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Re: [PATCH 1/6] rs6000: Remove "O" alternative from lshrsi3
- From: David Edelsohn <dje dot gcc at gmail dot com>
- To: Segher Boessenkool <segher at kernel dot crashing dot org>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Sun, 22 Jun 2014 10:56:44 -0400
- Subject: Re: [PATCH 1/6] rs6000: Remove "O" alternative from lshrsi3
- Authentication-results: sourceware.org; auth=none
- References: <7e27608c0046f8b5d09895bd504ab07abb80ee15 dot 1403400402 dot git dot segher at kernel dot crashing dot org>
On Sat, Jun 21, 2014 at 10:46 PM, Segher Boessenkool
<segher@kernel.crashing.org> wrote:
> Nothing will ever generate RTL matching this alternative. Maybe long
> ago this was needed, but not anymore.
Can you provide some reference for that assertion?
At some point GCC created shifts with zero shift count. It probably
does not, but does a generic optimization prevent this?
Thanks, David