From: Bernd Schmidt <bernds@redhat.com>
Date: Fri, 27 Nov 2015 10:05:36 +0000 (+0000)
Subject: Be more careful about barriers when speculating conditional stores.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c000cd7c93aa657aae1cdfd6ce9b950b78c79624;p=gcc.git

Be more careful about barriers when speculating conditional stores.

	* gimple.h (nonbarrier_call_p): Declare.
	* gimple.c (nonbarrier_call_p): New function.
	* tree-ssa-phiopt.c (nontrapping_dom_walker::before_dom_children):
	Also increment call phase for ASMs with vdef and potential barrier
	calls.

From-SVN: r231005
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4510240eb22..e9fbabf6671 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2015-11-27  Bernd Schmidt  <bschmidt@redhat.com>
+
+	* gimple.h (nonbarrier_call_p): Declare.
+	* gimple.c (nonbarrier_call_p): New function.
+	* tree-ssa-phiopt.c (nontrapping_dom_walker::before_dom_children):
+	Also increment call phase for ASMs with vdef and potential barrier
+	calls.
+
 2015-11-27  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* ifcvt.c (insn_valid_noce_process_p): Reject insn if it satisfies
diff --git a/gcc/gimple.c b/gcc/gimple.c
index 2764df88186..bf552a7ae9c 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -2636,6 +2636,18 @@ nonfreeing_call_p (gimple *call)
   return n->nonfreeing_fn;
 }
 
+/* Return true when CALL is a call stmt that definitely need not
+   be considered to be a memory barrier.  */
+bool
+nonbarrier_call_p (gimple *call)
+{
+  if (gimple_call_flags (call) & (ECF_PURE | ECF_CONST))
+    return true;
+  /* Should extend this to have a nonbarrier_fn flag, just as above in
+     the nonfreeing case.  */
+  return false;
+}
+
 /* Callback for walk_stmt_load_store_ops.
  
    Return TRUE if OP will dereference the tree stored in DATA, FALSE
diff --git a/gcc/gimple.h b/gcc/gimple.h
index 6eb22de1e5e..0b04804ce46 100644
--- a/gcc/gimple.h
+++ b/gcc/gimple.h
@@ -1507,6 +1507,7 @@ extern bool gimple_call_builtin_p (const gimple *, enum built_in_function);
 extern bool gimple_asm_clobbers_memory_p (const gasm *);
 extern void dump_decl_set (FILE *, bitmap);
 extern bool nonfreeing_call_p (gimple *);
+extern bool nonbarrier_call_p (gimple *);
 extern bool infer_nonnull_range (gimple *, tree);
 extern bool infer_nonnull_range_by_dereference (gimple *, tree);
 extern bool infer_nonnull_range_by_attribute (gimple *, tree);
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 02d5aa010c3..344cd2f2701 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1519,7 +1519,9 @@ nontrapping_dom_walker::before_dom_children (basic_block bb)
     {
       gimple *stmt = gsi_stmt (gsi);
 
-      if (is_gimple_call (stmt) && !nonfreeing_call_p (stmt))
+      if ((gimple_code (stmt) == GIMPLE_ASM && gimple_vdef (stmt))
+	  || (is_gimple_call (stmt)
+	      && (!nonfreeing_call_p (stmt) || !nonbarrier_call_p (stmt))))
 	nt_call_phase++;
       else if (gimple_assign_single_p (stmt) && !gimple_has_volatile_ops (stmt))
 	{