[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 --- Comment #10 from CVS Commits --- The master branch has been updated by Jonathan Wakely : https://gcc.gnu.org/g:367740bf6d3a6627798b3955e5d85efc7549ef50 commit r13-787-g367740bf6d3a6627798b3955e5d85efc7549ef50 Author: Jonathan Wakely Date: Thu May 26 21:32:55 2022 +0100 libstdc++: Fix narrowing conversions for 16-bit size_t [PR105681] On a 16-bit target such as msp430 we get errors about narrowing long values to size_t, which is only 16-bit. When --enable-libstdcxx-pch is used the header breaks the build because of these narrowing errors. libstdc++-v3/ChangeLog: PR libstdc++/105681 * include/ext/pb_ds/detail/resize_policy/hash_prime_size_policy_imp.hpp: Limit ga_sizes array to values that fit in size_t. * include/ext/random [__SIZE_WIDTH < 32] (sfmt86243) (sfmt86243_64, sfmt132049, sfmt132049_64, sfmt216091) (sfmt216091_64): Do not declare.
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681
--- Comment #9 from Jonathan Wakely ---
Ah, and I didn't see this when building for msp430 because I used
--disable-libstdcxx-pch and that means the build doesn't depend on the
header.
I can now reproduce the build failure, and the patch in comment 6 fixes the
failures in , but then we fail later:
/tmp/msp430/msp430-elf/libstdc++-v3/include/ext/pb_ds/detail/resize_policy/hash_prime_size_policy_imp.hpp:73:32:
error: narrowing conversion of '116731' from 'long unsigned int' to
'std::size_t' {aka 'unsigned int'} [-Wnarrowing]
73 | /* 14*/ 116731ul,
|^~~~
Those are also non-standard extensions. Maybe we should just not install the
precompiled header for on 16-bit targets.
As a workaround until I fix all the problems, you can use
--disable-libstdcxx-pch
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681
--- Comment #8 from Jonathan Wakely ---
And it was indeed something I asked for, see r12-2355
c++: Don't hide narrowing errors in system headers
Jonathan pointed me at this issue where
constexpr unsigned f() { constexpr int n = -1; return unsigned{n}; }
is accepted in system headers, despite the narrowing conversion from
a constant. I suspect that whereas narrowing warnings should be
disabled, ill-formed narrowing of constants should be a hard error
(which can still be disabled by -Wno-narrowing).
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 --- Comment #7 from Jonathan Wakely --- (In reply to Richard Biener from comment #4) > possibly the system header diagnostic changes? Yes, the narrowing check here was PR c++/57891 which was fixed for GCC 9. But it was still allowed in system headers until GCC 12.
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 Jonathan Wakely changed: What|Removed |Added Ever confirmed|0 |1 Target Milestone|--- |12.2 Status|UNCONFIRMED |ASSIGNED Last reconfirmed||2022-05-26 Assignee|unassigned at gcc dot gnu.org |redi at gcc dot gnu.org --- Comment #6 from Jonathan Wakely --- I think the compiler might have got stricter about diagnosing narrowing conversions in non-type template arguments (I think I even reported a bug saying it should do that!) The problem is that size_t is a 16-bit unsigned int, so too small for the values we use in the specializations: template class simd_fast_mersenne_twister_engine // ... typedef simd_fast_mersenne_twister_engine sfmt86243; We could change the size_t there to be a type with at least 32 bits to make it work, but I think the right fix is to simply not defined those typedefs that don't fit in 16 bits: --- a/libstdc++-v3/include/ext/random +++ b/libstdc++-v3/include/ext/random @@ -346,6 +346,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION 0xa3ac4000U, 0xecc1327aU> sfmt44497_64; +#if __SIZE_WIDTH__ >= 32 typedef simd_fast_mersenne_twister_engine sfmt216091_64; +#endif // __SIZE_WIDTH__ >= 32 #endif // __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ Everything in is a non-standard extension, so we're under no obligation to provide any of it for standard conformance.
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 --- Comment #5 from David Summers --- Yes I can confirm that going back to gcc-11.2.0 - and it works again, that being the only change. It explains how I got the headers, on my first build I used 11.2.0; whilst it was building saw that gcc-12 was available, so downloaded for a second pass (always like to do two passes - to make sure that everything knows what else is set up). So problem is in gcc-12
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 --- Comment #4 from Richard Biener --- possibly the system header diagnostic changes?
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681
Mikael Pettersson changed:
What|Removed |Added
CC||mikpelinux at gmail dot com
--- Comment #3 from Mikael Pettersson ---
I can reproduce in a cross to --target=msp430-unknown-elf
--enable-languages=c,c++ with binutils-2.38 and newlib-4.2.0.20211231.
gcc-11.3.0 builds fine, but gcc-12.1.0 build fails with
In file included from
/mnt/scratch/cross/sources/gcc-12.1.0/libstdc++-v3/include/precompiled/extc++.h:61:
/mnt/scratch/cross/objdir-gcc/msp430-unknown-elf/libstdc++-v3/include/ext/random:355:69:
error: narrowing conversion of '86243' from 'long int' to 'unsigned int'
[-Wnarrowing]
355 | 0xU, 0xe9528d85U>
| ^
(several more)
and
In file included from
/mnt/scratch/cross/objdir-gcc/msp430-unknown-elf/libstdc++-v3/include/ext/pb_ds/hash_policy.hpp:475,
from
/mnt/scratch/cross/objdir-gcc/msp430-unknown-elf/libstdc++-v3/include/ext/pb_ds/detail/standard_policies.hpp:45,
from
/mnt/scratch/cross/objdir-gcc/msp430-unknown-elf/libstdc++-v3/include/ext/pb_ds/assoc_container.hpp:47,
from
/mnt/scratch/cross/sources/gcc-12.1.0/libstdc++-v3/include/precompiled/extc++.h:72:
/mnt/scratch/cross/objdir-gcc/msp430-unknown-elf/libstdc++-v3/include/ext/pb_ds/detail/resize_policy/hash_prime_size_policy_imp.hpp:73:32:
error: narrowing conversion of '116731' from 'long unsigned int' to
'std::size_t' {aka 'unsigned int'} [-Wnarrowing]
73 | /* 14*/ 116731ul,
|^~~~
(many more)
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 --- Comment #2 from David Summers --- I suspect its the newlib includes that trigger the problem. As it I did one compile, where the configure grabbed the host includes (and 64bit system); and that compile I think worked fine. My problem though, as my target is a small 16bit cpu, I need the smallest library, and newlib nano seems to work well - so that will be the library on the machine where the code is run ..,
[Bug libstdc++/105681] libstdc++-v3 fails to build on msp430
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105681 Jonathan Wakely changed: What|Removed |Added Keywords||build --- Comment #1 from Jonathan Wakely --- Odd, that isn't new code and last time I built for msp430 I thought it worked ok. I'll look into it.
