libm: Provide fallback definitions for isnan() and isinf()

Signed-off-by: Martin Storsjö <martin@martin.st>

configure

@@ -1093,6 +1093,8 @@ HAVE_LIST="
     inet_aton
     inline_asm
     isatty
+    isinf
+    isnan
     jack_port_get_latency_range
     ldbrx
     libdc1394_1
@@ -2922,6 +2924,8 @@ enabled vaapi && require vaapi va/va.h vaInitialize -lva
 check_mathfunc cbrtf
 check_mathfunc exp2
 check_mathfunc exp2f
+check_mathfunc isinf
+check_mathfunc isnan
 check_mathfunc llrint
 check_mathfunc llrintf
 check_mathfunc log2

libavutil/libm.h

@@ -27,6 +27,7 @@
 #include <math.h>
 #include "config.h"
 #include "attributes.h"
+#include "intfloat.h"
 
 #if !HAVE_CBRTF
 static av_always_inline float cbrtf(float x)
@@ -45,6 +46,26 @@ static av_always_inline float cbrtf(float x)
 #define exp2f(x) ((float)exp2(x))
 #endif /* HAVE_EXP2F */
 
+#if !HAVE_ISINF
+static av_always_inline av_const int isinf(float x)
+{
+    uint32_t v = av_float2int(x);
+    if ((v & 0x7f800000) != 0x7f800000)
+        return 0;
+    return !(v & 0x007fffff);
+}
+#endif /* HAVE_ISINF */
+
+#if !HAVE_ISNAN
+static av_always_inline av_const int isnan(float x)
+{
+    uint32_t v = av_float2int(x);
+    if ((v & 0x7f800000) != 0x7f800000)
+        return 0;
+    return v & 0x007fffff;
+}
+#endif /* HAVE_ISNAN */
+
 #if !HAVE_LLRINT
 #undef llrint
 #define llrint(x) ((long long)rint(x))