If compiled with gcc -c -Wconversion the following code produces the warning:
test.c:7: warning: conversion to short int from int may alter its value
but if -DNO_WARNING is turned on it doesn't even though it should be same code.
cat > test.c <<EOF
short mask(short x)
{
#if NO_WARNING
short y = 0x7fff;
return x&y;
#else
return x & (short)0x7fff;
#endif
}
EOF
On a side node, I think it would be better to also change the warning to :
"conversion from 'int' to 'short int' may alter its value", which i find easier
to read.
--
Summary: -Wconversion produces wrong warning
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: Raimund dot Merkert at baesystems dot com
GCC target triplet: gcc (GCC) 4.3.0 20071130 (experimental)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34389
