Correct. It is truncated for integer shift, but not simd shift instructions. We
generate a pattern in the split that only generates the integer shift
From: Richard Kenner [mailto:ken...@vlsi1.ultra.nyu.edu]
Sent: Tuesday, August 8, 2017 1:04 PM
To: Michael Collison <michael.colli...@arm.com>
Cc: email@example.com; nd <n...@arm.com>; pins...@gmail.com
Subject: RE: [PATCH] [Aarch64] Optimize subtract in shift counts
> Because for integer shift instructions the shift count is truncated.
> We ensure that we only use integer shift instructions by emitting a
> shift with a mask. This only matches integer shift instructions in the
> md file.
That's why I asked about SHIFT_COUNT_TRUNCATED. So it's truncated for some
shifts, but not all?