[Bug c++/62241] C++14 generalized lambda capture doesn't work with uniform initialization syntax.

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62241

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

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--- Comment #5 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
(In reply to Andrew Pinski from comment #2)
> Have you tried 5.x yet?

Trying 5.0.0 20140826 (experimental) the outcome is still the same rejection
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From: "carrot at google dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/62262] aarch64 gcc generates invalid assembler
Date: Tue, 26 Aug 2014 21:59:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idb262

--- Comment #5 from Carrot <carrot at google dot com> ---
(In reply to amker from comment #2)
> (In reply to Andrew Pinski from comment #1)
> > (insn 27 26 40 5 (set (reg:SI 73 [ D.2590 ])
> >         (and:SI (ashift:SI (reg/v:SI 74 [ value ])
> >                 (const_int 32 [0x20]))
> >             (const_int 8388607 [0x7fffff]))) t7.c:13 611
> > {*andim_ashiftsi_bfiz}
> >      (expr_list:REG_DEAD (reg/v:SI 74 [ value ])
> >         (nil)))
> >
> > Confirmed.
> >
> >   "exact_log2 ((INTVAL (operands[3]) >> INTVAL (operands[2])) + 1) >= 0
> >    && (INTVAL (operands[3]) & ((1 << INTVAL (operands[2])) - 1)) == 0"
> >
> >
> > In fact we invoke undefined behavior inside the compiler too due to the
> > shift there.
>
> Since it's undefined code, how should we handle it in GCC?  Should we give
> warning messages as accurate as possible?  But that sounds impractical
> either, since "value << 1" and "value <<= zeros" could be undefined too.

Actually the original source code is guarded by assert, and the parameter
passed to CLZ can be guaranteed not 0, so "value <<= zeros" is well defined in
our original source code.