On 11/5/23 11:48, Richard Sandiford wrote:
An entity isn't transparent in a block that requires a specific mode.
optimize_mode_switching took that into account for normal insns,
but didn't for the exit block. Later patches misbehaved because
of this.
In contrast, an entity was correctly marked as non-transparent
in the entry block, but the reasoning seemed a bit convoluted.
It also referred to a function that no longer exists.
Since KILL = ~TRANSP, the entity is by definition not transparent
in a block that defines the entity, so I think we can make it so
without comment.
Finally, the exit handling was nested in the entry handling,
but that doesn't seem necessary. A target could say that an
entity is undefined on entry but must be defined on return,
on a "be liberal in what you accept, be conservative in what
you do" principle.
gcc/
* mode-switching.cc (optimize_mode_switching): Mark the exit
block as nontransparent if it requires a specific mode.
Handle the entry and exit mode as sibling rather than nested
concepts. Remove outdated comment.
OK
jeff
