Re: [patch c++]: Fix PR/53904
Sorry, missed to add needed hunk to disable pedantic warnings for this testcase. Committed it as obvious fix at rev 218130. Kai
Re: [patch c++]: Fix PR/53904
On Wed, Nov 26, 2014 at 9:52 AM, Kai Tietz wrote: > Ok. Adjusted patch attached. Nevertheless we should use here > unsigned HWI instead of possible truncation to signed int. I admit > that it is unlikely to have more then 2^31 elements, but well > > Ok for apply with adjusted ChangeLog? > > Regards, > Kai > On Linux/x86, the testcase fails with output is: /export/gnu/import/git/gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C: In instantiation of 'struct foo<0>':^M /export/gnu/import/git/gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C:10:26: required from here^M /export/gnu/import/git/gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C:6:12: error: ISO C++ forbids zero-size array [-Wpedantic]^M FAIL: g++.dg/cpp0x/pr63904.C -std=c++11 (test for excess errors) H.J.
Re: [patch c++]: Fix PR/53904
OK, thanks. Jason
Re: [patch c++]: Fix PR/53904
Ok. Adjusted patch attached. Nevertheless we should use here
unsigned HWI instead of possible truncation to signed int. I admit
that it is unlikely to have more then 2^31 elements, but well
Ok for apply with adjusted ChangeLog?
Regards,
Kai
Index: constexpr.c
===
--- constexpr.c (Revision 218076)
+++ constexpr.c (Arbeitskopie)
@@ -2013,12 +2013,12 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tre
bool *non_constant_p, bool *overflow_p)
{
tree elttype = TREE_TYPE (atype);
- int max = tree_to_shwi (array_type_nelts (atype));
+ unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype));
verify_ctor_sanity (ctx, atype);
vec **p = &CONSTRUCTOR_ELTS (ctx->ctor);
vec_alloc (*p, max + 1);
bool pre_init = false;
- int i;
+ unsigned HOST_WIDE_INT i;
/* For the default constructor, build up a call to the default
constructor of the element type. We only need to handle class types
@@ -2043,7 +2043,7 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tre
pre_init = true;
}
- for (i = 0; i <= max; ++i)
+ for (i = 0; i < max; ++i)
{
tree idx = build_int_cst (size_type_node, i);
tree eltinit;
Re: [patch c++]: Fix PR/53904
On 11/20/2014 02:48 PM, Kai Tietz wrote: this issue fixes a type-overflow issue caused by trying to cast a UHWI via tree_to_shwi. As soon as value gets larger then SHWI_MAX, we get an error for it. So we need to cast it via tree_to_uhwi, and then casting it to the signed variant. The problem seems to be with zero-length arrays getting -1 from array_type_nelts. Let's use array_type_nelts_top instead so we don't ever see negative values. Jason
Re: [patch c++]: Fix PR/53904
On Thu, Nov 20, 2014 at 8:48 PM, Kai Tietz wrote:
> Hello,
>
> this issue fixes a type-overflow issue caused by trying to cast a UHWI
> via tree_to_shwi.
> As soon as value gets larger then SHWI_MAX, we get an error for it.
> So we need to cast it
> via tree_to_uhwi, and then casting it to the signed variant.
I think it's better to handle the degenerate case (no element) explicitely.
And I would think that sth like "nelts" should have a positive result,
thus why is 'max' not unsigned? Also 'max' and using 'nelts' looks
like a mismatch? max == nelts - 1. Ah, because array_type_nelts
returns nelts - 1 ... how useful ;)
Still you want to special-case the array_type_nelts == -1 case.
Richard.
> ChangeLog
>
> 2014-11-20 Kai Tietz
>
> PR c++/63904
> * constexpr.c (cxx_eval_vec_init_1): Avoid
> type-overflow issue.
>
> 2014-11-20 Kai Tietz
>
> PR c++/63904
> * g++.dg/cpp0x/pr63904.C: New.
>
>
> Regression tested for x86_64-unknown-linux-gnu. Ok for apply?
>
> Regards,
> Kai
>
> Index: gcc/gcc/cp/constexpr.c
> ===
> --- gcc.orig/gcc/cp/constexpr.c
> +++ gcc/gcc/cp/constexpr.c
> @@ -2006,12 +2050,12 @@ cxx_eval_vec_init_1 (const constexpr_ctx
> bool *non_constant_p, bool *overflow_p)
> {
>tree elttype = TREE_TYPE (atype);
> - int max = tree_to_shwi (array_type_nelts (atype));
> + HOST_WIDE_INT max = (HOST_WIDE_INT) tree_to_uhwi (array_type_nelts
> (atype));
>verify_ctor_sanity (ctx, atype);
>vec **p = &CONSTRUCTOR_ELTS (ctx->ctor);
>vec_alloc (*p, max + 1);
>bool pre_init = false;
> - int i;
> + HOST_WIDE_INT i;
>
>/* For the default constructor, build up a call to the default
> constructor of the element type. We only need to handle class types
> Index: gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C
> ===
> --- /dev/null
> +++ gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C
> @@ -0,0 +1,13 @@
> +// { dg-do compile { target c++11 } }
> +
> +template
> +struct foo {
> +constexpr foo() : a() {}
> +int a[N];
> +};
> +
> +int main() {
> + foo< (foo<1>{}).a[0] > f;
> + return 0;
> +}
> +
[patch c++]: Fix PR/53904
Hello,
this issue fixes a type-overflow issue caused by trying to cast a UHWI
via tree_to_shwi.
As soon as value gets larger then SHWI_MAX, we get an error for it.
So we need to cast it
via tree_to_uhwi, and then casting it to the signed variant.
ChangeLog
2014-11-20 Kai Tietz
PR c++/63904
* constexpr.c (cxx_eval_vec_init_1): Avoid
type-overflow issue.
2014-11-20 Kai Tietz
PR c++/63904
* g++.dg/cpp0x/pr63904.C: New.
Regression tested for x86_64-unknown-linux-gnu. Ok for apply?
Regards,
Kai
Index: gcc/gcc/cp/constexpr.c
===
--- gcc.orig/gcc/cp/constexpr.c
+++ gcc/gcc/cp/constexpr.c
@@ -2006,12 +2050,12 @@ cxx_eval_vec_init_1 (const constexpr_ctx
bool *non_constant_p, bool *overflow_p)
{
tree elttype = TREE_TYPE (atype);
- int max = tree_to_shwi (array_type_nelts (atype));
+ HOST_WIDE_INT max = (HOST_WIDE_INT) tree_to_uhwi (array_type_nelts (atype));
verify_ctor_sanity (ctx, atype);
vec **p = &CONSTRUCTOR_ELTS (ctx->ctor);
vec_alloc (*p, max + 1);
bool pre_init = false;
- int i;
+ HOST_WIDE_INT i;
/* For the default constructor, build up a call to the default
constructor of the element type. We only need to handle class types
Index: gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C
===
--- /dev/null
+++ gcc/gcc/testsuite/g++.dg/cpp0x/pr63904.C
@@ -0,0 +1,13 @@
+// { dg-do compile { target c++11 } }
+
+template
+struct foo {
+constexpr foo() : a() {}
+int a[N];
+};
+
+int main() {
+ foo< (foo<1>{}).a[0] > f;
+ return 0;
+}
+
