tree-ssa-sccvn.c (vn_reference_lookup_3): Handle arbitrary memset constants via…

tree-ssa-sccvn.c (vn_reference_lookup_3): Handle arbitrary memset constants via native_interpret_expr.

2018-05-23  Richard Biener  <rguenther@suse.de>

	* tree-ssa-sccvn.c (vn_reference_lookup_3): Handle arbitrary
	memset constants via native_interpret_expr.

	* gcc.dg/tree-ssa/ssa-fre-65.c: New testcase.

From-SVN: r260565

gcc/ChangeLog

+2018-05-23  Richard Biener  <rguenther@suse.de>
+
+	* tree-ssa-sccvn.c (vn_reference_lookup_3): Handle arbitrary
+	memset constants via native_interpret_expr.
+
 2018-05-22  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/85345

gcc/testsuite/ChangeLog

+2018-05-23  Richard Biener  <rguenther@suse.de>
+
+	* gcc.dg/tree-ssa/ssa-fre-65.c: New testcase.
+
 2018-05-22  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/85841

gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-65.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-fre1-details -fdump-tree-dse1-details" } */
+
+typedef unsigned char v16qi __attribute__((vector_size(16)));
+typedef unsigned short v8hi __attribute__((vector_size(16)));
+typedef unsigned int v4si __attribute__((vector_size(16)));
+void foo(char *dest)
+{
+  unsigned char x[256] __attribute__((aligned(16)));
+  __builtin_memset (x, 23, 256);
+  v16qi resqi = *(v16qi *)&x[16];
+  v8hi reshi = *(v8hi *)&x[16];
+  v4si ressi = *(v4si *)&x[16];
+  *(v16qi *)dest = resqi;
+  *(v8hi *)(dest + 16) = reshi;
+  *(v4si *)(dest + 32) = ressi;
+}
+
+/* { dg-final { scan-tree-dump-times "Replaced MEM" 3 "fre1" } } */
+/* { dg-final { scan-tree-dump-times "Deleted dead call" 1 "dse1" } } */

gcc/tree-ssa-sccvn.c

@@ -1959,9 +1959,9 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
   if (is_gimple_reg_type (vr->type)
       && gimple_call_builtin_p (def_stmt, BUILT_IN_MEMSET)
       && (integer_zerop (gimple_call_arg (def_stmt, 1))
-	  || (INTEGRAL_TYPE_P (vr->type)
+	  || ((TREE_CODE (gimple_call_arg (def_stmt, 1)) == INTEGER_CST
+	       || (INTEGRAL_TYPE_P (vr->type) && known_eq (ref->size, 8)))
 	      && CHAR_BIT == 8 && BITS_PER_UNIT == 8
-	      && known_eq (ref->size, 8)
 	      && known_eq (ref->size, maxsize)
 	      && offset.is_constant (&offseti)
 	      && offseti % BITS_PER_UNIT == 0))
@@ -2030,7 +2030,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
 	  tree val;
 	  if (integer_zerop (gimple_call_arg (def_stmt, 1)))
 	    val = build_zero_cst (vr->type);
-	  else
+	  else if (INTEGRAL_TYPE_P (vr->type)
+		   && known_eq (ref->size, 8))
 	    {
 	      code_helper rcode = NOP_EXPR;
 	      tree ops[3] = {};
@@ -2041,6 +2042,16 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
 		      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val)))
 		return (void *)-1;
 	    }
+	  else
+	    {
+	      unsigned len = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (vr->type));
+	      unsigned char *buf = XALLOCAVEC (unsigned char, len);
+	      memset (buf, TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 1)),
+		      len);
+	      val = native_interpret_expr (vr->type, buf, len);
+	      if (!val)
+		return (void *)-1;
+	    }
 	  return vn_reference_lookup_or_insert_for_pieces
 	           (vuse, vr->set, vr->type, vr->operands, val);
 	}