diff options
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac index 05cdaf8e..fac5f7a0 100644 --- a/configure.ac +++ b/configure.ac @@ -1079,11 +1079,42 @@ fi # +# Check whether GCC assembler needs "-Wa,--divide" to correctly handle +# constant division +# +if test $amd64_as_feature_detection = yes; then + AC_CACHE_CHECK([whether GCC assembler handles division correctly], + [gcry_cv_gcc_as_const_division_ok], + [gcry_cv_gcc_as_const_division_ok=no + AC_COMPILE_IFELSE([AC_LANG_SOURCE( + [[__asm__("xorl \$(123456789/12345678), %ebp;\n\t");]])], + [gcry_cv_gcc_as_const_division_ok=yes])]) + if test "$gcry_cv_gcc_as_const_division_ok" = "no" ; then + # + # Add '-Wa,--divide' to CPPFLAGS and try check again. + # + _gcc_cppflags_save="$CPPFLAGS" + CPPFLAGS="$CPPFLAGS -Wa,--divide" + AC_CACHE_CHECK([whether GCC assembler handles division correctly with "-Wa,--divide"], + [gcry_cv_gcc_as_const_division_with_wadivide_ok], + [gcry_cv_gcc_as_const_division_with_wadivide_ok=no + AC_COMPILE_IFELSE([AC_LANG_SOURCE( + [[__asm__("xorl \$(123456789/12345678), %ebp;\n\t");]])], + [gcry_cv_gcc_as_const_division_with_wadivide_ok=yes])]) + if test "$gcry_cv_gcc_as_const_division_ok_with_wadivide_ok" = "no" ; then + # '-Wa,--divide' did not work, restore old flags. + CPPFLAGS="$_gcc_cppflags_save" + fi + fi +fi + + +# # Check whether GCC assembler supports features needed for our amd64 # implementations # if test $amd64_as_feature_detection = yes; then - AC_CACHE_CHECK([whether GCC assembler is compatible for amd64 assembly implementations], + AC_CACHE_CHECK([whether GCC assembler is compatible for amd64 assembly implementations], [gcry_cv_gcc_amd64_platform_as_ok], [gcry_cv_gcc_amd64_platform_as_ok=no AC_COMPILE_IFELSE([AC_LANG_SOURCE( @@ -1096,6 +1127,11 @@ if test $amd64_as_feature_detection = yes; then "asmfunc:\n\t" ".size asmfunc,.-asmfunc;\n\t" ".type asmfunc,@function;\n\t" + /* Test if assembler allows use of '/' for constant division + * (Solaris/x86 issue). If previous constant division check + * and "-Wa,--divide" workaround failed, this causes assembly + * to be disable on this machine. */ + "xorl \$(123456789/12345678), %ebp;\n\t" );]])], [gcry_cv_gcc_amd64_platform_as_ok=yes])]) if test "$gcry_cv_gcc_amd64_platform_as_ok" = "yes" ; then |