> On 5 Jul 2021, at 14:23, Richard Biener <richard.guent...@gmail.com> wrote:
>
> On Mon, Jul 5, 2021 at 3:04 PM Iain Sandoe <i...@sandoe.co.uk> wrote:
>>
>> Hi Richard,
>>
>>> On 5 Jul 2021, at 11:50, Richard Biener via Gcc-patches
>>> <gcc-patches@gcc.gnu.org> wrote:
>>>
>>> On Sun, Jul 4, 2021 at 10:04 PM Iain Sandoe <i...@sandoe.co.uk> wrote:
>>
>>>> Several older compilers fail to build modern GCC because of missing
>>>> or incomplete C++11 support.
>>>>
>>>> (although the PR mentions clang, specifically, this has also been reported
>>>> for some GCC versions within the range that should be able to bootstrap
>>>> GCC)
>>>>
>>>> There are several possible solutions proposed in the PR, this one seems
>>>> the least invasive.
>>>>
>>>> The header is pulled into the gcov code that builds with C, so we have to
>>>> make the CTOR conditional on C++.
>>>>
>>>> tested on Darwin12 with xcode-6, bootstrapped on x86_64-darwin and linux.
>>>> OK for master / GCC-11?
>>>
>>> Hmm, what is specifically built with a C compiler? gcov.c not, I think.
>>
>> any C compilation that includes tm.h
>>
>> well, libgcc2 fails too on a quick check here - but ISTR there was
>> something in
>> libgcov and I checked with Martin that it was intentionally compiled with C
>> compiler.
>>
>>> Instead of commenting the CTOR, does it work to comment the whole
>>> stringop_algs
>>> type?
>>
>> I don’t think that will work because it’s in a header that’s transitively
>> included by tm.h
>> which is then included loads of places.
>>
>>> Also it seems on trunk this CTOR is no more?
>>
>> The addition of the CTOR is the fix for the C++ compile fail in the PR, the
>> conditional is
>> only there because the same header is compiled by C and C++.
>
> Whoops sorry - I was confused. The patch looks OK to me if you add a comment
> before the CTOR why it was added (maybe quoting the error that happens)
Thanks, pushed as below.
Iain
-------
X86: Provide a CTOR for stringop_algs [PR100246].
Several older compilers fail to build modern GCC because of missing
or incomplete C++11 support.
Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>
PR bootstrap/100246 - [11/12 Regression] GCC will not bootstrap with clang
3.4/3.5 [xcode 5/6, Darwin 12/13]
PR bootstrap/100246
gcc/ChangeLog:
* config/i386/i386.h (struct stringop_algs): Define a CTOR for
this type.
---
gcc/config/i386/i386.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 6e0340a4b60..03d176143fe 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -73,6 +73,15 @@ struct stringop_algs
{
const enum stringop_alg unknown_size;
const struct stringop_strategy {
+ /* Several older compilers delete the default constructor because of the
+ const entries (see PR100246). Manually specifying a CTOR works around
+ this issue. Since this header is used by code compiled with the C
+ compiler we must guard the addition. */
+#ifdef __cplusplus
+ stringop_strategy(int _max = -1, enum stringop_alg _alg = libcall,
+ int _noalign = false)
+ : max (_max), alg (_alg), noalign (_noalign) {}
+#endif
const int max;
const enum stringop_alg alg;
int noalign;
--
2.24.1
