On Mon, 31 Jan 2022, Richard Biener via Gcc-patches wrote: > I wonder if it would make sense to handle it similar to > > inexact = real_arithmetic (&value, code, &d1, &d2); > real_convert (&result, mode, &value); > > /* Don't constant fold this floating point operation if > the result has overflowed and flag_trapping_math. */ > if (flag_trapping_math > && MODE_HAS_INFINITIES (mode) > && REAL_VALUE_ISINF (result) > && !REAL_VALUE_ISINF (d1) > && !REAL_VALUE_ISINF (d2)) > return NULL_TREE; > > thus whenever we fold to NaN but flag_trapping_math is set, > do not fold? We already exclude NaN operands earlier
Yes, it's true in general that a NaN result for non-NaN operands means "invalid" is raised. While an infinite result for finite operands means either "overflow" (if inexact) or "divide by zero" (if exact). (Underflow is more complicated.) -- Joseph S. Myers jos...@codesourcery.com
