On 1/8/24 09:57, Andrew Pinski wrote:
On Mon, Jan 8, 2024 at 6:44 AM Uros Bizjak <ubiz...@gmail.com> wrote:
Instead of converting XOR or PLUS of two values, ANDed with two constants that
have no bits in common, to IOR expression, convert IOR or XOR of said two
ANDed values to PLUS expression.
I think this only helps targets which have leal like instruction. Also
I think it is the same issue as I recorded as PR 111763 . I suspect
BIT_IOR is more of a Canonical form for GIMPLE while we should handle
this in expand to decide if we want to use PLUS or IOR.
Actually there's benefit on RISC-V to using PLUS over IOR/XOR when
there's no bits in common. In fact, I've been asked to do that by
Andrew W. for a case where we know ahead of time there's no bits in
common in a sequence that currently uses IOR.
Specifically it can allow more use of the compact instructions as the
compact PLUS allows the full set of hard registers while compact IOR/XOR
only allow a subset of registers.
jeff
