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From: "olegendo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/53987] [SH] Unnecessary zero-extensions
Date: Sat, 01 Aug 2015 09:57:00 -0000	[thread overview]
Message-ID: <bug-53987-4-plj6918ndS@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53987-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53987

--- Comment #12 from Oleg Endo <olegendo at gcc dot gnu.org> ---
The following case:

int
fun_01 (char* x, char* y, int z)
{
  return ((x[1] & x[2] & x[3]) == 0) + z;
}

results in:
        add     #1,r4
        mov.b   @r4+,r2
        mov     #0,r0
        mov.b   @r4+,r1
        and     r2,r1
        mov.b   @r4+,r2
        extu.b  r1,r1     <<< unnecessary
        tst     r2,r1
        rts     
        addc    r6,r0

The tstsi_t splitter has some code to eliminate some sign/zero extensions but
it doesn't see through the and/or/xor insns.  Maybe it's better to a separate
pass that optimizes sign/zero extensions instead of adding more clutter to the
splitters.


  parent reply	other threads:[~2015-08-01  9:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-16 23:50 [Bug target/53987] New: [SH] Unnecessary zero-extension before cmp/eq olegendo at gcc dot gnu.org
2012-08-31 18:14 ` [Bug target/53987] " olegendo at gcc dot gnu.org
2013-10-29 21:58 ` olegendo at gcc dot gnu.org
2013-12-16 19:07 ` olegendo at gcc dot gnu.org
2014-12-17 21:09 ` olegendo at gcc dot gnu.org
2014-12-21 16:54 ` [Bug target/53987] [SH] Unnecessary zero-extensions olegendo at gcc dot gnu.org
2014-12-22 22:27 ` olegendo at gcc dot gnu.org
2014-12-25  1:11 ` olegendo at gcc dot gnu.org
2014-12-30 17:26 ` olegendo at gcc dot gnu.org
2015-01-15  1:37 ` olegendo at gcc dot gnu.org
2015-01-24 13:06 ` olegendo at gcc dot gnu.org
2015-01-27 23:08 ` olegendo at gcc dot gnu.org
2015-08-01  9:57 ` olegendo at gcc dot gnu.org [this message]
2015-09-09 12:15 ` olegendo at gcc dot gnu.org

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