diff options
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/invoke.texi | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index c6de620..1c0fe7d 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -13747,18 +13747,18 @@ default, @option{-fexcess-precision=fast} is in effect; this means that operations may be carried out in a wider precision than the types specified in the source if that would result in faster code, and it is unpredictable when rounding to the types specified in the source code takes place. -When compiling C, if @option{-fexcess-precision=standard} is specified then -excess precision follows the rules specified in ISO C99; in particular, +When compiling C or C++, if @option{-fexcess-precision=standard} is specified +then excess precision follows the rules specified in ISO C99 or C++; in particular, both casts and assignments cause values to be rounded to their semantic types (whereas @option{-ffloat-store} only affects -assignments). This option is enabled by default for C if a strict -conformance option such as @option{-std=c99} is used. +assignments). This option is enabled by default for C or C++ if a strict +conformance option such as @option{-std=c99} or @option{-std=c++17} is used. @option{-ffast-math} enables @option{-fexcess-precision=fast} by default regardless of whether a strict conformance option is used. @opindex mfpmath @option{-fexcess-precision=standard} is not implemented for languages -other than C. On the x86, it has no effect if @option{-mfpmath=sse} +other than C or C++. On the x86, it has no effect if @option{-mfpmath=sse} or @option{-mfpmath=sse+387} is specified; in the former case, IEEE semantics apply without excess precision, and in the latter, rounding is unpredictable. |