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From: "enkovich.gnu at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/50037] Unroll factor exceeds max trip count
Date: Wed, 10 Aug 2011 15:33:00 -0000	[thread overview]
Message-ID: <bug-50037-4-kIIW1Ov74o@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-50037-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50037

--- Comment #2 from Ilya Enkovich <enkovich.gnu at gmail dot com> 2011-08-10 15:33:22 UTC ---
I wouldn't blame vectorizer here. Following loop is unrolled with unroll factor
8 even if vectorizer is disabled:

for ( count = ((*(hdrptr)) & 0x3) * 2; count > 0; count--, addr++ )
    sum += *addr;

BTW prologue loops generated by vectorizer also compute iterations count using
'AND' expression. Therefore we may frequently get prologue loops unrolled which
is never profitable if we use such huge unroll factor.


  parent reply	other threads:[~2011-08-10 15:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-10 14:44 [Bug rtl-optimization/50037] New: " enkovich.gnu at gmail dot com
2011-08-10 15:14 ` [Bug rtl-optimization/50037] " rguenth at gcc dot gnu.org
2011-08-10 15:33 ` enkovich.gnu at gmail dot com [this message]
2011-08-10 15:42 ` rguenth at gcc dot gnu.org
2011-08-10 16:57 ` matz at gcc dot gnu.org
2011-08-11 11:23 ` rguenth at gcc dot gnu.org
2011-08-11 11:41 ` rguenth at gcc dot gnu.org
2011-08-11 12:14 ` rguenth at gcc dot gnu.org
2011-08-15  9:12 ` enkovich.gnu at gmail dot com
2021-12-18 23:15 ` pinskia at gcc dot gnu.org

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