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| author | Alan Coopersmith <alan.coopersmith@oracle.com> | 2016-02-25 23:36:50 -0800 |
|---|---|---|
| committer | Alan Coopersmith <alan.coopersmith@oracle.com> | 2016-03-03 18:24:12 -0800 |
| commit | 490a25e6f8a4d2482af4364c700b68ad11a4d10b (patch) | |
| tree | 87cb9f917700aa3dbcc57bfcce012473257b1491 /configure.ac | |
| parent | 54ba591149f3a92c5a4a66e428ae2a33d1027053 (diff) | |
| download | xorg-lib-libXext-490a25e6f8a4d2482af4364c700b68ad11a4d10b.tar.gz | |
Use __builtin_popcountl if available to replace Ones() in XSecurity.c
If the compiler knows of a better algorithm for counting the number of
bits set in a word for the target CPU, let it use that, instead of the
classic algorithm optimized for PDP-6.
Tested for the range of values used in XSecurity.c and verified results
are the same from both:
for (unsigned long i = 0; i <= XSecurityAllAuthorizationAttributes; i++) {
printf("ones: %d\tpopcnt: %d\n", Ones(i), __builtin_popcountl(i));
}
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index 8efdd1f..5c241f5 100644 --- a/configure.ac +++ b/configure.ac @@ -5,6 +5,7 @@ AC_INIT([libXext], [1.3.3], [https://bugs.freedesktop.org/enter_bug.cgi?product=xorg], [libXext]) AC_CONFIG_SRCDIR([Makefile.am]) AC_CONFIG_HEADERS([config.h]) +AC_CONFIG_MACRO_DIR([m4]) # Initialize Automake AM_INIT_AUTOMAKE([foreign dist-bzip2]) @@ -38,6 +39,8 @@ AC_SUBST(XEXT_SOREV) # Obtain compiler/linker options for depedencies PKG_CHECK_MODULES(XEXT, [xproto >= 7.0.13] [x11 >= 1.6] [xextproto >= 7.1.99]) +AX_GCC_BUILTIN([__builtin_popcountl]) + # Allow checking code with lint, sparse, etc. XORG_WITH_LINT XORG_LINT_LIBRARY([Xext]) |