[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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 30fbed63c884ae04c1eee1134fb223d60210347f..8ce444b384797358ab6127e05d1415cdfd9b9b0d 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-11-23  James Greenhalgh  <james.greenhalgh@arm.com>
+
+       * common.opt (fpermitted-flt-eval-methods): New.
+       * doc/invoke.texi (-fpermitted-flt-eval-methods): Document it.
+       * flag_types.h (permitted_flt_eval_methods): New.
+
 2016-11-23  James Greenhalgh  <james.greenhalgh@arm.com>
 
        * config/m68k/m68k.c (m68k_excess_precision): New.

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 6b86dd2355f13ca3bf1895145f62330971602966..f4d81a19515aa7c024dd6ed88f660cd2c2be1f4d 100644 (file)
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2016-11-23  James Greenhalgh  <james.greenhalgh@arm.com>
+
+       * c-opts.c (c_common_post_options): Add logic to handle the default
+       case for -fpermitted-flt-eval-methods.
+
 2016-11-23  Paolo Bonzini  <bonzini@gnu.org>
 
        * c.opt (Wexpansion-to-defined): New.

diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index de260e7dcee8dc91cd251765cc893e764a6295a0..57717ff41d883bca9b5f14bf3ebd19653eac90f5 100644 (file)
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -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)

diff --git a/gcc/common.opt b/gcc/common.opt
index 1fa3629f54848d516a6b346d64172f1a6f5da92b..d7ccf3b1a90a1274b005ea916d510cbeda12fefd 100644 (file)
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -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
 

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 32c7a083be09cd3308e3ca37dc789a1fe237c510..a9d060999352d0e7e80b6e56778352cf972b929f 100644 (file)
--- 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

diff --git a/gcc/flag-types.h b/gcc/flag-types.h
index 6c5a4cc93461d9edb1605fac916541c4aa88fcf2..d69f8f489b82f4498cc0592af3f0468eea1e743e 100644 (file)
--- a/gcc/flag-types.h
+++ b/gcc/flag-types.h
@@ -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
 {

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d5055da891c7ea36df672e9e2744ad0be0898428..40d00326111858d34081fd03b76959d2a6e10a2f 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-11-23  James Greenhalgh  <james.greenhalgh@arm.com>
+
+       * gcc.dg/fpermitted-flt-eval-methods_1.c: New.
+       * gcc.dg/fpermitted-flt-eval-methods_2.c: New.
+
 2016-11-23  Martin Sebor  <msebor@redhat.com>
 
        PR middle-end/78461

diff --git a/gcc/testsuite/gcc.dg/fpermitted-flt-eval-methods_1.c b/gcc/testsuite/gcc.dg/fpermitted-flt-eval-methods_1.c
new file mode 100644 (file)
index 0000000..c022f86
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fpermitted-flt-eval-methods_1.c
@@ -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;
+    }
+}

diff --git a/gcc/testsuite/gcc.dg/fpermitted-flt-eval-methods_2.c b/gcc/testsuite/gcc.dg/fpermitted-flt-eval-methods_2.c
new file mode 100644 (file)
index 0000000..a76ea7e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fpermitted-flt-eval-methods_2.c
@@ -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;
+    }
+}