diff options
Diffstat (limited to 'src/backend/utils/adt/float.c')
| -rw-r--r-- | src/backend/utils/adt/float.c | 43 |
1 files changed, 33 insertions, 10 deletions
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c index 6a717f19bba..84d37de9304 100644 --- a/src/backend/utils/adt/float.c +++ b/src/backend/utils/adt/float.c @@ -1565,7 +1565,7 @@ dpow(PG_FUNCTION_ARGS) if (unlikely(isinf(result)) && !isinf(arg1) && !isinf(arg2)) float_overflow_error(); - if (unlikely(result == 0.0) && arg1 != 0.0) + if (unlikely(result == 0.0) && arg1 != 0.0 && !isinf(arg1) && !isinf(arg2)) float_underflow_error(); PG_RETURN_FLOAT8(result); @@ -1581,15 +1581,38 @@ dexp(PG_FUNCTION_ARGS) float8 arg1 = PG_GETARG_FLOAT8(0); float8 result; - errno = 0; - result = exp(arg1); - if (errno == ERANGE && result != 0 && !isinf(result)) - result = get_float8_infinity(); - - if (unlikely(isinf(result)) && !isinf(arg1)) - float_overflow_error(); - if (unlikely(result == 0.0)) - float_underflow_error(); + /* + * Handle NaN and Inf cases explicitly. This avoids needing to assume + * that the platform's exp() conforms to POSIX for these cases, and it + * removes some edge cases for the overflow checks below. + */ + if (isnan(arg1)) + result = arg1; + else if (isinf(arg1)) + { + /* Per POSIX, exp(-Inf) is 0 */ + result = (arg1 > 0.0) ? arg1 : 0; + } + else + { + /* + * On some platforms, exp() will not set errno but just return Inf or + * zero to report overflow/underflow; therefore, test both cases. + */ + errno = 0; + result = exp(arg1); + if (unlikely(errno == ERANGE)) + { + if (result != 0.0) + float_overflow_error(); + else + float_underflow_error(); + } + else if (unlikely(isinf(result))) + float_overflow_error(); + else if (unlikely(result == 0.0)) + float_underflow_error(); + } PG_RETURN_FLOAT8(result); } |