2013-11-20 Richard Biener <rguenther@suse.de>

	PR lto/59035
	* lto-opts.c (lto_write_options): Write defaults only if
	they were not explicitely specified.  Also write
	-ffp-contract default.
	* lto-wrapper.c (merge_and_complain): Merge -ffp-contract
	conservatively.
	(run_gcc): Pass through -ffp-contract.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205096 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 46 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e36c825fb3b..2bd67d0ef49 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2013-11-20  Richard Biener  <rguenther@suse.de>
+
+	PR lto/59035
+	* lto-opts.c (lto_write_options): Write defaults only if
+	they were not explicitely specified.  Also write
+	-ffp-contract default.
+	* lto-wrapper.c (merge_and_complain): Merge -ffp-contract
+	conservatively.
+	(run_gcc): Pass through -ffp-contract.
+
 2013-11-20  Jan-Benedict Glaw  <jbglaw@lug-owl.de>
 
 	* config/mips/mips.c (r10k_simplify_address): Eliminate macro usage.
diff --git a/gcc/lto-opts.c b/gcc/lto-opts.c
index c9d4e03d00c..2cb536bfc55 100644
--- a/gcc/lto-opts.c
+++ b/gcc/lto-opts.c
@@ -85,14 +85,35 @@ lto_write_options (void)
      function rather than per compilation unit.  */
   /* -fexceptions causes the EH machinery to be initialized, enabling
      generation of unwind data so that explicit throw() calls work.  */
-  if (global_options.x_flag_exceptions)
+  if (!global_options_set.x_flag_exceptions
+      && global_options.x_flag_exceptions)
     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 				   "-fexceptions");
   /* -fnon-call-exceptions changes the generation of exception
       regions.  It is enabled implicitly by the Go frontend.  */
-  if (global_options.x_flag_non_call_exceptions)
+  if (!global_options_set.x_flag_non_call_exceptions
+      && global_options.x_flag_non_call_exceptions)
     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 				   "-fnon-call-exceptions");
+  /* The default -ffp-contract changes depending on the language
+     standard.  Pass thru conservative standard settings.  */
+  if (!global_options_set.x_flag_fp_contract_mode)
+    switch (global_options.x_flag_fp_contract_mode)
+      {
+      case FP_CONTRACT_OFF:
+	append_to_collect_gcc_options (&temporary_obstack, &first_p,
+				       "-ffp-contract=off");
+	break;
+      case FP_CONTRACT_ON:
+	append_to_collect_gcc_options (&temporary_obstack, &first_p,
+				       "-ffp-contract=on");
+	break;
+      case FP_CONTRACT_FAST:
+	/* Nothing.  That merges conservatively and is the default for LTO.  */
+	break;
+      default:
+	gcc_unreachable ();
+      }
 
   /* Output explicitly passed options.  */
   for (i = 1; i < save_decoded_options_count; ++i)
diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
index 57978c883d4..335ec8fd01a 100644
--- a/gcc/lto-wrapper.c
+++ b/gcc/lto-wrapper.c
@@ -422,6 +422,18 @@ merge_and_complain (struct cl_decoded_option **decoded_options,
 	    append_option (decoded_options, decoded_options_count, foption);
 	  break;
 
+	case OPT_ffp_contract_:
+	  /* For selected options we can merge conservatively.  */
+	  for (j = 0; j < *decoded_options_count; ++j)
+	    if ((*decoded_options)[j].opt_index == foption->opt_index)
+	      break;
+	  if (j == *decoded_options_count)
+	    append_option (decoded_options, decoded_options_count, foption);
+	  /* FP_CONTRACT_OFF < FP_CONTRACT_ON < FP_CONTRACT_FAST.  */
+	  else if (foption->value < (*decoded_options)[j].value)
+	    (*decoded_options)[j] = *foption;
+	  break;
+
 	case OPT_freg_struct_return:
 	case OPT_fpcc_struct_return:
 	  for (j = 0; j < *decoded_options_count; ++j)
@@ -578,6 +590,7 @@ run_gcc (unsigned argc, char *argv[])
 	case OPT_fgnu_tm:
 	case OPT_freg_struct_return:
 	case OPT_fpcc_struct_return:
+	case OPT_ffp_contract_:
 	  break;
 
 	default: