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[Bug tree-optimization/19686] [4.0 Regression] loop performance decrease, not comparing against 0
- From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 30 Jan 2005 19:53:03 -0000
- Subject: [Bug tree-optimization/19686] [4.0 Regression] loop performance decrease, not comparing against 0
- References: <20050129065037.19686.dmixm@marine.febras.ru>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-01-30 19:52 -------
Actually the conversion to unsigned is free. The problem is something different.
The problem is that we are no longer comparing against 0 instead we are comparing something totally
different.
(ivtmp.2 != (unsigned int) (x - 1) * 65535 + 65535)
--
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |minor
Status|UNCONFIRMED |NEW
Component|target |tree-optimization
Ever Confirmed| |1
Keywords| |missed-optimization
Last reconfirmed|0000-00-00 00:00:00 |2005-01-30 19:53:00
date| |
Summary|avr-gcc 4.0: loop |[4.0 Regression] loop
|performance decrease (extra |performance decrease, not
|conversion) |comparing against 0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19686