Hi, Extracting a bitfield from a vector can be achieved by casting the vector to a new type whose elements are the same size as the desired bitfield, before generating a subreg. However, this is only an optimization if the original vector can be accessed in the new machine mode without first being copied - a condition denoted by the TARGET_MODES_TIEABLE_P hook.
This patch adds a check to make sure that the vector modes are
tieable before attempting to generate a subreg. This is a necessary
prerequisite for a subsequent patch that will introduce new machine
modes for Arm Neon vector-tuple types.
Bootstrapped and regression tested on aarch64-none-linux-gnu and
x86_64-pc-linux-gnu - no issues.
Ok for master?
Thanks,
Jonathan
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gcc/ChangeLog:
2021-10-11 Jonathan Wright <jonathan.wri...@arm.com>
* expmed.c (extract_bit_field_1): Ensure modes are tieable.
rb14926.patch
Description: rb14926.patch
