[Bug libstdc++/68133] constexpr basic_string_view(const _CharT* __str)

["daniel.kruegler at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68133

Daniel Krügler <daniel.kruegler at googlemail dot com> changed:

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--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
The implementation matches the required semantics (see
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4529.html). Please
note that std::char_traits::length is not constexpr because it is specified
that way and this is a known library issue, see

http://cplusplus.github.io/LWG/lwg-active.html#2232

The reason why the discussed string view constructor is nonetheless declared as
constexpr is due to the fact that a user *could* instantiate it with a
user-defined char trait class (not necessarily a specialization of
std::char_traits) that *has* a constexpr length function.

Based on this argumentation this issue looks invalid to me.
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Subject: [Bug target/68124] [6 Regression] Many i386 test failures
Date: Wed, 28 Oct 2015 21:12:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68124

--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Richard Henderson from comment #5)
> Works for me at r229501.
> 
> spawn -ignore SIGHUP /home/rth/gcc/bld/gcc/xgcc -B/home/rth/gcc/bld/gcc/
> /home/rth/gcc/git-master/gcc/testsuite/gcc.dg/vect/pr64421.c -mtune=corei7
> -fno-diagnostics-show-caret -fdiagnostics-color=never -msse2
> -ftree-vectorize -fno-vect-cost-model -fno-common -O2
> -fdump-tree-vect-details -fopenmp-simd -mavx -lm -o ./pr64421.exe
> PASS: gcc.dg/vect/pr64421.c (test for excess errors)

This particular test only fails with -m64:

[hjl@gnu-6 gcc]$ ./xgcc -B./   -S 
/export/gnu/import/git/sources/gcc/gcc/testsuite/gcc.dg/vect/pr64421.c 
-mtune=corei7 -fno-diagnostics-show-caret -fdiagnostics-color=never -msse2
-ftree-vectorize -fno-vect-cost-model -fno-common -O2 -fdump-tree-vect-details
-fopenmp-simd -mavx -lm -m32
[hjl@gnu-6 gcc]$ ./xgcc -B./   -S 
/export/gnu/import/git/sources/gcc/gcc/testsuite/gcc.dg/vect/pr64421.c 
-mtune=corei7 -fno-diagnostics-show-caret -fdiagnostics-color=never -msse2
-ftree-vectorize -fno-vect-cost-model -fno-common -O2 -fdump-tree-vect-details
-fopenmp-simd -mavx -lm -m64
/export/gnu/import/git/sources/gcc/gcc/testsuite/gcc.dg/vect/pr64421.c: In
function ‘*bar.simdclone.2’:
/export/gnu/import/git/sources/gcc/gcc/testsuite/gcc.dg/vect/pr64421.c:16:1:
internal compiler error: in gen_reg_rtx, at emit-rtl.c:1031
0x9a9877 gen_reg_rtx(machine_mode)
        /export/gnu/import/git/sources/gcc/gcc/emit-rtl.c:1031
0x9c9946 copy_to_reg(rtx_def*)
        /export/gnu/import/git/sources/gcc/gcc/explow.c:570
0xd3b5b2 gen_lowpart_general(machine_mode, rtx_def*)
        /export/gnu/import/git/sources/gcc/gcc/rtlhooks.c:62
0x1412d91 gen_split_392(rtx_insn*, rtx_def**)
        /export/gnu/import/git/sources/gcc/gcc/config/i386/sse.md:17100
0x15c0531 split_23
        /export/gnu/import/git/sources/gcc/gcc/config/i386/sse.md:17098
0x15c12ea split_24
        /export/gnu/import/git/sources/gcc/gcc/config/i386/i386.md:4803
0x15c4e52 split_insns(rtx_def*, rtx_insn*)
        /export/gnu/import/git/sources/gcc/gcc/config/i386/i386.md:15867
0x9afb29 try_split(rtx_def*, rtx_insn*, int)
        /export/gnu/import/git/sources/gcc/gcc/emit-rtl.c:3664
0xcd15d7 split_insn
        /export/gnu/import/git/sources/gcc/gcc/recog.c:2874
0xcd18af split_all_insns()
        /export/gnu/import/git/sources/gcc/gcc/recog.c:2964
0xcd36d3 rest_of_handle_split_after_reload
        /export/gnu/import/git/sources/gcc/gcc/recog.c:3900
0xcd3724 execute
        /export/gnu/import/git/sources/gcc/gcc/recog.c:3929
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
[hjl@gnu-6 gcc]$
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From: "hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/68124] [6 Regression] Many i386 test failures
Date: Wed, 28 Oct 2015 21:13:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idh124

H.J. Lu <hjl.tools at gmail dot com> changed:

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