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Merge branch 'fix_stbimage_gcc_sse2' of https://github.com/rygorous/stb into working

pull/538/head
Sean Barrett 2017-03-18 18:34:17 -07:00
parent 24fa816116 3e17544873
commit 97c58e3891
1 changed files with 11 additions and 13 deletions
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24
stb_image.h
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@ -584,12 +584,14 @@ typedef unsigned char validate_uint32[sizeof(stbi__uint32)==4 ? 1 : -1];
#define STBI__X86_TARGET
#endif
#if defined(__GNUC__) && (defined(STBI__X86_TARGET) || defined(STBI__X64_TARGET)) && !defined(__SSE2__) && !defined(STBI_NO_SIMD)
// NOTE: not clear do we actually need this for the 64-bit path?
#if defined(__GNUC__) && defined(STBI__X86_TARGET) && !defined(__SSE2__) && !defined(STBI_NO_SIMD)
// gcc doesn't support sse2 intrinsics unless you compile with -msse2,
// (but compiling with -msse2 allows the compiler to use SSE2 everywhere;
// this is just broken and gcc are jerks for not fixing it properly
// http://www.virtualdub.org/blog/pivot/entry.php?id=363 )
// which in turn means it gets to use SSE2 everywhere. This is unfortunate,
// but previous attempts to provide the SSE2 functions with runtime
// detection caused numerous issues. The way architecture extensions are
// exposed in GCC/Clang is, sadly, not really suited for one-file libs.
// New behavior: if compiled with -msse2, we use SSE2 without any
// detection; if not, we don't use it at all.
#define STBI_NO_SIMD
#endif
@ -647,14 +649,10 @@ static int stbi__sse2_available()
static int stbi__sse2_available()
{
#if defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 // GCC 4.8 or later
// GCC 4.8+ has a nice way to do this
return __builtin_cpu_supports("sse2");
#else
// portable way to do this, preferably without using GCC inline ASM?
// just bail for now.
return 0;
#endif
// If we're even attempting to compile this on GCC/Clang, that means
// -msse2 is on, which means the compiler is allowed to use SSE2
// instructions at will, and so are we.
return 1;
}
#endif
#endif