re PR tree-optimization/58483 (missing optimization opportunity for const…

re PR tree-optimization/58483 (missing optimization opportunity for const std::vector compared to std::array)

2019-07-02  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/58483
	* tree-ssa-scopedtables.c (avail_expr_hash): Use OEP_ADDRESS_OF
	for MEM_REF base hashing.
	(equal_mem_array_ref_p): Likewise for base comparison.

	* gcc.dg/tree-ssa/ssa-dom-cse-8.c: New testcase.

From-SVN: r272922

gcc/ChangeLog

+2019-07-02  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/58483
+	* tree-ssa-scopedtables.c (avail_expr_hash): Use OEP_ADDRESS_OF
+	for MEM_REF base hashing.
+	(equal_mem_array_ref_p): Likewise for base comparison.
+
 2019-07-01  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	* config/rs6000/rs6000.md (signbit<mode>2_dm): Make this a

gcc/testsuite/ChangeLog

+2019-07-02  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/58483
+	* gcc.dg/tree-ssa/ssa-dom-cse-8.c: New testcase.
+
 2019-07-01  Andreas Krebbel  <krebbel@linux.ibm.com>
 
 	* gcc.target/s390/vector/vec-shift-2.c: New test.

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-cse-8.c

+/* { dg-do compile } */
+/* { dg-options "-O -fgimple -fdump-tree-dom2" } */
+
+int __GIMPLE (ssa,startwith("dom"))
+foo (void *p)
+{
+  int _2;
+
+  __BB(2):
+  __MEM <int> ((char *)p_1(D) + 4) = 20;
+  _2 = __MEM <const int> ((int *)p_1(D) + 4);
+  return _2;
+}
+
+/* { dg-final { scan-tree-dump "return 20;" "dom2" } } */

gcc/tree-ssa-scopedtables.c

@@ -494,7 +494,9 @@ avail_expr_hash (class expr_hash_elt *p)
 	    {
 	      enum tree_code code = MEM_REF;
 	      hstate.add_object (code);
-	      inchash::add_expr (base, hstate);
+	      inchash::add_expr (base, hstate,
+				 TREE_CODE (base) == MEM_REF 
+				 ? OEP_ADDRESS_OF : 0);
 	      hstate.add_object (offset);
 	      hstate.add_object (size);
 	      return hstate.end ();
@@ -540,7 +542,12 @@ equal_mem_array_ref_p (tree t0, tree t1)
   if (rev0 != rev1 || maybe_ne (sz0, sz1) || maybe_ne (off0, off1))
     return false;
 
-  return operand_equal_p (base0, base1, 0);
+  return operand_equal_p (base0, base1,
+			  (TREE_CODE (base0) == MEM_REF
+			   || TREE_CODE (base0) == TARGET_MEM_REF)
+			  && (TREE_CODE (base1) == MEM_REF
+			      || TREE_CODE (base1) == TARGET_MEM_REF)
+			  ? OEP_ADDRESS_OF : 0);
 }
 
 /* Compare two hashable_expr structures for equivalence.  They are