Re: [PATCH] simplify-rtx.cc:Simplify XOR(AND(ROTATE(~1), A), ASHIFT(1, A)) to IOR

[Jeff Law]

On 6/12/25 1:57 AM, Richard Sandiford wrote:

It's probably best to be safe, though it'd be a real surprise to see the
shift count being truncated on a shift, but not on a rotate or vice-versa

I was thinking that a rotate kind-of has to be truncating, since it
isn't really a rotation if it drops bits from first operand.  But 1<<A
could easily get shifted to zero if A isn't truncated.
That was the case I was most concerned with and the primary reason why I 
leaned towards adding the check.

Jeff