gnupic: sdcc bug
Subject:
Re: sdcc bug
From:
Samuel Tardieu ####@####.####
Date:
14 Oct 2002 20:17:58 -0000
Message-Id: <2002-10-14-22-14-45+trackit+sam@rfc1149.net>
Your post reminded me that I wanted to look at SDCC for a long
time. While reading the source, I noticed the latest peephole
optimization:
replace restart {
movf %1,w
movwf %1
} by {
; peep 11 - Removed redundant move
movf %1,w
}
This optimization looks dangerous to me in at least two situations:
- one wants to mirror the perceived state of a port in
high-impedance mode (portb = portb)
- one wants to act on a timer by having it loose four instruction
cycles (tmr0 = tmr0 will do that)
What kind of C code could produce such a pattern which needs to be
optimized?
Sam
--
Samuel Tardieu -- ####@####.#### -- http://www.rfc1149.net/sam
