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From: "bonzini at gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/39715] [4.5 Regression][cond-optab] extra sign extensions on Thumb
Date: Tue, 14 Jul 2009 10:51:00 -0000 [thread overview]
Message-ID: <20090714105131.4495.qmail@sourceware.org> (raw)
In-Reply-To: <bug-39715-7849@http.gcc.gnu.org/bugzilla/>
------- Comment #2 from bonzini at gnu dot org 2009-07-14 10:51 -------
Here combine simplifies the zero extension from
(lshiftrt:SI (ashift:SI (subreg:SI (reg:QI 138) 0)
(const_int 24 [0x18]))
(const_int 24 [0x18]))
to (ne:SI (subreg:SI (reg:QI 138)). From there it cannot derive anymore that
nonzero_bits of the operand is 1 and thus the NE is redundant.
But shouldn't the subreg actually be a ZERO_EXTEND?
--
bonzini at gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rsandifo at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39715
next prev parent reply other threads:[~2009-07-14 10:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-10 12:44 [Bug target/39715] New: [cond-optab] " bonzini at gnu dot org
2009-05-12 12:05 ` [Bug target/39715] [4.5 Regression][cond-optab] " bonzini at gnu dot org
2009-05-21 10:36 ` rguenth at gcc dot gnu dot org
2009-05-21 10:49 ` rearnsha at gcc dot gnu dot org
2009-07-14 10:51 ` bonzini at gnu dot org [this message]
2009-07-14 12:56 ` bonzini at gnu dot org
2009-07-14 22:42 ` bonzini at gnu dot org
2009-10-28 10:27 ` bonzini at gcc dot gnu dot org
2009-10-28 10:44 ` bonzini at gnu dot org
2009-10-28 16:44 ` bonzini at gcc dot gnu dot org
2009-10-28 16:47 ` bonzini at gnu dot org
2009-10-29 16:52 ` law at gcc dot gnu dot org
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