re PR tree-optimization/57275 (Error in data dependence analysis during gather vectorization)

2013-05-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/57275
	* tree-vect-data-refs.c (vect_analyze_data_ref_dependence): Fix
	return value for fail to do runtime alias checks for gather loads.

	* gcc.target/i386/pr57275.c: New testcase.

From-SVN: r198918

gcc/ChangeLog

+2013-05-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/57275
+	* tree-vect-data-refs.c (vect_analyze_data_ref_dependence): Fix
+	return value for fail to do runtime alias checks for gather loads.
+
 2013-05-15  Jan Hubicka  <jh@suse.cz>
 
 	PR lto/57038

gcc/testsuite/ChangeLog

+2013-05-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/57275
+	* gcc.target/i386/pr57275.c: New testcase.
+
 2013-05-15  Jan Hubicka  <jh@suse.cz>
 
 	* gcc.dg/lto/attr-weakref-1_0.c: New testcase.

gcc/testsuite/gcc.target/i386/pr57275.c

+/* { dg-do run } */
+/* { dg-options "-O3 -march=native" } */
+
+extern void abort (void);
+
+#define N 1024
+
+float a[N], b[N], c[N];
+int k[N];
+
+__attribute__((noinline, noclone)) void
+f (void)
+{
+  int i;
+  for (i = 0; i < N; i++)
+    {
+      a[i] = b[k[i]];
+      b[i] = c[i];
+    }
+}
+
+int main ()
+{
+  int i;
+
+  for (i = 0; i < N; i++)
+  {
+    k[i] = i%2;
+    b[i] = i;
+    c[i] = 179;
+  }
+
+  f ();
+
+  if (a[2] != 179 || a[3] != 179)
+    abort ();
+
+  return 0;
+}

gcc/tree-vect-data-refs.c

@@ -269,7 +269,7 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
 	      dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM,
 				 DR_REF (drb));
 	    }
-	  return false;
+	  return true;
 	}
 
       if (dump_enabled_p ())
@@ -305,7 +305,7 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
 	      dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM,
 				 DR_REF (drb));
 	    }
-	  return false;
+	  return true;
 	}
 
       if (dump_enabled_p ())