inline float quickBinaryToFloat( unsigned const& in )
{
return reinterpret_cast< float const& >( in ) ;
}
float foo( unsigned x )
{
unsigned y = ( x * 2 ) + 1;
return quickBinaryToFloat( y );
}
[ wrong-code generated ]
$ i486-gnu-linux-g++ bin2float.cpp -Wall -O2 -c -fomit-frame-pointer -m32
00000000 <foo(unsigned int)>:
0: 83 ec 10 sub $0x10,%esp
3: d9 44 24 0c flds 0xc(%esp)
7: 83 c4 10 add $0x10,%esp
a: c3 ret
[ correct code generated ]
$ i486-gnu-linux-g++ bin2float.cpp -Wall -O2 -c -fomit-frame-pointer -m32 \
-fno-strict-aliasing
00000000 <foo(unsigned int)>:
0: 83 ec 10 sub $0x10,%esp
3: 8b 44 24 14 mov 0x14(%esp),%eax
7: 8d 44 00 01 lea 0x1(%eax,%eax,1),%eax
b: 89 44 24 0c mov %eax,0xc(%esp)
f: d9 44 24 0c flds 0xc(%esp)
13: 83 c4 10 add $0x10,%esp
16: c3 ret
--
Summary: wrong code or aliasing violation with missed diagnostic?
Product: gcc
Version: 4.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: pluto at agmk dot net
GCC build triplet: i486-linux
GCC host triplet: i486-linux
GCC target triplet: i486-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27417
