NOP conversions in X+CST+CST

2017-06-21  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* match.pd (nop_convert): New predicate.
	((A +- CST1) +- CST2): Allow some NOP conversions.

gcc/testsuite/
	* gcc.dg/tree-ssa/addadd.c: Un-XFAIL.
	* gcc.dg/tree-ssa/addadd-2.c: New file.

From-SVN: r249447

gcc/ChangeLog

+2017-06-21  Marc Glisse  <marc.glisse@inria.fr>
+
+	* match.pd (nop_convert): New predicate.
+	((A +- CST1) +- CST2): Allow some NOP conversions.
+
 2017-06-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/81130

gcc/match.pd

@@ -74,6 +74,20 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (FLOOR)
 DEFINE_INT_AND_FLOAT_ROUND_FN (CEIL)
 DEFINE_INT_AND_FLOAT_ROUND_FN (ROUND)
 DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
+    
+/* As opposed to convert?, this still creates a single pattern, so
+   it is not a suitable replacement for convert? in all cases.  */
+(match (nop_convert @0)
+ (convert @0)
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))))
+(match (nop_convert @0)
+ (view_convert @0)
+ (if (VECTOR_TYPE_P (type) && VECTOR_TYPE_P (TREE_TYPE (@0))
+      && TYPE_VECTOR_SUBPARTS (type) == TYPE_VECTOR_SUBPARTS (TREE_TYPE (@0))
+      && tree_nop_conversion_p (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (@0))))))
+/* This one has to be last, or it shadows the others.  */
+(match (nop_convert @0)
+ @0) 
 
 /* Simplifications of operations with one constant operand and
    simplifications to constants or single values.  */
@@ -1296,18 +1310,44 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
    (minus @0 (minus @0 @1))
    @1)
 
-  /* (A +- CST1) +- CST2 -> A + CST3  */
+  /* (A +- CST1) +- CST2 -> A + CST3
+     Use view_convert because it is safe for vectors and equivalent for
+     scalars.  */
   (for outer_op (plus minus)
    (for inner_op (plus minus)
+	neg_inner_op (minus plus)
     (simplify
-     (outer_op (inner_op @0 CONSTANT_CLASS_P@1) CONSTANT_CLASS_P@2)
-     /* If the constant operation overflows we cannot do the transform
-	as we would introduce undefined overflow, for example
-	with (a - 1) + INT_MIN.  */
-     (with { tree cst = const_binop (outer_op == inner_op
-				     ? PLUS_EXPR : MINUS_EXPR, type, @1, @2); }
-      (if (cst && !TREE_OVERFLOW (cst))
-       (inner_op @0 { cst; } ))))))
+     (outer_op (nop_convert (inner_op @0 CONSTANT_CLASS_P@1))
+	       CONSTANT_CLASS_P@2)
+     /* If one of the types wraps, use that one.  */
+     (if (!ANY_INTEGRAL_TYPE_P (type) || TYPE_OVERFLOW_WRAPS (type))
+      (if (outer_op == PLUS_EXPR)
+       (plus (view_convert @0) (inner_op @2 (view_convert @1)))
+       (minus (view_convert @0) (neg_inner_op @2 (view_convert @1))))
+      (if (!ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
+	   || TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0)))
+       (if (outer_op == PLUS_EXPR)
+	(view_convert (plus @0 (inner_op (view_convert @2) @1)))
+	(view_convert (minus @0 (neg_inner_op (view_convert @2) @1))))
+       /* If the constant operation overflows we cannot do the transform
+	  directly as we would introduce undefined overflow, for example
+	  with (a - 1) + INT_MIN.  */
+       (if (types_match (type, @0))
+	(with { tree cst = const_binop (outer_op == inner_op
+					? PLUS_EXPR : MINUS_EXPR,
+					type, @1, @2); }
+	 (if (cst && !TREE_OVERFLOW (cst))
+	  (inner_op @0 { cst; } )
+	  /* X+INT_MAX+1 is X-INT_MIN.  */
+	  (if (INTEGRAL_TYPE_P (type) && cst
+	       && wi::eq_p (cst, wi::min_value (type)))
+	   (neg_inner_op @0 { wide_int_to_tree (type, cst); })
+	   /* Last resort, use some unsigned type.  */
+	   (with { tree utype = unsigned_type_for (type); }
+	    (view_convert (inner_op
+			   (view_convert:utype @0)
+			   (view_convert:utype
+			    { drop_tree_overflow (cst); })))))))))))))
 
   /* (CST1 - A) +- CST2 -> CST3 - A  */
   (for outer_op (plus minus)

gcc/testsuite/ChangeLog

+2017-06-21  Marc Glisse  <marc.glisse@inria.fr>
+
+	* gcc.dg/tree-ssa/addadd.c: Un-XFAIL.
+	* gcc.dg/tree-ssa/addadd-2.c: New file.
+
 2017-06-21  Tom de Vries  <tom@codesourcery.com>
 
 	* lib/target-supports.exp (add_options_for_stack_size): New proc.

gcc/testsuite/gcc.dg/tree-ssa/addadd-2.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-optimized" } */
+
+typedef int S __attribute__((vector_size(64)));
+typedef unsigned U __attribute__((vector_size(64)));
+void j(S*x){
+  *x += __INT_MAX__;
+  *x += __INT_MAX__;
+}
+void k(S*x){
+  U y = (U)(*x + __INT_MAX__);
+  *x = (S)(y + __INT_MAX__);
+}
+
+/* { dg-final { scan-tree-dump-not "2147483647" "optimized" } } */

gcc/testsuite/gcc.dg/tree-ssa/addadd.c

@@ -29,6 +29,6 @@ void j(S*x){
   *x += __INT_MAX__;
 }
 
-/* { dg-final { scan-tree-dump-times " \\+ 24;" 2 "optimized" { xfail *-*-* } } } */
-/* { dg-final { scan-tree-dump-times "\\(unsigned int\\)" 2 "optimized" { xfail *-*-* }  } } */
-/* { dg-final { scan-tree-dump-not "2147483647" "optimized" { xfail *-*-* }  } } */
+/* { dg-final { scan-tree-dump-times " \\+ 24;" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "\\(unsigned int\\)" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "2147483647" "optimized" } } */