Re: lib/50887: __clzdi2 implementation in compile_rt incompatible with gcc

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR lib/50887; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: Joerg Sonnenberger <joerg%britannica.bec.de@localhost>
Cc: gnats-bugs%NetBSD.org@localhost
Subject: Re: lib/50887: __clzdi2 implementation in compile_rt incompatible with gcc
Date: Fri, 4 Mar 2016 12:47:50 +0100

 On Thu, Mar 03, 2016 at 11:17:26AM +0100, Joerg Sonnenberger wrote:
 > I can't find any sensible reason for the GCC behavior. Even when using
 > the table version, it is better to only four lookups instead of eight,
 > so this is really something where GCC should be fixed to match its own
 > builtin definition.
 
 I asked Eric Botcazou and he said:
 
   That's the default behavior for clz and clrsb though: no libgcc routine for
   subword operation and fallback to the word-sized routine if no instruction.
 
 so we would have to fix quite a few gcc targets and have issues feeding
 this change back upstream (I suppose).
 
 Martin