>>>>> "Tom" == Tom Lane <t...@sss.pgh.pa.us> writes:
>> The reason it behaves oddly is this: on i387 FPU (and NOT on arm32 >> or on 32-bit i386 with a modern architecture specified to the >> compiler), the result of 1e200 * 1e180 is not in fact infinite, >> because it fits in an 80-bit long double. So __builtin_isinf reports >> that it is finite; but if it gets stored to memory as a double (e.g. >> to pass as a parameter to a function), it then becomes infinite. Tom> Ah-hah. Can we fix it by explicitly casting the argument of isinf Tom> to double? No; the generated code doesn't change. Presumably the compiler regards the value as already being of type "double", just one that happens to be stored in a longer register. -- Andrew (irc:RhodiumToad)
