On Wed, May 09, 2018 at 11:01:18AM -0400, Jason Merrill wrote:
> On Wed, May 9, 2018 at 10:47 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> > On Wed, May 09, 2018 at 10:40:26AM -0400, Jason Merrill wrote:
> >> On Wed, May 9, 2018 at 4:55 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> >> > On Tue, May 08, 2018 at 11:28:18PM -0400, Jason Merrill wrote:
> >> >> Maybe add a type parameter that defaults to size_type_node...
> >> >>
> >> >> > + ret = fold_convert_loc (loc, TREE_TYPE (expr),
> >> >> > + fold_offsetof_1 (TREE_TYPE (expr),
> >> >> > op0));
> >> >>
> >> >> ...and then this can be
> >> >>
> >> >> fold_offsetof (op0, TREE_TYPE (exp0))
> >> >
> >> > Like this then?
> >> >
> >> > + ret = fold_convert_loc (loc, TREE_TYPE (expr),
> >> > + fold_offsetof (op0, TREE_TYPE (expr)));
> >>
> >> I was thinking that we then wouldn't need the fold_convert at the call
> >> sites anymore, either.
> >
> > The patch only converts to non-pointer types, I'm not sure if it is
> > desirable to do the same with pointer types (and most of the other callers
> > don't use convert, but fold_convert which is significantly different, the
> > former is emitting diagnostics, the latter is just an conversion +
> > optimization).
>
> Is there a reason we can't use fold_convert for the non-pointer case,
> too? I don't think we're interested in diagnostics from this
> particular call.
This patch instead uses convert everywhere. Bootstrapped/regtested on
x86_64-linux and i686-linux, ok for trunk?
2018-05-09 Jakub Jelinek <ja...@redhat.com>
PR c++/85662
* c-common.h (fold_offsetof_1): Removed.
(fold_offsetof): Add TYPE argument defaulted to size_type_node and
CTX argument defaulted to ERROR_MARK.
* c-common.c (fold_offsetof_1): Renamed to ...
(fold_offsetof): ... this. Remove wrapper function. Add TYPE
argument, convert the pointer constant to TYPE and use size_binop
with PLUS_EXPR instead of fold_build_pointer_plus if type is not
a pointer type. Adjust recursive calls.
* c-fold.c (c_fully_fold_internal): Use fold_offsetof rather than
fold_offsetof_1, pass TREE_TYPE (expr) as TYPE to it and drop the
fold_convert_loc.
* c-typeck.c (build_unary_op): Use fold_offsetof rather than
fold_offsetof_1, pass argtype as TYPE to it and drop the
fold_convert_loc.
* cp-gimplify.c (cp_fold): Use fold_offsetof rather than
fold_offsetof_1, pass TREE_TYPE (x) as TYPE to it and drop the
fold_convert.
* g++.dg/ext/offsetof2.C: New test.
--- gcc/c-family/c-common.h.jj 2018-05-09 20:12:25.845258371 +0200
+++ gcc/c-family/c-common.h 2018-05-09 20:20:02.265649121 +0200
@@ -1033,8 +1033,8 @@ extern bool c_dump_tree (void *, tree);
extern void verify_sequence_points (tree);
-extern tree fold_offsetof_1 (tree, tree_code ctx = ERROR_MARK);
-extern tree fold_offsetof (tree);
+extern tree fold_offsetof (tree, tree = size_type_node,
+ tree_code ctx = ERROR_MARK);
extern int complete_array_type (tree *, tree, bool);
--- gcc/c-family/c-common.c.jj 2018-05-09 20:12:25.763258297 +0200
+++ gcc/c-family/c-common.c 2018-05-09 20:21:23.770718896 +0200
@@ -6168,10 +6168,11 @@ c_common_to_target_charset (HOST_WIDE_IN
/* Fold an offsetof-like expression. EXPR is a nested sequence of component
references with an INDIRECT_REF of a constant at the bottom; much like the
- traditional rendering of offsetof as a macro. Return the folded result. */
+ traditional rendering of offsetof as a macro. TYPE is the desired type of
+ the whole expression. Return the folded result. */
tree
-fold_offsetof_1 (tree expr, enum tree_code ctx)
+fold_offsetof (tree expr, tree type, enum tree_code ctx)
{
tree base, off, t;
tree_code code = TREE_CODE (expr);
@@ -6196,10 +6197,10 @@ fold_offsetof_1 (tree expr, enum tree_co
error ("cannot apply %<offsetof%> to a non constant address");
return error_mark_node;
}
- return TREE_OPERAND (expr, 0);
+ return convert (type, TREE_OPERAND (expr, 0));
case COMPONENT_REF:
- base = fold_offsetof_1 (TREE_OPERAND (expr, 0), code);
+ base = fold_offsetof (TREE_OPERAND (expr, 0), type, code);
if (base == error_mark_node)
return base;
@@ -6216,7 +6217,7 @@ fold_offsetof_1 (tree expr, enum tree_co
break;
case ARRAY_REF:
- base = fold_offsetof_1 (TREE_OPERAND (expr, 0), code);
+ base = fold_offsetof (TREE_OPERAND (expr, 0), type, code);
if (base == error_mark_node)
return base;
@@ -6273,23 +6274,16 @@ fold_offsetof_1 (tree expr, enum tree_co
/* Handle static members of volatile structs. */
t = TREE_OPERAND (expr, 1);
gcc_checking_assert (VAR_P (get_base_address (t)));
- return fold_offsetof_1 (t);
+ return fold_offsetof (t, type);
default:
gcc_unreachable ();
}
+ if (!POINTER_TYPE_P (type))
+ return size_binop (PLUS_EXPR, base, convert (type, off));
return fold_build_pointer_plus (base, off);
}
-
-/* Likewise, but convert it to the return type of offsetof. */
-
-tree
-fold_offsetof (tree expr)
-{
- return convert (size_type_node, fold_offsetof_1 (expr));
-}
-
/* *PTYPE is an incomplete array. Complete it with a domain based on
INITIAL_VALUE. If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
--- gcc/c/c-fold.c.jj 2018-05-09 20:12:25.496258072 +0200
+++ gcc/c/c-fold.c 2018-05-09 20:21:53.673744504 +0200
@@ -473,7 +473,7 @@ c_fully_fold_internal (tree expr, bool i
&& (op1 = get_base_address (op0)) != NULL_TREE
&& INDIRECT_REF_P (op1)
&& TREE_CONSTANT (TREE_OPERAND (op1, 0)))
- ret = fold_convert_loc (loc, TREE_TYPE (expr), fold_offsetof_1 (op0));
+ ret = fold_offsetof (op0, TREE_TYPE (expr));
else if (op0 != orig_op0 || in_init)
ret = in_init
? fold_build1_initializer_loc (loc, code, TREE_TYPE (expr), op0)
--- gcc/c/c-typeck.c.jj 2018-05-09 20:12:25.529258100 +0200
+++ gcc/c/c-typeck.c 2018-05-09 20:22:10.592758986 +0200
@@ -4676,7 +4676,7 @@ build_unary_op (location_t location, enu
if (val && INDIRECT_REF_P (val)
&& TREE_CONSTANT (TREE_OPERAND (val, 0)))
{
- ret = fold_convert_loc (location, argtype, fold_offsetof_1 (arg));
+ ret = fold_offsetof (arg, argtype);
goto return_build_unary_op;
}
--- gcc/cp/cp-gimplify.c.jj 2018-05-09 20:12:25.881258402 +0200
+++ gcc/cp/cp-gimplify.c 2018-05-09 20:22:35.639780430 +0200
@@ -2232,7 +2232,7 @@ cp_fold (tree x)
val = TREE_OPERAND (val, 0);
STRIP_NOPS (val);
if (TREE_CODE (val) == INTEGER_CST)
- return fold_convert (TREE_TYPE (x), fold_offsetof_1 (op0));
+ return fold_offsetof (op0, TREE_TYPE (x));
}
}
goto finish_unary;
--- gcc/testsuite/g++.dg/ext/offsetof2.C.jj 2018-05-09 20:20:02.272649127
+0200
+++ gcc/testsuite/g++.dg/ext/offsetof2.C 2018-05-09 20:20:02.272649127
+0200
@@ -0,0 +1,6 @@
+// PR c++/85662
+// { dg-do compile { target c++11 } }
+
+struct S { unsigned long x[31]; };
+struct T { bool b; S f; };
+static_assert (__builtin_offsetof (T, f.x[31 - 1]) == __builtin_offsetof (T,
f.x[30]), "");
Jakub
