[Patch 6/17] Migrate excess precision logic to use TARGET_EXCESS_PRECISION

gcc/

	* toplev.c (init_excess_precision): Delete most logic.
	* tree.c (excess_precision_type): Rewrite to use
	TARGET_EXCESS_PRECISION.
	* doc/invoke.texi (-fexcess-precision): Document behaviour in a
	more generic fashion.
	* ginclude/float.h: Wrap definition of FLT_EVAL_METHOD in
	__STDC_WANT_IEC_60559_TYPES_EXT__.

gcc/c-family/

	* c-common.c (excess_precision_mode_join): New.
	(c_ts18661_flt_eval_method): New.
	(c_c11_flt_eval_method): Likewise.
	(c_flt_eval_method): Likewise.
	* c-common.h (excess_precision_mode_join): New.
	(c_flt_eval_method): Likewise.
	* c-cppbuiltin.c (c_cpp_flt_eval_method_iec_559): New.
	(cpp_iec_559_value): Call it.
	(c_cpp_builtins): Modify logic for __LIBGCC_*_EXCESS_PRECISION__,
	call c_flt_eval_method to set __FLT_EVAL_METHOD__ and
	__FLT_EVAL_METHOD_TS_18661_3__.

gcc/testsuite/

	* gcc.dg/fpermitted-flt-eval-methods_3.c: New.
	* gcc.dg/fpermitted-flt-eval-methods_4.c: Likewise.

From-SVN: r242776

1 files changed, 6 insertions, 30 deletions

diff --git a/gcc/toplev.c b/gcc/toplev.c
index d43234a..5af02ea 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -1680,41 +1680,17 @@ backend_init (void)
   init_regs ();
 }
 
-/* Initialize excess precision settings.  */
+/* Initialize excess precision settings.
+
+   We have no need to modify anything here, just keep track of what the
+   user requested.  We'll figure out any appropriate relaxations
+   later.  */
+
 static void
 init_excess_precision (void)
 {
-  /* Adjust excess precision handling based on the target options.  If
-     the front end cannot handle it, flag_excess_precision_cmdline
-     will already have been set accordingly in the post_options
-     hook.  */
   gcc_assert (flag_excess_precision_cmdline != EXCESS_PRECISION_DEFAULT);
   flag_excess_precision = flag_excess_precision_cmdline;
-  if (flag_unsafe_math_optimizations)
-    flag_excess_precision = EXCESS_PRECISION_FAST;
-  if (flag_excess_precision == EXCESS_PRECISION_STANDARD)
-    {
-      int flt_eval_method = TARGET_FLT_EVAL_METHOD;
-      switch (flt_eval_method)
-	{
-	case -1:
-	case 0:
-	  /* Either the target acts unpredictably (-1) or has all the
-	     operations required not to have excess precision (0).  */
-	  flag_excess_precision = EXCESS_PRECISION_FAST;
-	  break;
-	case 1:
-	case 2:
-	  /* In these cases, predictable excess precision makes
-	     sense.  */
-	  break;
-	default:
-	  /* Any other implementation-defined FLT_EVAL_METHOD values
-	     require the compiler to handle the associated excess
-	     precision rules in excess_precision_type.  */
-	  gcc_unreachable ();
-	}
-    }
 }
 
 /* Initialize things that are both lang-dependent and target-dependent.