Bug#561249: Spurious warning with -Wconversion (uint16_t/htons) in -O2 mode
Package: g++-4.4
Version: 4.4.2-5
Severity: normal
The bug may be rather in libc6-dev, which defines:
htons to __bswap16 if optimize && little endian,
and __bswap16 in bits/byteswap.h
# define __bswap_16(x) \
(__extension__ \
({ register unsigned short int __v, __x = (x); \
if (__builtin_constant_p (__x)) \
__v = __bswap_constant_16 (__x); \
else \
__asm__ ("rorw $8, %w0" \
: "=r" (__v) \
: "0" (__x) \
: "cc"); \
__v; }))
I'm not expert enough with gcc inline assembly to guess what the exact
problem is, but it is definitely in this macro or the way gcc handles it,
but since gcc <= 4.2 noes not show any warning in optimize it, I'd rather
think it is a gcc (4.3 & 4.4) regression
-- System Information:
Debian Release: squeeze/sid
APT prefers unstable
APT policy: (990, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: i386 (i686)
Kernel: Linux 2.6.31-1-686 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages g++-4.4 depends on:
ii gcc-4.4 4.4.2-5 The GNU C compiler
ii gcc-4.4-base 4.4.2-5 The GNU Compiler Collection (base
ii libc6 2.10.2-2 GNU C Library: Shared libraries
ii libgmp3c2 2:4.3.1+dfsg-3 Multiprecision arithmetic library
ii libmpfr1ldbl 2.4.2-3 multiple precision floating-point
ii libstdc++6-4.4-dev 4.4.2-5 The GNU Standard C++ Library v3 (d
g++-4.4 recommends no packages.
Versions of packages g++-4.4 suggests:
pn g++-4.4-multilib <none> (no description available)
pn gcc-4.4-doc <none> (no description available)
pn libstdc++6-4.4-dbg <none> (no description available)
-- no debconf information
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