static const double coeff[] = { +854513.0l /138 };
compiles as C almost everywhere, except ppc* with -mlong-double-128
-mabi=ibmlongdouble.
const_binop refuses to compute this:
/* Don't constant fold this floating point operation if the
result may dependent upon the run-time rounding mode and
flag_rounding_math is set, or if GCC's software emulation
is unable to accurately represent the result. */
if ((flag_rounding_math
|| (REAL_MODE_FORMAT_COMPOSITE_P (mode)
&& !flag_unsafe_math_optimizations))
&& (inexact || !real_identical (&result, &value)))
return NULL_TREE;
Now, is the above valid ISO C99? I couldn't find anything that would say this
is not a valid constant expression, certainly it fits into double's range.
Perhaps we should differentiate here if we are evaluating an initializer or
not.
--
Summary: C constant expressions vs. IBM extended format long
double
Product: gcc
Version: 4.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jakub at gcc dot gnu dot org
GCC target triplet: powerpc*-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27054
