tree-optimization/89317 - another pattern for &p->x != p + 4

As seen in the original testcase for PR89317 we are missing
comparison simplification patterns for &p->x != p + 4.  Fixed
by making an existing one apply.  To make the pattern apply
during CCP we need to simplify ccp_fold to not use GENERIC
folding of conditions but also use GIMPLE folding.

	PR tree-optimization/89317
	* tree-ssa-ccp.cc (ccp_fold): Handle GIMPLE_COND via
	gimple_fold_stmt_to_constant_1.
	* match.pd (&a != &a + c): Apply to pointer_plus with non-ADDR_EXPR
	base as well.

	* gcc.dg/tree-ssa/pr89317.c: Amend.

diff --git a/gcc/match.pd b/gcc/match.pd
index ba83c69734f977ad40dfddfcd80030bfd8b70cef..3517605c04dc61be0c699933adee2f3a748bc915 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2263,7 +2263,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 /* (&a + b) !=/== (&a[1] + c) -> (&a[0] - &a[1]) + b !=/== c */
 (for neeq (ne eq)
  (simplify
-  (neeq:c ADDR_EXPR@0 (pointer_plus ADDR_EXPR@2 @3))
+  (neeq:c ADDR_EXPR@0 (pointer_plus @2 @3))
    (with { poly_int64 diff; tree inner_type = TREE_TYPE (@3);}
     (if (ptr_difference_const (@0, @2, &diff))
      (neeq { build_int_cst_type (inner_type, diff); } @3))))

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c
index 0d0a049454f0c1de3a6618e2cd26dd7916f0e44d..0c8f2f53a4555994eea1b09be1127c5e480f154d 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c
@@ -10,4 +10,21 @@ int foo (struct b *x)
   return b - a;
 }
 
+int bar (struct b *x)
+{
+  int *a = x->data;
+  int *b = ((int*)x) + 4;
+  if (a != b)
+    return 1;
+  return 0;
+}
+
+int baz (struct b *x)
+{
+  int *a = x->data;
+  int *b = ((int*)x) + 4;
+  return (a != b);
+}
+
 /* { dg-final { scan-tree-dump "return 4;" "ccp1" } } */
+/* { dg-final { scan-tree-dump-times "return 1;" 2 "ccp1" } } */

diff --git a/gcc/tree-ssa-ccp.cc b/gcc/tree-ssa-ccp.cc
index 69fd7f1d11d86ad8708126dada43b02437280499..68e69bfe129b40756fd00448ca5af8e16998521b 100644 (file)
--- a/gcc/tree-ssa-ccp.cc
+++ b/gcc/tree-ssa-ccp.cc
@@ -1271,24 +1271,15 @@ valueize_op_1 (tree op)
 static tree
 ccp_fold (gimple *stmt)
 {
-  location_t loc = gimple_location (stmt);
   switch (gimple_code (stmt))
     {
-    case GIMPLE_COND:
-      {
-        /* Handle comparison operators that can appear in GIMPLE form.  */
-        tree op0 = valueize_op (gimple_cond_lhs (stmt));
-        tree op1 = valueize_op (gimple_cond_rhs (stmt));
-        enum tree_code code = gimple_cond_code (stmt);
-        return fold_binary_loc (loc, code, boolean_type_node, op0, op1);
-      }
-
     case GIMPLE_SWITCH:
       {
        /* Return the constant switch index.  */
         return valueize_op (gimple_switch_index (as_a <gswitch *> (stmt)));
       }
 
+    case GIMPLE_COND:
     case GIMPLE_ASSIGN:
     case GIMPLE_CALL:
       return gimple_fold_stmt_to_constant_1 (stmt,