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Re: [PATCH] Fix PR middle-end/28690, indexed load/store performance + reload bug
- From: "Ulrich Weigand" <uweigand at de dot ibm dot com>
- To: bergner at vnet dot ibm dot com (Peter Bergner)
- Cc: matz at suse dot de (Michael Matz), pinskia at gmail dot com (Andrew Pinski), gcc-patches at gcc dot gnu dot org
- Date: Mon, 11 Dec 2006 18:37:54 +0100 (CET)
- Subject: Re: [PATCH] Fix PR middle-end/28690, indexed load/store performance + reload bug
Peter Bergner wrote:
> In this case, the first "find_reg (allocno_order[i], 0, 0, 0, 0)" fails to
> find a register, so we're forced to find a register in an alternate class.
> For pseudo 238, reg_alternate_class() returns ALL_REGS, so we call
> "find_reg (allocno_order[i], 0, 1, 0, 0)" and it's this call that we get
> reg 65. I'll dig in a little more to see why we didn't get a reg during
> the first call to find_reg.
That will most likely be simply because all registers in that class are
already in use.
The interesting question is, why is reg_alternate_class for the pseudo
ALL_REGS if there's an instruction that doesn't accept it ...
Dr. Ulrich Weigand
GNU Toolchain for Linux on System z and Cell BE