It appears that decimal floating-point (DFP) constants and the operators "+" and "-" are done to type (as if DEC_EVAL_METHOD were 0), but that the operators "*" and "/" are done as if _Decimal128 (as if DEC_EVAL_METHOD were 2) -- this is in gcc 4.4.0. In gcc 4.3.2, everything was done as if to type (DEC_EVAL_METHOD were 0). This in on Intel Pentium 4 with Fedora Core Linux 11.
-- Summary: DEC_EVAL_METHOD not match operators Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tydeman at tybor dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40503