On 01/14/15 15:31, Jiong Wang wrote:
agree, and I think the truncation is needed otherwise there may have ICE
on some target.
and I found current gcc LOCATION info is very good !
have done an experimental hack on at "expand_assignment": 4931 where the
tree is expanded,
gcc could give quite useful & accurate warning based on tree LOCATION info.
./cc1 -O2 -mbig-endian pr48335-2.c
pr48335-2.c: In function ‘f5’:
pr48335-2.c:19:29: warning: overflow here !
((U *)((char *) &s.d + 1))[3] = x;
^
while we need to add warning at store_bit_field_using_insv where
there is no accurate LOCATION info. but looks like it's acceptable?
pr48335-2.c:19:33: warning: overflow here !
((U *)((char *) &s.d + 1))[3] = x;
^
Yes, I think we're on the right track now -- warn and truncate the the
insertion.
I just scanned our set of warning flags to see if this would fit nicely
under any of the existing flags, and it doesn't. I guess putting it
under -Wextra is probably best for now.
I think the warning text should indicate that the statement will write
outside the bounds of the destination object or something along those lines.
Jeff
