tree-optimization/93508 - make VN translate through _chk and valueize length

Value-numbering failed to handle __builtin_{memcpy,memset,...}_chk
variants when removing abstraction and also failed to use the
value-numbering lattice when requiring the length argument of the
call to be constant.

2020-02-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/93508
	* tree-ssa-sccvn.c (vn_reference_lookup_3): Handle _CHK like
	non-_CHK variants.  Valueize their length arguments.

	* gcc.dg/tree-ssa/ssa-fre-85.c: New testcase.

gcc/ChangeLog

 2020-02-27  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/93508
+	* tree-ssa-sccvn.c (vn_reference_lookup_3): Handle _CHK like
+	non-_CHK variants.  Valueize their length arguments.
+
+2020-02-27  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/93953
 	* tree-vect-slp.c (slp_copy_subtree): Avoid keeping a reference
 	to the hash-map entry.

gcc/testsuite/ChangeLog

 2020-02-27  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/93508
+	* gcc.dg/tree-ssa/ssa-fre-85.c: New testcase.
+
+2020-02-27  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/93953
 	* gcc.dg/pr93953.c: New testcase.
 

gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-87.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-fre1" } */
+
+unsigned int foo(unsigned int x, int *p)
+{
+  unsigned int src = x;
+  unsigned int dst;
+  *p = sizeof (unsigned int);
+  __builtin___memcpy_chk (&dst, &src, *p, 16);
+  return dst;
+}
+
+/* { dg-final { scan-tree-dump "return x" "fre1" } } */

gcc/tree-ssa-sccvn.c

@@ -2537,7 +2537,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
      from that definition.
      1) Memset.  */
   if (is_gimple_reg_type (vr->type)
-      && gimple_call_builtin_p (def_stmt, BUILT_IN_MEMSET)
+      && (gimple_call_builtin_p (def_stmt, BUILT_IN_MEMSET)
+	  || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMSET_CHK))
       && (integer_zerop (gimple_call_arg (def_stmt, 1))
 	  || ((TREE_CODE (gimple_call_arg (def_stmt, 1)) == INTEGER_CST
 	       || (INTEGRAL_TYPE_P (vr->type) && known_eq (ref->size, 8)))
@@ -2548,7 +2549,9 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	      && ref->size.is_constant (&sizei)
 	      && (offseti % BITS_PER_UNIT == 0
 		  || TREE_CODE (gimple_call_arg (def_stmt, 1)) == INTEGER_CST)))
-      && poly_int_tree_p (gimple_call_arg (def_stmt, 2))
+      && (poly_int_tree_p (gimple_call_arg (def_stmt, 2))
+	  || (TREE_CODE (gimple_call_arg (def_stmt, 2)) == SSA_NAME
+	      && poly_int_tree_p (SSA_VAL (gimple_call_arg (def_stmt, 2)))))
       && (TREE_CODE (gimple_call_arg (def_stmt, 0)) == ADDR_EXPR
 	  || TREE_CODE (gimple_call_arg (def_stmt, 0)) == SSA_NAME))
     {
@@ -2609,6 +2612,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	return (void *)-1;
       tree len = gimple_call_arg (def_stmt, 2);
       HOST_WIDE_INT leni, offset2i;
+      if (TREE_CODE (len) == SSA_NAME)
+	len = SSA_VAL (len);
       /* Sometimes the above trickery is smarter than alias analysis.  Take
          advantage of that.  */
       if (!ranges_maybe_overlap_p (offset, maxsize, offset2,
@@ -3149,13 +3154,19 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	   && is_gimple_reg_type (vr->type)
 	   /* ???  Handle BCOPY as well.  */
 	   && (gimple_call_builtin_p (def_stmt, BUILT_IN_MEMCPY)
+	       || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMCPY_CHK)
 	       || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMPCPY)
-	       || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMMOVE))
+	       || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMPCPY_CHK)
+	       || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMMOVE)
+	       || gimple_call_builtin_p (def_stmt, BUILT_IN_MEMMOVE_CHK))
 	   && (TREE_CODE (gimple_call_arg (def_stmt, 0)) == ADDR_EXPR
 	       || TREE_CODE (gimple_call_arg (def_stmt, 0)) == SSA_NAME)
 	   && (TREE_CODE (gimple_call_arg (def_stmt, 1)) == ADDR_EXPR
 	       || TREE_CODE (gimple_call_arg (def_stmt, 1)) == SSA_NAME)
-	   && poly_int_tree_p (gimple_call_arg (def_stmt, 2), &copy_size)
+	   && (poly_int_tree_p (gimple_call_arg (def_stmt, 2), &copy_size)
+	       || (TREE_CODE (gimple_call_arg (def_stmt, 2)) == SSA_NAME
+		   && poly_int_tree_p (SSA_VAL (gimple_call_arg (def_stmt, 2)),
+				       &copy_size)))
 	   /* Handling this is more complicated, give up for now.  */
 	   && data->partial_defs.is_empty ())
     {