https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107608
--- Comment #43 from rguenther at suse dot de <rguenther at suse dot de> --- On Thu, 19 Jan 2023, xry111 at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107608 > > --- Comment #42 from Xi Ruoyao <xry111 at gcc dot gnu.org> --- > (In reply to Richard Biener from comment #41) > > We could fix the testcase with > > > > diff --git a/gcc/testsuite/gcc.dg/pr95115.c b/gcc/testsuite/gcc.dg/pr95115.c > > index 69c4f83250c..09273e445d2 100644 > > --- a/gcc/testsuite/gcc.dg/pr95115.c > > +++ b/gcc/testsuite/gcc.dg/pr95115.c > > @@ -17,6 +17,7 @@ int > > main (void) > > { > > double r = x (); > > + volatile double rr = r; > > if (!__builtin_isnan (r)) > > abort (); > > if (!fetestexcept (FE_INVALID)) > > > > that preserves optimizing the isnan check but also preserves the computation > > and checks the non-propagation of a NaN. > > Hmm, so it means we cannot rely on Inf / Inf to raise an exception? Then we > need to fix Glibc... If the result is unused then no, GCC will happily elide exceptions from unused computations like Inexact from the statement 1./3.; but this has been done before. What's new is that GCC can now elide some uses (in this case the isnan check is the only use)
