NOP conversions in X+CST+CST

Index: gcc/match.pd
===================================================================
--- gcc/match.pd	(revision 249413)
+++ gcc/match.pd	(working copy)
@@ -67,20 +67,34 @@  along with GCC; see the file COPYING3.
 			      BUILT_IN_L##FN \
 			      BUILT_IN_LL##FN) \
   (define_operator_list X##FN##L BUILT_IN_I##FN##L \
 				 BUILT_IN_L##FN##L \
 				 BUILT_IN_LL##FN##L)
 
 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.  */
 
 (for op (plus pointer_plus minus bit_ior bit_xor)
   (simplify
     (op @0 integer_zerop)
     (non_lvalue @0)))
 
 /* 0 +p index -> (type)index */
@@ -1289,32 +1303,58 @@  DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (simplify
     (plus:c (minus @0 @1) @1)
     @0)
   (simplify
    (minus @0 (plus:c @0 @1))
    (negate @1))
   (simplify
    (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)
    (simplify
     (outer_op (minus CONSTANT_CLASS_P@1 @0) CONSTANT_CLASS_P@2)
     (with { tree cst = const_binop (outer_op, type, @1, @2); }
      (if (cst && !TREE_OVERFLOW (cst))
       (minus { cst; } @0)))))
 
   /* CST1 - (CST2 - A) -> CST3 + A  */
Index: gcc/testsuite/gcc.dg/tree-ssa/addadd-2.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/addadd-2.c	(nonexistent)
+++ gcc/testsuite/gcc.dg/tree-ssa/addadd-2.c	(working copy)
@@ -0,0 +1,15 @@ 
+/* { 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" } } */
Index: gcc/testsuite/gcc.dg/tree-ssa/addadd.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/addadd.c	(revision 249413)
+++ gcc/testsuite/gcc.dg/tree-ssa/addadd.c	(working copy)
@@ -22,13 +22,13 @@  int i(int x){
   x += __INT_MAX__;
   x += __INT_MAX__;
   return x;
 }
 typedef int S __attribute__((vector_size(16)));
 void j(S*x){
   *x += __INT_MAX__;
   *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" } } */