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Re: -march prescott: GENERAL_REGS error; but -msseX Ok ?
- From: "sean darcy" <seandarcy at hotmail dot com>
- To: falk at debian dot org
- Cc: gcc at gcc dot gnu dot org
- Date: Sun, 30 Jan 2005 11:59:29 -0500
- Subject: Re: -march prescott: GENERAL_REGS error; but -msseX Ok ?
- Bcc:
----Original Message Follows----
From: Falk Hueffner
................
So is the only reason prescott doesn't work is prefetch-sse.
No, that is a red herring. The different instruction scheduling causes
the register allocator to randomly fail or not.
I don't know what you mean by random, but I just tried to build mythtv 10
times with each set of cflags. The set with -mtune=prescott always bombed,
the other always worked.
So what does mtune cause gcc to do that the other set of cflags doesn't? How
does mtune change the instruction scheduling if it's not in config/i386.c?
There's no way for us
to fix this reliably, the asm must be changed to constrain the
register allocator less.
Yeh. I read the list.
sean