From: Richard Biener <rguenther@suse.de>
Date: Mon, 7 Nov 2016 12:26:00 +0000 (+0000)
Subject: re PR tree-optimization/78218 (wrong code at -Os and above on x86_64-linux-gnu (in... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=20770eb80bf59f4fe1d71408b841669c70550e6c;p=gcc.git

re PR tree-optimization/78218 (wrong code at -Os and above on x86_64-linux-gnu (in both 32-bit and 64-bit modes))

2016-11-07  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78218
	* gimple-ssa-store-merging.c
	(pass_store_merging::terminate_all_aliasing_chains):
	Drop unused argument, fix alias check to also consider uses.
	(pass_store_merging::execute): Adjust.

	* gcc.dg/torture/pr78218.c: New testcase.

From-SVN: r241900
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 262f0068b48..5ccd3b4ca62 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-11-07  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78218
+	* gimple-ssa-store-merging.c
+	(pass_store_merging::terminate_all_aliasing_chains):
+	Drop unused argument, fix alias check to also consider uses.
+	(pass_store_merging::execute): Adjust.
+
 2016-11-07  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/78228
diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c
index 36bc833af91..57b855671db 100644
--- a/gcc/gimple-ssa-store-merging.c
+++ b/gcc/gimple-ssa-store-merging.c
@@ -726,7 +726,7 @@ private:
   hash_map<tree_operand_hash, struct imm_store_chain_info *> m_stores;
 
   bool terminate_and_process_all_chains ();
-  bool terminate_all_aliasing_chains (tree, imm_store_chain_info **,
+  bool terminate_all_aliasing_chains (imm_store_chain_info **,
 				      bool, gimple *);
   bool terminate_and_release_chain (imm_store_chain_info *);
 }; // class pass_store_merging
@@ -755,8 +755,7 @@ pass_store_merging::terminate_and_process_all_chains ()
    If that is the case we have to terminate any chain anchored at BASE.  */
 
 bool
-pass_store_merging::terminate_all_aliasing_chains (tree dest,
-						   imm_store_chain_info
+pass_store_merging::terminate_all_aliasing_chains (imm_store_chain_info
 						     **chain_info,
 						   bool var_offset_p,
 						   gimple *stmt)
@@ -788,7 +787,10 @@ pass_store_merging::terminate_all_aliasing_chains (tree dest,
 	  unsigned int i;
 	  FOR_EACH_VEC_ELT ((*chain_info)->m_store_info, i, info)
 	    {
-	      if (stmt_may_clobber_ref_p (info->stmt, dest))
+	      if (ref_maybe_used_by_stmt_p (stmt,
+					    gimple_assign_lhs (info->stmt))
+		  || stmt_may_clobber_ref_p (stmt,
+					     gimple_assign_lhs (info->stmt)))
 		{
 		  if (dump_file && (dump_flags & TDF_DETAILS))
 		    {
@@ -1458,7 +1460,7 @@ pass_store_merging::execute (function *fun)
 		    }
 
 		  /* Store aliases any existing chain?  */
-		  terminate_all_aliasing_chains (lhs, chain_info, false, stmt);
+		  terminate_all_aliasing_chains (chain_info, false, stmt);
 		  /* Start a new chain.  */
 		  struct imm_store_chain_info *new_chain
 		    = new imm_store_chain_info (base_addr);
@@ -1477,13 +1479,13 @@ pass_store_merging::execute (function *fun)
 		    }
 		}
 	      else
-		terminate_all_aliasing_chains (lhs, chain_info,
+		terminate_all_aliasing_chains (chain_info,
 					       offset != NULL_TREE, stmt);
 
 	      continue;
 	    }
 
-	  terminate_all_aliasing_chains (NULL_TREE, NULL, false, stmt);
+	  terminate_all_aliasing_chains (NULL, false, stmt);
 	}
       terminate_and_process_all_chains ();
     }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0dff659bda4..242b51b3764 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-11-07  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78218
+	* gcc.dg/torture/pr78218.c: New testcase.
+
 2016-11-07  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/78228
diff --git a/gcc/testsuite/gcc.dg/torture/pr78218.c b/gcc/testsuite/gcc.dg/torture/pr78218.c
new file mode 100644
index 00000000000..b3e2892429d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr78218.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+
+struct 
+{
+  int v;
+} a[2];
+
+int b; 
+
+void __attribute__((noinline,noclone))
+check ()
+{
+  if (a[0].v != 1)
+    __builtin_abort ();
+}
+
+int main ()
+{
+  a[1].v = 1;
+  a[0] = a[1];
+  a[1].v = 0;
+  check (a);
+  return 0;
+}