tree.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Delete.

	* tree.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Delete.
	* fold-const.c (fold_comparison, fold_binary_loc): Delete use of
	above macro.
	* match.pd: Ditto in address comparison pattern.

	gcc/testsuite
	* gcc.dg/no-strict-overflow-7.c: Revise comment and test string.
	* gcc.dg/tree-ssa/pr81388-1.c: Ditto.

From-SVN: r250765

gcc/ChangeLog

 2017-08-01  Bin Cheng  <bin.cheng@arm.com>
 
+	* tree.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Delete.
+	* fold-const.c (fold_comparison, fold_binary_loc): Delete use of
+	above macro.
+	* match.pd: Ditto in address comparison pattern.
+
+2017-08-01  Bin Cheng  <bin.cheng@arm.com>
+
 	PR tree-optimization/81627
 	* tree-predcom.c (prepare_finalizers): Always rewrite into loop
 	closed ssa form for store-store chain.

gcc/fold-const.c

@@ -8458,14 +8458,9 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
 	{
 	  /* We can fold this expression to a constant if the non-constant
 	     offset parts are equal.  */
-	  if ((offset0 == offset1
+	  if (offset0 == offset1
 	      || (offset0 && offset1
 		  && operand_equal_p (offset0, offset1, 0)))
-	      && (equality_code
-		  || (indirect_base0
-		      && (DECL_P (base0) || CONSTANT_CLASS_P (base0)))
-		  || POINTER_TYPE_OVERFLOW_UNDEFINED))
-
 	    {
 	      if (!equality_code
 		  && bitpos0 != bitpos1
@@ -8500,11 +8495,7 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
 	     because pointer arithmetic is restricted to retain within an
 	     object and overflow on pointer differences is undefined as of
 	     6.5.6/8 and /9 with respect to the signed ptrdiff_t.  */
-	  else if (bitpos0 == bitpos1
-		   && (equality_code
-		       || (indirect_base0
-			   && (DECL_P (base0) || CONSTANT_CLASS_P (base0)))
-		       || POINTER_TYPE_OVERFLOW_UNDEFINED))
+	  else if (bitpos0 == bitpos1)
 	    {
 	      /* By converting to signed sizetype we cover middle-end pointer
 	         arithmetic which operates on unsigned pointer types of size
@@ -9590,7 +9581,7 @@ fold_binary_loc (location_t loc,
 
 	  /* With undefined overflow prefer doing association in a type
 	     which wraps on overflow, if that is one of the operand types.  */
-	  if ((POINTER_TYPE_P (type) && POINTER_TYPE_OVERFLOW_UNDEFINED)
+	  if (POINTER_TYPE_P (type)
 	      || (INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type)))
 	    {
 	      if (INTEGRAL_TYPE_P (TREE_TYPE (arg0))
@@ -9604,7 +9595,7 @@ fold_binary_loc (location_t loc,
 
 	  /* With undefined overflow we can only associate constants with one
 	     variable, and constants whose association doesn't overflow.  */
-	  if ((POINTER_TYPE_P (atype) && POINTER_TYPE_OVERFLOW_UNDEFINED)
+	  if (POINTER_TYPE_P (atype)
 	      || (INTEGRAL_TYPE_P (atype) && !TYPE_OVERFLOW_WRAPS (atype)))
 	    {
 	      if (var0 && var1)

gcc/match.pd

@@ -3223,14 +3223,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 		    || TREE_CODE (base1) == STRING_CST))
          equal = (base0 == base1);
      }
-     (if (equal == 1
-	  && (cmp == EQ_EXPR || cmp == NE_EXPR
-	      /* If the offsets are equal we can ignore overflow.  */
-	      || off0 == off1
-	      || POINTER_TYPE_OVERFLOW_UNDEFINED
-	      /* Or if we compare using pointers to decls or strings.  */
-	      || (POINTER_TYPE_P (TREE_TYPE (@2))
-		  && (DECL_P (base0) || TREE_CODE (base0) == STRING_CST))))
+     (if (equal == 1)
       (switch
        (if (cmp == EQ_EXPR)
 	{ constant_boolean_node (off0 == off1, type); })

gcc/testsuite/ChangeLog

 2017-08-01  Bin Cheng  <bin.cheng@arm.com>
 
+	* gcc.dg/no-strict-overflow-7.c: Revise comment and test string.
+	* gcc.dg/tree-ssa/pr81388-1.c: Ditto.
+
+2017-08-01  Bin Cheng  <bin.cheng@arm.com>
+
 	PR tree-optimization/81627
 	* gcc.dg/tree-ssa/pr81627.c: New.
 

gcc/testsuite/gcc.dg/no-strict-overflow-7.c

@@ -3,8 +3,8 @@
 
 /* Source: Ian Lance Taylor.  Dual of strict-overflow-6.c.  */
 
-/* We can only simplify the conditional when using strict overflow
-   semantics.  */
+/* We can simplify the conditional because pointer overflow always has
+   undefined semantics.  */
 
 int
 foo (char* p)
@@ -12,4 +12,4 @@ foo (char* p)
   return p + 1000 < p;
 }
 
-/* { dg-final { scan-tree-dump "\[+\]\[ \]*1000" "optimized" } } */
+/* { dg-final { scan-tree-dump "return 0" "optimized" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr81388-1.c

 /* { dg-do compile } */
-/* { dg-options "-O2 -fno-strict-overflow -fdump-tree-ivcanon-details" } */
+/* { dg-options "-O2 -fno-strict-overflow -fdump-tree-tailc-details" } */
 
 void bar();
 void foo(char *dst)
@@ -11,4 +11,6 @@ void foo(char *dst)
   } while (dst < end);
 }
 
-/* { dg-final { scan-tree-dump-times " zero if " 1 "ivcanon" } } */
+/* The loop only iterates once because pointer overflow always has undefined
+   semantics.  As a result, call to bar becomes tail call.  */
+/* { dg-final { scan-tree-dump-times "Found tail call " 1 "tailc" } } */

gcc/tree.h

@@ -859,9 +859,6 @@ extern void omp_clause_range_check_failed (const_tree, const char *, int,
    && !TYPE_OVERFLOW_WRAPS (TYPE)			\
    && (flag_sanitize & SANITIZE_SI_OVERFLOW))
 
-/* True if pointer types have undefined overflow.  */
-#define POINTER_TYPE_OVERFLOW_UNDEFINED (!flag_wrapv)
-
 /* Nonzero in a VAR_DECL or STRING_CST means assembler code has been written.
    Nonzero in a FUNCTION_DECL means that the function has been compiled.
    This is interesting in an inline function, since it might not need