re PR tree-optimization/51987 (Predictive commoning wrong-code with non-volatile asm)

	PR tree-optimization/51987
	* tree-data-ref.c (get_references_in_stmt): Handle references in
	non-volatile GIMPLE_ASM.

	* gcc.target/i386/pr51987.c: New test.

From-SVN: r183524

gcc/ChangeLog

+2012-01-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/51987
+	* tree-data-ref.c (get_references_in_stmt): Handle references in
+	non-volatile GIMPLE_ASM.
+
 2012-01-25  Richard Guenther  <rguenther@suse.de>
 
 	* tree-ssa-sccvn.c (vn_reference_eq): Also compare if both

gcc/testsuite/ChangeLog

+2012-01-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/51987
+	* gcc.target/i386/pr51987.c: New test.
+
 2012-01-25  Greta Yorsh  <Greta.Yorsh@arm.com>
 
 	* gcc.dg/tm/lto-1.c: Require lto support in target.

gcc/testsuite/gcc.target/i386/pr51987.c

+/* PR tree-optimization/51987 */
+/* { dg-do run { target { ! { ia32 } } } } */
+/* { dg-options "-O3" } */
+
+extern void abort (void);
+union U { unsigned long long l; struct { unsigned int l, h; } i; };
+
+__attribute__((noinline, noclone)) void
+foo (char *x, char *y)
+{
+  int i;
+  for (i = 0; i < 64; i++)
+    {
+      union U u;
+      asm ("movl %1, %k0; salq $32, %0" : "=r" (u.l) : "r" (i));
+      x[i] = u.i.h;
+      union U v;
+      asm ("movl %1, %k0; salq $32, %0" : "=r" (v.l) : "r" (i));
+      y[i] = v.i.h;
+    }
+}
+
+int
+main ()
+{
+  char a[64], b[64];
+  int i;
+  foo (a, b);
+  for (i = 0; i < 64; i++)
+    if (a[i] != i || b[i] != i)
+      abort ();
+  return 0;
+}

gcc/tree-data-ref.c

 /* Data references and dependences detectors.
-   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
    Free Software Foundation, Inc.
    Contributed by Sebastian Pop <pop@cri.ensmp.fr>
 
@@ -4185,7 +4185,7 @@ get_references_in_stmt (gimple stmt, VEC (data_ref_loc, heap) **references)
   if ((stmt_code == GIMPLE_CALL
        && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
       || (stmt_code == GIMPLE_ASM
-	  && gimple_asm_volatile_p (stmt)))
+	  && (gimple_asm_volatile_p (stmt) || gimple_vuse (stmt))))
     clobbers_memory = true;
 
   if (!gimple_vuse (stmt))