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| author | Brad Smith <brad@comstyle.com> | 2013-10-17 23:22:02 -0400 |
|---|---|---|
| committer | Søren Sandmann Pedersen <ssp@redhat.com> | 2013-11-01 20:14:33 -0400 |
| commit | 8ef7e0d18e00291da14c69d3034896235875d019 (patch) | |
| tree | 266dd98a24bf71c0b5d0beb0514a3270972c265d | |
| parent | 3c2f4b651747c1ac484c39d5128cae5483094342 (diff) | |
Fix pixman build with older GCC releases
The following patch fixes building pixman with older GCC releases
such as GCC 3.3 and older (OpenBSD; some older archs use GCC 3.3.6)
by changing the method of detecting the presence of __builtin_clz
to utilizing an autoconf check to determine its presence. Compilers
that pretend to be GCC, implement __builtin_clz and are already
utilizing the intrinsic include LLVM/Clang, Open64, EKOPath and
PCC.
| -rw-r--r-- | configure.ac | 16 | ||||
| -rw-r--r-- | pixman/pixman-matrix.c | 2 |
2 files changed, 17 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac index 8a3b6226..5ccc267c 100644 --- a/configure.ac +++ b/configure.ac @@ -1044,6 +1044,22 @@ fi AC_MSG_RESULT($support_for_float128) +dnl ===================================== +dnl __builtin_clz + +support_for_builtin_clz=no + +AC_MSG_CHECKING(for __builtin_clz) +AC_LINK_IFELSE([AC_LANG_SOURCE([[ +unsigned int x = 11; int main (void) { return __builtin_clz(x); } +]])], support_for_builtin_clz=yes) + +if test x$support_for_builtin_clz = xyes; then + AC_DEFINE([HAVE_BUILTIN_CLZ], [], [Whether the compiler supports __builtin_clz]) +fi + +AC_MSG_RESULT($support_for_builtin_clz) + dnl ================== dnl libpng diff --git a/pixman/pixman-matrix.c b/pixman/pixman-matrix.c index 89b96826..4032c137 100644 --- a/pixman/pixman-matrix.c +++ b/pixman/pixman-matrix.c @@ -37,7 +37,7 @@ static force_inline int count_leading_zeros (uint32_t x) { -#ifdef __GNUC__ +#ifdef HAVE_BUILTIN_CLZ return __builtin_clz (x); #else int n = 0; |