mesa: Replace a priori knowledge of gcc builtins with configure tests.
Presumbly this will let clang and other compilers use the built-ins as
well.
Notice two changes specifically:
- in _mesa_next_pow_two_64(), always use __builtin_clzll and add a
static assertion that this is safe.
- in macros.h, remove the clang-specific definition since it should
be able to detect __builtin_unreachable in configure.
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com> [C bits]
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
diff --git a/configure.ac b/configure.ac
index bad1528..db134a2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -130,6 +130,15 @@
dnl Check for compiler builtins
AX_GCC_BUILTIN([__builtin_bswap32])
AX_GCC_BUILTIN([__builtin_bswap64])
+AX_GCC_BUILTIN([__builtin_clz])
+AX_GCC_BUILTIN([__builtin_clzll])
+AX_GCC_BUILTIN([__builtin_ctz])
+AX_GCC_BUILTIN([__builtin_expect])
+AX_GCC_BUILTIN([__builtin_ffs])
+AX_GCC_BUILTIN([__builtin_ffsll])
+AX_GCC_BUILTIN([__builtin_popcount])
+AX_GCC_BUILTIN([__builtin_popcountll])
+AX_GCC_BUILTIN([__builtin_unreachable])
AM_CONDITIONAL([GEN_ASM_OFFSETS], test "x$GEN_ASM_OFFSETS" = xyes)