common.opt (ftree-loop-if-convert-stores): Mark as preserved for backward compatibility.

2016-11-17  Richard Biener  <rguenther@suse.de>

	* common.opt (ftree-loop-if-convert-stores): Mark as preserved for
	backward compatibility.
	* doc/invoke.texi (ftree-loop-if-convert-stores): Remove.
	* tree-if-conv.c (pass_if_conversion::gate): Do not test
	flag_tree_loop_if_convert_stores.
	(pass_if_conversion::execute): Likewise.

From-SVN: r242542

4 files changed, 13 insertions, 24 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1050391b8ef..e07caaa2623 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2016-11-17  Richard Biener  <rguenther@suse.de>
+
+	* common.opt (ftree-loop-if-convert-stores): Mark as preserved for
+	backward compatibility.
+	* doc/invoke.texi (ftree-loop-if-convert-stores): Remove.
+	* tree-if-conv.c (pass_if_conversion::gate): Do not test
+	flag_tree_loop_if_convert_stores.
+	(pass_if_conversion::execute): Likewise.
+
 2016-11-17  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/aarch64/predicates.md (aarch64_reg_or_fp_zero): Check for
diff --git a/gcc/common.opt b/gcc/common.opt
index 5e8d72d6ae6..1fa3629f548 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1526,8 +1526,8 @@ Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
 Convert conditional jumps in innermost loops to branchless equivalents.
 
 ftree-loop-if-convert-stores
-Common Report Var(flag_tree_loop_if_convert_stores) Optimization
-Also if-convert conditional jumps containing memory writes.
+Common Ignore
+Does nothing. Preserved for backward compatibility.
 
 ; -finhibit-size-directive inhibits output of .size for ELF.
 ; This is used only for compiling crtstuff.c,
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 620225c37cf..e6c3dc267cf 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -412,7 +412,7 @@ Objective-C and Objective-C++ Dialects}.
 -ftree-builtin-call-dce -ftree-ccp -ftree-ch @gol
 -ftree-coalesce-vars -ftree-copy-prop -ftree-dce -ftree-dominator-opts @gol
 -ftree-dse -ftree-forwprop -ftree-fre -fcode-hoisting -ftree-loop-if-convert @gol
--ftree-loop-if-convert-stores -ftree-loop-im @gol
+-ftree-loop-im @gol
 -ftree-phiprop -ftree-loop-distribution -ftree-loop-distribute-patterns @gol
 -ftree-loop-ivcanon -ftree-loop-linear -ftree-loop-optimize @gol
 -ftree-loop-vectorize @gol
@@ -8061,24 +8061,6 @@ the innermost loops in order to improve the ability of the
 vectorization pass to handle these loops.  This is enabled by default
 if vectorization is enabled.
 
-@item -ftree-loop-if-convert-stores
-@opindex ftree-loop-if-convert-stores
-Attempt to also if-convert conditional jumps containing memory writes.
-This transformation can be unsafe for multi-threaded programs as it
-transforms conditional memory writes into unconditional memory writes.
-For example,
-@smallexample
-for (i = 0; i < N; i++)
-  if (cond)
-    A[i] = expr;
-@end smallexample
-is transformed to
-@smallexample
-for (i = 0; i < N; i++)
-  A[i] = cond ? expr : A[i];
-@end smallexample
-potentially producing data races.
-
 @item -ftree-loop-distribution
 @opindex ftree-loop-distribution
 Perform loop distribution.  This flag can improve cache performance on
diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 46d6b342328..dc97fc498df 100644
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -2872,8 +2872,7 @@ pass_if_conversion::gate (function *fun)
 {
   return (((flag_tree_loop_vectorize || fun->has_force_vectorize_loops)
 	   && flag_tree_loop_if_convert != 0)
-	  || flag_tree_loop_if_convert == 1
-	  || flag_tree_loop_if_convert_stores == 1);
+	  || flag_tree_loop_if_convert == 1);
 }
 
 unsigned int
@@ -2887,7 +2886,6 @@ pass_if_conversion::execute (function *fun)
 
   FOR_EACH_LOOP (loop, 0)
     if (flag_tree_loop_if_convert == 1
-	|| flag_tree_loop_if_convert_stores == 1
 	|| ((flag_tree_loop_vectorize || loop->force_vectorize)
 	    && !loop->dont_vectorize))
       todo |= tree_if_conversion (loop);