[Patch 5/17] Add -fpermitted-flt-eval-methods=[c11|ts-18661-3]

gcc/c-family/

	* c-opts.c (c_common_post_options): Add logic to handle the default
	case for -fpermitted-flt-eval-methods.

gcc/

	* common.opt (fpermitted-flt-eval-methods): New.
	* doc/invoke.texi (-fpermitted-flt-eval-methods): Document it.
	* flag_types.h (permitted_flt_eval_methods): New.

gcc/testsuite/

	* gcc.dg/fpermitted-flt-eval-methods_1.c: New.
	* gcc.dg/fpermitted-flt-eval-methods_2.c: New.

From-SVN: r242775

1 files changed, 25 insertions, 0 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 32c7a08..a9d0609 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -178,6 +178,7 @@ in the following sections.
 @item C Language Options
 @xref{C Dialect Options,,Options Controlling C Dialect}.
 @gccoptlist{-ansi  -std=@var{standard}  -fgnu89-inline @gol
+-fpermitted-flt-eval-methods=@var{standard} @gol
 -aux-info @var{filename} -fallow-parameterless-variadic-functions @gol
 -fno-asm  -fno-builtin  -fno-builtin-@var{function} -fgimple@gol
 -fhosted  -ffreestanding -fopenacc -fopenmp -fopenmp-simd @gol
@@ -1867,6 +1868,30 @@ The preprocessor macros @code{__GNUC_GNU_INLINE__} and
 in effect for @code{inline} functions.  @xref{Common Predefined
 Macros,,,cpp,The C Preprocessor}.
 
+@item -fpermitted-flt-eval-methods=@var{style}
+@opindex fpermitted-flt-eval-methods
+@opindex fpermitted-flt-eval-methods=c11
+@opindex fpermitted-flt-eval-methods=ts-18661-3
+ISO/IEC TS 18661-3 defines new permissible values for
+@code{FLT_EVAL_METHOD} that indicate that operations and constants with
+a semantic type that is an interchange or extended format should be
+evaluated to the precision and range of that type.  These new values are
+a superset of those permitted under C99/C11, which does not specify the
+meaning of other positive values of @code{FLT_EVAL_METHOD}.  As such, code
+conforming to C11 may not have been written expecting the possibility of
+the new values.
+
+@option{-fpermitted-flt-eval-methods} specifies whether the compiler
+should allow only the values of @code{FLT_EVAL_METHOD} specified in C99/C11,
+or the extended set of values specified in ISO/IEC TS 18661-3.
+
+@var{style} is either @code{c11} or @code{ts-18661-3} as appropriate.
+
+The default when in a standards compliant mode (@option{-std=c11} or similar)
+is @option{-fpermitted-flt-eval-methods=c11}.  The default when in a GNU
+dialect (@option{-std=gnu11} or similar) is
+@option{-fpermitted-flt-eval-methods=ts-18661-3}.
+
 @item -aux-info @var{filename}
 @opindex aux-info
 Output to the given filename prototyped declarations for all functions