re PR tree-optimization/56049 (Simplification to constants not done)

2019-04-16  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/56049
	* tree-ssa-loop-im.c (mem_ref_hasher::equal): Elide alias-set
	equality check if alias-set zero will prevail.

	* gfortran.dg/pr56049.f90: New testcase.

From-SVN: r270378

gcc/ChangeLog

+2019-04-16  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/56049
+	* tree-ssa-loop-im.c (mem_ref_hasher::equal): Elide alias-set
+	equality check if alias-set zero will prevail.
+
 2019-04-15  Jeff Law  <law@redhat.com>
 
 	* config/microblaze/microblaze.c (microblaze_expand_block_move): Treat

gcc/testsuite/ChangeLog

+2019-04-16  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/56049
+	* gfortran.dg/pr56049.f90: New testcase.
+
 2019-04-15  Richard Biener  <rguenther@suse.de>
 
 	PR debug/90074

gcc/testsuite/gfortran.dg/pr56049.f90

+! { dg-do compile }
+! { dg-options "-O3 -fdump-tree-optimized" }
+
+program inline
+
+    integer i
+    integer a(8,8), b(8,8)
+
+    a = 0
+    do i = 1, 10000000
+        call add(b, a, 1)
+        a = b
+    end do
+
+    print *, a
+
+contains
+
+    subroutine add(b, a, o)
+        integer, intent(inout) :: b(8,8)
+        integer, intent(in) :: a(8,8), o
+        b = a + o
+    end subroutine add
+
+end program inline
+
+! Check there's no loop left, just two bb 2 in two functions.
+! { dg-final { scan-tree-dump-times "<bb \[0-9\]*>" 2 "optimized" } }
+! { dg-final { scan-tree-dump-times "<bb 2>" 2 "optimized" } }

gcc/tree-ssa-loop-im.c

@@ -178,7 +178,17 @@ mem_ref_hasher::equal (const im_mem_ref *mem1, const ao_ref *obj2)
 	    && known_eq (mem1->mem.size, obj2->size)
 	    && known_eq (mem1->mem.max_size, obj2->max_size)
 	    && mem1->mem.volatile_p == obj2->volatile_p
-	    && mem1->mem.ref_alias_set == obj2->ref_alias_set
+	    && (mem1->mem.ref_alias_set == obj2->ref_alias_set
+		/* We are not canonicalizing alias-sets but for the
+		   special-case we didn't canonicalize yet and the
+		   incoming ref is a alias-set zero MEM we pick
+		   the correct one already.  */
+		|| (!mem1->ref_canonical
+		    && (TREE_CODE (obj2->ref) == MEM_REF
+			|| TREE_CODE (obj2->ref) == TARGET_MEM_REF)
+		    && obj2->ref_alias_set == 0)
+		/* Likewise if there's a canonical ref with alias-set zero.  */
+		|| (mem1->ref_canonical && mem1->mem.ref_alias_set == 0))
 	    && types_compatible_p (TREE_TYPE (mem1->mem.ref),
 				   TREE_TYPE (obj2->ref)));
   else