This patch adds a partial_subreg_p predicate to go alongside
paradoxical_subreg_p.
Like the paradoxical_subreg_p patch, this one replaces some tests that
were based on GET_MODE_SIZE rather than GET_MODE_PRECISION. In each
case the change should be a no-op or an improvement.
The regcprop.c patch prevents some replacements of the 82-bit RFmode
with the 80-bit XFmode on ia64. I don't understand the target details
here particularly well, but from the way the modes are described in
ia64-modes.def, it isn't valid to assume that an XFmode can carry an
RFmode payload. A comparison of the testsuite assembly output for one
target per CPU showed no other differences.
Some of the places changed here are tracking the widest access mode
found for a register. The series tries to standardise on:
if (partial_subreg_p (widest_seen, new_mode))
widest_seen = new_mode;
rather than:
if (paradoxical_subreg_p (new_mode, widest_seen))
widest_seen = new_mode;
Either would have been OK.
2017-08-30 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>