@@ -788,6 +788,18 @@ c_common_post_options (const char **pfilename)
&& flag_unsafe_math_optimizations == 0)
flag_fp_contract_mode = FP_CONTRACT_OFF;
+ /* If we are compiling C, and we are outside of a standards mode,
+ we can permit the new values from ISO/IEC TS 18661-3 for
+ FLT_EVAL_METHOD. Otherwise, we must restrict the possible values to
+ the set specified in ISO C99/C11. */
+ if (!flag_iso
+ && !c_dialect_cxx ()
+ && (global_options_set.x_flag_permitted_flt_eval_methods
+ == PERMITTED_FLT_EVAL_METHODS_DEFAULT))
+ flag_permitted_flt_eval_methods = PERMITTED_FLT_EVAL_METHODS_TS_18661;
+ else
+ flag_permitted_flt_eval_methods = PERMITTED_FLT_EVAL_METHODS_C11;
+
/* By default we use C99 inline semantics in GNU99 or C99 mode. C99
inline semantics are not supported in GNU89 or C89 mode. */
if (flag_gnu89_inline == -1)
@@ -1326,6 +1326,21 @@ Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
EnumValue
Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
+; Whether we permit the extended set of values for FLT_EVAL_METHOD
+; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
+fpermitted-flt-eval-methods=
+Common Joined RejectNegative Enum(permitted_flt_eval_methods) Var(flag_permitted_flt_eval_methods) Init(PERMITTED_FLT_EVAL_METHODS_DEFAULT)
+-fpermitted-flt-eval-methods=[c11|ts-18661] Specify which values of FLT_EVAL_METHOD are permitted.
+
+Enum
+Name(permitted_flt_eval_methods) Type(enum permitted_flt_eval_methods) UnknownError(unknown specification for the set of FLT_EVAL_METHOD values to permit %qs)
+
+EnumValue
+Enum(permitted_flt_eval_methods) String(c11) Value(PERMITTED_FLT_EVAL_METHODS_C11)
+
+EnumValue
+Enum(permitted_flt_eval_methods) String(ts-18661-3) Value(PERMITTED_FLT_EVAL_METHODS_TS_18661)
+
ffast-math
Common Optimization
@@ -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} @gol
-fhosted -ffreestanding -fopenacc -fopenmp -fopenmp-simd @gol
@@ -1872,6 +1873,30 @@ 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
@@ -158,6 +158,14 @@ enum excess_precision
EXCESS_PRECISION_STANDARD
};
+/* The options for which values of FLT_EVAL_METHOD are permissible. */
+enum permitted_flt_eval_methods
+{
+ PERMITTED_FLT_EVAL_METHODS_DEFAULT,
+ PERMITTED_FLT_EVAL_METHODS_TS_18661,
+ PERMITTED_FLT_EVAL_METHODS_C11
+};
+
/* Type of stack check. */
enum stack_check_type
{
new file mode 100644
@@ -0,0 +1,19 @@
+/* { dg-do run } */
+/* { dg-options "-std=c11" } */
+
+/* Test that we only see the C99/C11 values for __FLT_EVAL_METHOD__ if
+ we are compiling with -std=c11. */
+
+int main (int argc, char** argv)
+{
+ switch (__FLT_EVAL_METHOD__)
+ {
+ case 0:
+ case 1:
+ case 2:
+ case -1:
+ return 0;
+ default:
+ return 1;
+ }
+}
new file mode 100644
@@ -0,0 +1,19 @@
+/* { dg-do run } */
+/* { dg-options "-fpermitted-flt-eval-methods=c11" } */
+
+/* Test that we only see the C99/C11 values for __FLT_EVAL_METHOD__ if
+ we are compiling with -fpermitted-flt-eval-methods=c11. */
+
+int main (int argc, char** argv)
+{
+ switch (__FLT_EVAL_METHOD__)
+ {
+ case 0:
+ case 1:
+ case 2:
+ case -1:
+ return 0;
+ default:
+ return 1;
+ }
+}