From: Richard Henderson <rth@twiddle.net>
To: Aurelien Jarno <aurelien@aurel32.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 4/7] tcg: Optimize double-word comparisons against zero
Date: Mon, 01 Oct 2012 11:47:15 -0700 [thread overview]
Message-ID: <5069E533.2030307@twiddle.net> (raw)
In-Reply-To: <20121001184356.GB4623@ohm.aurel32.net>
On 2012-10-01 11:43, Aurelien Jarno wrote:
> While it's a nice optimization to have, one that seems to happen a lot
> more often is the two high parts being equal. It happens when the guest
> is working on (u)int32_t.
It depends on what target you're looking at. For alpha guest, all branches
are comparisons vs zero, so LT/GE happens with some regularity.
r~
next prev parent reply other threads:[~2012-10-01 18:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 17:19 [Qemu-devel] [PATCH 0/7] Double-word tcg/optimize improvements Richard Henderson
2012-09-27 17:19 ` [Qemu-devel] [PATCH 1/7] tcg: Split out swap_commutative as a subroutine Richard Henderson
2012-09-27 21:45 ` Aurelien Jarno
2012-09-27 17:19 ` [Qemu-devel] [PATCH 2/7] tcg: Optimize add2 + sub2 Richard Henderson
2012-09-27 23:20 ` Aurelien Jarno
2012-09-27 23:28 ` Richard Henderson
2012-10-01 17:46 ` Aurelien Jarno
2012-10-01 18:41 ` Richard Henderson
2012-09-30 7:04 ` Blue Swirl
2012-10-01 18:36 ` Richard Henderson
2012-09-27 17:19 ` [Qemu-devel] [PATCH 3/7] tcg: Swap commutative double-word comparisons Richard Henderson
2012-09-27 23:22 ` Aurelien Jarno
2012-09-27 17:19 ` [Qemu-devel] [PATCH 4/7] tcg: Optimize double-word comparisons against zero Richard Henderson
2012-10-01 18:43 ` Aurelien Jarno
2012-10-01 18:47 ` Richard Henderson [this message]
2012-09-27 17:19 ` [Qemu-devel] [PATCH 5/7] tcg: Split out subroutines from do_constant_folding_cond Richard Henderson
2012-10-01 18:46 ` Aurelien Jarno
2012-09-27 17:19 ` [Qemu-devel] [PATCH 6/7] tcg: Tidy brcond optimization Richard Henderson
2012-10-01 18:48 ` Aurelien Jarno
2012-09-27 17:19 ` [Qemu-devel] [PATCH 7/7] tcg: Do constant folding on double-word comparisons Richard Henderson
2012-10-01 18:50 ` Aurelien Jarno
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