http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53104
Bug #: 53104
Summary: convert_move on MODE_PARTIAL_INT does not look for
existing conversion
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: big...@acm.org
convert_move has special code to handle conversion to and from
MODE_PARTIAL_INT. Above this code is a comment stating that targets are
expected to provide conversion insns for the MODE_PARTIAL_INT modes they
use.
When presented with a move from HImode to PSImode, however, this code will
unconditionally convert HImode to SImode, then truncate back down to
PSImode. For cases where both these operations are fairly expensive, it
should instead first check to see whether the target provided the desired
conversion directly.
