published by the
-#   Free Software Foundation, either version 3 of the License, or (at your
-#   option) any later version.
-#
-#   This program 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 General
-#   Public License for more details.
-#
-#   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
-#
-#   As a special exception, the respective Autoconf Macro's copyright owner
-#   gives unlimited permission to copy, distribute and modify the configure
-#   scripts that are the output of Autoconf when processing the Macro. You
-#   need not follow the terms of the GNU General Public License when using
-#   or distributing such scripts, even though portions of the text of the
-#   Macro appear in them. The GNU General Public License (GPL) does govern
-#   all other use of the material that constitutes the Autoconf Macro.
-#
-#   This special exception to the GPL applies to versions of the Autoconf
-#   Macro released by the Autoconf Archive. When you make and distribute a
-#   modified version of the Autoconf Macro, you may extend this special
-#   exception to the GPL to apply to your modified version as well.
-
-#serial 1
-
-AC_DEFUN([AX_GCC_X86_AVX_XGETBV],
-[AC_REQUIRE([AC_PROG_CC])
-AC_LANG_PUSH([C])
-AC_CACHE_CHECK(for x86-AVX xgetbv $1 output, ax_cv_gcc_x86_avx_xgetbv_$1,
- [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
-     int op = $1, eax, edx;
-     FILE *f;
-      /* Opcodes for xgetbv */
-      __asm__(".byte 0x0f, 0x01, 0xd0"
-        : "=a" (eax), "=d" (edx)
-        : "c" (op));
-     f = fopen("conftest_xgetbv", "w"); if (!f) return 1;
-     fprintf(f, "%x:%x\n", eax, edx);
-     fclose(f);
-     return 0;
-])],
-     [ax_cv_gcc_x86_avx_xgetbv_$1=`cat conftest_xgetbv`; rm -f conftest_xgetbv],
-     [ax_cv_gcc_x86_avx_xgetbv_$1=unknown; rm -f conftest_xgetbv],
-     [ax_cv_gcc_x86_avx_xgetbv_$1=unknown])])
-AC_LANG_POP([C])
-])
diff --git a/m4/ax_gcc_x86_cpuid.m4 b/m4/ax_gcc_x86_cpuid.m4
deleted file mode 100644
index 7d46fee..0000000
--- a/m4/ax_gcc_x86_cpuid.m4
+++ /dev/null
@@ -1,79 +0,0 @@
-# ===========================================================================
-#     http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html
-# ===========================================================================
-#
-# SYNOPSIS
-#
-#   AX_GCC_X86_CPUID(OP)
-#
-# DESCRIPTION
-#
-#   On Pentium and later x86 processors, with gcc or a compiler that has a
-#   compatible syntax for inline assembly instructions, run a small program
-#   that executes the cpuid instruction with input OP. This can be used to
-#   detect the CPU type.
-#
-#   On output, the values of the eax, ebx, ecx, and edx registers are stored
-#   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
-#   ax_cv_gcc_x86_cpuid_OP.
-#
-#   If the cpuid instruction fails (because you are running a
-#   cross-compiler, or because you are not using gcc, or because you are on
-#   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
-#   is set to the string "unknown".
-#
-#   This macro mainly exists to be used in AX_GCC_ARCHFLAG.
-#
-# LICENSE
-#
-#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
-#   Copyright (c) 2008 Matteo Frigo
-#
-#   This program is free software: you can redistribute it and/or modify it
-#   under the terms of the GNU General Public License as published by the
-#   Free Software Foundation, either version 3 of the License, or (at your
-#   option) any later version.
-#
-#   This program 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 General
-#   Public License for more details.
-#
-#   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
-#
-#   As a special exception, the respective Autoconf Macro's copyright owner
-#   gives unlimited permission to copy, distribute and modify the configure
-#   scripts that are the output of Autoconf when processing the Macro. You
-#   need not follow the terms of the GNU General Public License when using
-#   or distributing such scripts, even though portions of the text of the
-#   Macro appear in them. The GNU General Public License (GPL) does govern
-#   all other use of the material that constitutes the Autoconf Macro.
-#
-#   This special exception to the GPL applies to versions of the Autoconf
-#   Macro released by the Autoconf Archive. When you make and distribute a
-#   modified version of the Autoconf Macro, you may extend this special
-#   exception to the GPL to apply to your modified version as well.
-
-#serial 7
-
-AC_DEFUN([AX_GCC_X86_CPUID],
-[AC_REQUIRE([AC_PROG_CC])
-AC_LANG_PUSH([C])
-AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
- [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
-     int op = $1, eax, ebx, ecx, edx;
-     FILE *f;
-      __asm__("cpuid"
-        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
-        : "a" (op));
-     f = fopen("conftest_cpuid", "w"); if (!f) return 1;
-     fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
-     fclose(f);
-     return 0;
-])],
-     [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
-     [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
-     [ax_cv_gcc_x86_cpuid_$1=unknown])])
-AC_LANG_POP([C])
-])