On Thu, Jan 29, 2015 at 11:39 AM, Jakub Jelinek <ja...@redhat.com> wrote: > On Thu, Jan 29, 2015 at 06:27:36PM +0800, Thomas Preud'homme wrote: >> Incorrect folding happen when a bitfield in a union is accessed and the >> union was initialized via another field. This is a reminiscence of >> GCC32RM-325 due to sccvn not passing the right size to fold_ctor_reference. >> sccvn uses TYPE_SIZE which gives the size of the container integer for a >> bitfield instead of TYPE_PRECISION that gives the actual size occupied by >> the bitfield. This patch fixes that and modify bitfld-6 so that it catch >> this issue in addition to the old one. >> >> ChangeLog entries are as follows: >> >> *** gcc/ChangeLog *** >> >> 2015-01-28 Thomas Preud'homme <thomas.preudho...@arm.com> >> > > You should mention > PR middle-end/62103 > I'll defer review of the sccvn change to Richard. > >> * tree-ssa-sccvn.c (fully_constant_vn_reference_p): Use >> TYPE_PRECISION >> to compute size of referenced value in the constant case. >> >> *** gcc/testsuite/ChangeLog *** >> >> 2015-01-28 Thomas Preud'homme <thomas.preudho...@arm.com> >> >> * gcc.c-torture/execute/bitfld-6.c: Use 24 bits for bitfield b. >> Adapt >> expected values accordingly. > > IMHO if the old testcase wasn't incorrect, you'd better add a new testcase > instead of modifying existing one.
Yeah - please add a new testcase. The patch is otherwise ok. Thanks, Richard. > Jakub
