On Thu, Sep 11, 2025 at 07:14:51PM +0200, Richard Biener wrote:
> Yes, RTL expansion inserts an AND operation when !SHIFT_COUNT_TRUNCATED.
> What I was saying there's no way to get a negative shift count flip shift
> direction to RTL - it would require a target specific intrinsic that's a
> builtin
> call before RTL expansion and an UNSPEC after.
Of course the target can have patterns like:
(set (match_operand:M 0)
(if_then_else:M
(lt:SI (match_operand:SI 2) (const_int 0))
(ashiftrt:M (match_operand:M 1) (neg:SI (match_dup 2)))
(ashift:M (match_dup 1) (match_dup 2))))
or so, it doesn't need to use UNSPEC for that.
Jakub
