On 12/3/23 05:13, Richard Sandiford wrote:
[Gah. In my head I'd sent this a few weeks ago, but it turns out
that I hadn't even got to the stage of writing the changlog...]
LRA keeps track of the biggest mode for both hard registers and
pseudos. The updates assume that the modes are ordered, i.e. that
we can tell whether one is no bigger than the other at compile time.
That is (or at least seemed to be) a reasonable restriction for pseudos.
But it isn't necessarily so for hard registers, since the uses of hard
registers can be logically distinct. The testcase is an example of this.
The biggest mode of hard registers is also special for other reasons.
As the existing comment says:
/* A reg can have a biggest_mode of VOIDmode if it was only ever seen as
part of a multi-word register. In that case, just use the reg_rtx
mode. Do the same also if the biggest mode was larger than a register
or we can not compare the modes. Otherwise, limit the size to that of
the biggest access in the function or to the natural mode at least. */
This patch applies the same approach to the updates.
Tested on aarch64-linus-gnu (with and without SVE) and on x86_64-linux-gnu.
OK to install?
Sure. Thank you for fixing this, Richard.
