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From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: java-prs@gcc.gnu.org
Subject: [Bug java/17731] sub-optimal code generated for left shift
Date: Wed, 29 Sep 2004 18:11:00 -0000	[thread overview]
Message-ID: <20040929181107.5174.qmail@sourceware.org> (raw)
In-Reply-To: <20040929175802.17731.tromey@gcc.gnu.org>


------- Additional Comments From pinskia at gcc dot gnu dot org  2004-09-29 18:11 -------
on PPC:
__ZN4test5shiftEii:
        rlwinm r5,r5,0,27,31
        slw r3,r4,r5
        blr

Which is correct as r5 could be greater than 31 and being greater than 31 is undefined (4 bits are only 
used really but it could do something different than that).

So if this were to be done correctly, we would need a target hook for the Java front-end.

Note the only reason why I bring this up is because we just had a bootstrap failure where we depended 
on being anded by the machine and not in the code.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17731


  parent reply	other threads:[~2004-09-29 18:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-29 17:58 [Bug java/17731] New: " tromey at gcc dot gnu dot org
2004-09-29 18:05 ` [Bug java/17731] " pinskia at gcc dot gnu dot org
2004-09-29 18:09 ` tromey at gcc dot gnu dot org
2004-09-29 18:11 ` pinskia at gcc dot gnu dot org [this message]
2004-09-29 18:14 ` [Bug target/17731] " pinskia at gcc dot gnu dot org
2004-09-29 18:16 ` pinskia at gcc dot gnu dot org
2004-09-29 19:39 ` [Bug rtl-optimization/17731] " rth at gcc dot gnu dot org
2004-09-29 21:03 ` tromey at gcc dot gnu dot org

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