From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Edelsohn <dje@watson.ibm.com>
To: "David S. Miller" <davem@redhat.com>
Cc: dan@dberlin.org, austern@apple.com, gcc@gcc.gnu.org
Subject: Re: Faster compilation speed
Date: Tue, 13 Aug 2002 14:03:00 -0000
Message-id: <200208132103.RAA25968@makai.watson.ibm.com>
References: <20020813.103845.83626171.davem@redhat.com> <200208131749.NAA14432@makai.watson.ibm.com>
X-SW-Source: 2002-08/msg00779.html

	Here's an interesting (aka depressing) data point.  My previous
cache miss statistics were for GCC -O2.  At -O0, GCC's cache miss
statistics stay the same or get up to 20% *worse*.  In comparison, the
cache statistics for IBM's compiler without optimization enabled *improve*
up to 50 for the same reload.c and insn-recog.c input files compared to
optimized.

	GCC has some sort of overhead, maybe the tree->RTL conversion as
Dan mentioned, which really hurts re-use at -O0.

David