If the phi moves are the same for all predecessors, the move optimizer
will merge them by picking an arbitrary move among them,
moving it to the phi's block, and eliminating the moves in the
predecessor blocks.
However, phi inputs may have different width, and this can result in a
mismatch between the source and destination representation.
Always emit gap moves based on the destination operand's
representation, to ensure that in this case the wider phi inputs are not
truncated.
R=tebbi@chromium.orgCC=dmercadier@chromium.org
Bug: chromium:1407571
Change-Id: I0263cd5024e8e1340fb971267b133a2a91090f8f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4178824
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85403}
0bfae5d165