Index: gcc/common.opt
===================================================================
--- gcc/common.opt	(revision 276983)
+++ gcc/common.opt	(working copy)
@@ -993,6 +993,10 @@ Align the start of loops.
 falign-loops=
 Common RejectNegative Joined Var(str_align_loops) Optimization
 
+fallow-store-data-races
+Common Report Var(flag_store_data_races) Optimization
+Allow the compiler to introduce new data races on stores.
+
 fargument-alias
 Common Ignore
 Does nothing. Preserved for backward compatibility.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 276983)
+++ gcc/doc/invoke.texi	(working copy)
@@ -406,6 +406,7 @@ Objective-C and Objective-C++ Dialects}.
 -falign-jumps[=@var{n}[:@var{m}:[@var{n2}[:@var{m2}]]]] @gol
 -falign-labels[=@var{n}[:@var{m}:[@var{n2}[:@var{m2}]]]] @gol
 -falign-loops[=@var{n}[:@var{m}:[@var{n2}[:@var{m2}]]]] @gol
+-fallow-store-data-races @gol
 -fassociative-math  -fauto-profile  -fauto-profile[=@var{path}] @gol
 -fauto-inc-dec  -fbranch-probabilities @gol
 -fcaller-saves @gol
@@ -8463,9 +8464,9 @@ designed to reduce code size.
 Disregard strict standards compliance.  @option{-Ofast} enables all
 @option{-O3} optimizations.  It also enables optimizations that are not
 valid for all standard-compliant programs.
-It turns on @option{-ffast-math} and the Fortran-specific
-@option{-fstack-arrays}, unless @option{-fmax-stack-var-size} is
-specified, and @option{-fno-protect-parens}.
+It turns on @option{-ffast-math}, @option{-fallow-store-data-races}
+and the Fortran-specific @option{-fstack-arrays}, unless
+@option{-fmax-stack-var-size} is specified, and @option{-fno-protect-parens}.
 
 @item -Og
 @opindex Og
@@ -10227,6 +10228,12 @@ The maximum allowed @var{n} option value
 
 Enabled at levels @option{-O2}, @option{-O3}.
 
+@item -fallow-store-data-races
+@opindex fallow-store-data-races
+Allow the compiler to introduce new data races on stores.
+
+Enabled at level @option{-Ofast}.
+
 @item -funit-at-a-time
 @opindex funit-at-a-time
 This option is left for compatibility reasons. @option{-funit-at-a-time}
@@ -12060,10 +12067,6 @@ The maximum number of conditional store
 if either vectorization (@option{-ftree-vectorize}) or if-conversion
 (@option{-ftree-loop-if-convert}) is disabled.
 
-@item allow-store-data-races
-Allow optimizers to introduce new data races on stores.
-Set to 1 to allow, otherwise to 0.
-
 @item case-values-threshold
 The smallest number of different values for which it is best to use a
 jump-table instead of a tree of conditional branches.  If the value is
Index: gcc/opts.c
===================================================================
--- gcc/opts.c	(revision 276983)
+++ gcc/opts.c	(working copy)
@@ -564,6 +564,7 @@ static const struct default_options defa
 
     /* -Ofast adds optimizations to -O3.  */
     { OPT_LEVELS_FAST, OPT_ffast_math, NULL, 1 },
+    { OPT_LEVELS_FAST, OPT_fallow_store_data_races, NULL, 1 },
 
     { OPT_LEVELS_NONE, 0, NULL, 0 }
   };
@@ -671,13 +672,6 @@ default_options_optimization (struct gcc
      opt2 ? 100 : default_param_value (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE),
      opts->x_param_values, opts_set->x_param_values);
 
-  /* At -Ofast, allow store motion to introduce potential race conditions.  */
-  maybe_set_param_value
-    (PARAM_ALLOW_STORE_DATA_RACES,
-     opts->x_optimize_fast ? 1
-     : default_param_value (PARAM_ALLOW_STORE_DATA_RACES),
-     opts->x_param_values, opts_set->x_param_values);
-
   if (opts->x_optimize_size)
     /* We want to crossjump as much as possible.  */
     maybe_set_param_value (PARAM_MIN_CROSSJUMP_INSNS, 1,
Index: gcc/params.def
===================================================================
--- gcc/params.def	(revision 276983)
+++ gcc/params.def	(working copy)
@@ -1225,12 +1225,6 @@ DEFPARAM (PARAM_JUMP_TABLE_MAX_GROWTH_RA
 	  "optimizing for speed.",
 	  800, 0, 0)
 
-/* Data race flags for C++0x memory model compliance.  */
-DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
-	  "allow-store-data-races",
-	  "Allow new data races on stores to be introduced.",
-	  0, 0, 1)
-
 /* Reassociation width to be used by tree reassoc optimization.  */
 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
 	  "tree-reassoc-width",
Index: gcc/params.h
===================================================================
--- gcc/params.h	(revision 276983)
+++ gcc/params.h	(working copy)
@@ -228,8 +228,6 @@ extern void init_param_values (int *para
   PARAM_VALUE (PARAM_MAX_STORES_TO_SINK)
 #define ALLOW_LOAD_DATA_RACES \
   PARAM_VALUE (PARAM_ALLOW_LOAD_DATA_RACES)
-#define ALLOW_STORE_DATA_RACES \
-  PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES)
 #define ALLOW_PACKED_LOAD_DATA_RACES \
   PARAM_VALUE (PARAM_ALLOW_PACKED_LOAD_DATA_RACES)
 #define ALLOW_PACKED_STORE_DATA_RACES \
Index: gcc/testsuite/c-c++-common/cxxbitfields-3.c
===================================================================
--- gcc/testsuite/c-c++-common/cxxbitfields-3.c	(revision 276983)
+++ gcc/testsuite/c-c++-common/cxxbitfields-3.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do compile { target i?86-*-* x86_64-*-* } } */
-/* { dg-options "-O2 --param allow-store-data-races=0" } */
+/* { dg-options "-O2 -fno-allow-store-data-races" } */
 
 /* Make sure we don't narrow down to a QI or HI to store into VAR.J,
    but instead use an SI.  */
Index: gcc/testsuite/c-c++-common/cxxbitfields-6.c
===================================================================
--- gcc/testsuite/c-c++-common/cxxbitfields-6.c	(revision 276983)
+++ gcc/testsuite/c-c++-common/cxxbitfields-6.c	(working copy)
@@ -1,6 +1,6 @@
 /* PR middle-end/50141 */
 /* { dg-do compile } */
-/* { dg-options "-O2 --param allow-store-data-races=0" } */
+/* { dg-options "-O2 -fno-allow-store-data-races" } */
 
 struct S
 {
Index: gcc/testsuite/c-c++-common/simulate-thread/bitfields-1.c
===================================================================
--- gcc/testsuite/c-c++-common/simulate-thread/bitfields-1.c	(revision 276983)
+++ gcc/testsuite/c-c++-common/simulate-thread/bitfields-1.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/c-c++-common/simulate-thread/bitfields-2.c
===================================================================
--- gcc/testsuite/c-c++-common/simulate-thread/bitfields-2.c	(revision 276983)
+++ gcc/testsuite/c-c++-common/simulate-thread/bitfields-2.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link { target { ! int16 } } } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/c-c++-common/simulate-thread/bitfields-3.c
===================================================================
--- gcc/testsuite/c-c++-common/simulate-thread/bitfields-3.c	(revision 276983)
+++ gcc/testsuite/c-c++-common/simulate-thread/bitfields-3.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/c-c++-common/simulate-thread/bitfields-4.c
===================================================================
--- gcc/testsuite/c-c++-common/simulate-thread/bitfields-4.c	(revision 276983)
+++ gcc/testsuite/c-c++-common/simulate-thread/bitfields-4.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/g++.dg/simulate-thread/bitfields-2.C
===================================================================
--- gcc/testsuite/g++.dg/simulate-thread/bitfields-2.C	(revision 276983)
+++ gcc/testsuite/g++.dg/simulate-thread/bitfields-2.C	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 /* Test that setting <var.a> does not touch either <var.b> or <var.c>.
Index: gcc/testsuite/g++.dg/simulate-thread/bitfields.C
===================================================================
--- gcc/testsuite/g++.dg/simulate-thread/bitfields.C	(revision 276983)
+++ gcc/testsuite/g++.dg/simulate-thread/bitfields.C	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 /* Test that setting <var.a> does not touch either <var.b> or <var.c>.
Index: gcc/testsuite/gcc.dg/lto/pr52097_0.c
===================================================================
--- gcc/testsuite/gcc.dg/lto/pr52097_0.c	(revision 276983)
+++ gcc/testsuite/gcc.dg/lto/pr52097_0.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-lto-do link } */
-/* { dg-lto-options { { -O -flto -fexceptions -fnon-call-exceptions --param allow-store-data-races=0 } } } */
+/* { dg-lto-options { { -O -flto -fexceptions -fnon-call-exceptions -fno-allow-store-data-races } } } */
 /* { dg-require-effective-target exceptions } */
 
 typedef struct { unsigned int e0 : 16; } s1;
Index: gcc/testsuite/gcc.dg/simulate-thread/speculative-store-2.c
===================================================================
--- gcc/testsuite/gcc.dg/simulate-thread/speculative-store-2.c	(revision 276983)
+++ gcc/testsuite/gcc.dg/simulate-thread/speculative-store-2.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0 -O2" } */
+/* { dg-options "-fno-allow-store-data-races -O2" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/gcc.dg/simulate-thread/speculative-store-3.c
===================================================================
--- gcc/testsuite/gcc.dg/simulate-thread/speculative-store-3.c	(revision 276983)
+++ gcc/testsuite/gcc.dg/simulate-thread/speculative-store-3.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0 -O2" } */
+/* { dg-options "-fno-allow-store-data-races -O2" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/gcc.dg/simulate-thread/speculative-store-4.c
===================================================================
--- gcc/testsuite/gcc.dg/simulate-thread/speculative-store-4.c	(revision 276983)
+++ gcc/testsuite/gcc.dg/simulate-thread/speculative-store-4.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
Index: gcc/testsuite/gcc.dg/simulate-thread/speculative-store.c
===================================================================
--- gcc/testsuite/gcc.dg/simulate-thread/speculative-store.c	(revision 276983)
+++ gcc/testsuite/gcc.dg/simulate-thread/speculative-store.c	(working copy)
@@ -1,12 +1,12 @@
 /* { dg-do link } */
-/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-options "-fno-allow-store-data-races" } */
 /* { dg-final { simulate-thread } } */
 
 #include <stdio.h>
 #include "simulate-thread.h"
 
 /* This file tests that speculative store movement out of a loop doesn't 
-   happen.  This is disallowed when --param allow-store-data-races is 0.  */
+   happen.  This is disallowed when -fno-allow-store-data-races.  */
 
 int global = 100;
 
Index: gcc/testsuite/gcc.dg/tree-ssa/20050314-1.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/20050314-1.c	(revision 276983)
+++ gcc/testsuite/gcc.dg/tree-ssa/20050314-1.c	(working copy)
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O1 -fdump-tree-lim2-details --param allow-store-data-races=1" } */
+/* { dg-options "-O1 -fdump-tree-lim2-details -fallow-store-data-races" } */
 
 float a[100];
 
Index: gcc/tree-if-conv.c
===================================================================
--- gcc/tree-if-conv.c	(revision 276983)
+++ gcc/tree-if-conv.c	(working copy)
@@ -914,10 +914,10 @@ ifcvt_memrefs_wont_trap (gimple *stmt, v
          to unconditionally.  */
       if (base_master_dr
 	  && DR_BASE_W_UNCONDITIONALLY (*base_master_dr))
-	return PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES);
+	return flag_store_data_races;
       /* or the base is known to be not readonly.  */
       else if (base_object_writable (DR_REF (a)))
-	return PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES);
+	return flag_store_data_races;
     }
 
   return false;
Index: gcc/tree-ssa-loop-im.c
===================================================================
--- gcc/tree-ssa-loop-im.c	(revision 276983)
+++ gcc/tree-ssa-loop-im.c	(working copy)
@@ -2100,7 +2100,7 @@ execute_sm (class loop *loop, vec<edge>
   for_each_index (&ref->mem.ref, force_move_till, &fmt_data);
 
   if (bb_in_transaction (loop_preheader_edge (loop)->src)
-      || (! PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES)
+      || (! flag_store_data_races
 	  && ! ref_always_accessed_p (loop, ref, true)))
     multi_threaded_model_p = true;
 
