diff --git a/configure.in b/configure.in index 9591b5bbc5a..afe0cdc78ed 100644 --- a/configure.in +++ b/configure.in @@ -2094,6 +2094,27 @@ esac AC_MSG_CHECKING(for isinf in ) AC_TRY_LINK([#include ], [float f = 0.0; int r = isinf(f); return r], AC_MSG_RESULT(yes) + AC_MSG_CHECKING(whether isinf() is safe to use in C code) + AC_TRY_RUN([ +#include +int main() +{ + double a= 10.0; + double b= 1e308; + + return !isinf(a * b); +} +], + [AC_MSG_RESULT(yes)], + [AC_MSG_RESULT(no) + AC_DEFINE([HAVE_BROKEN_ISINF], [1], + [Define to 1 if isinf() uses 80-bit register for intermediate values]) + ], + [ +# Let's be optimistic when cross-compiling, since the only compiler known +# to be affected by this isinf() bug is GCC 4.3 on 32-bit x86. + AC_MSG_RESULT([[cross-compiling, assuming 'yes']]) + ]) AC_MSG_CHECKING(whether isinf() can be used in C++ code) AC_LANG_SAVE AC_LANG_CPLUSPLUS diff --git a/include/my_global.h b/include/my_global.h index 845ae042a42..7712696f633 100644 --- a/include/my_global.h +++ b/include/my_global.h @@ -797,9 +797,19 @@ typedef SOCKET_SIZE_TYPE size_socket; #endif #ifdef HAVE_ISINF -/* isinf() can be used in both C and C++ code */ -#define my_isinf(X) isinf(X) +/* Check if C compiler is affected by GCC bug #39228 */ +#if !defined(__cplusplus) && defined(HAVE_BROKEN_ISINF) +/* Force store/reload of the argument to/from a 64-bit double */ +static inline double my_isinf(double x) +{ + volatile double t= x; + return isinf(t); +} #else +/* System-provided isinf() is available and safe to use */ +#define my_isinf(X) isinf(X) +#endif +#else /* !HAVE_ISINF */ #define my_isinf(X) (!finite(X) && !isnan(X)) #endif