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Re: [PATCH] fix prefetch optimization in loop.c
- From: Richard Henderson <rth at redhat dot com>
- To: Janis Johnson <janis187 at us dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 21 Jan 2002 16:20:47 -0800
- Subject: Re: [PATCH] fix prefetch optimization in loop.c
- References: <20020121111114.C1890@us.ibm.com>
On Mon, Jan 21, 2002 at 11:11:14AM -0800, Janis Johnson wrote:
> This patch allows the mainline to bootstrap on i686-pc-linux-gnu with
> BOOT_CFLAGS="-O2 -fprefetch-loop-arrays -mcpu=pentium3". Without this
> patch, reload.c and reload1.c were being miscompiled when loops were
> considered and then rejected for prefetch optimization. This happened
> because of an assumption that rtx_copy was returning a copy of the
> address rtx when it was actually returning a pointer to the original
> rtx.
Um, the only cases in which a copy is not created is bare
registers and bare constants. Why would this cause a problem?
r~