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Re: IF conversion bug with CC0
- From: Jeff Law <law at redhat dot com>
- To: Eric Botcazou <ebotcazou at adacore dot com>
- Cc: gcc at gcc dot gnu dot org, dgisselq at ieee dot org
- Date: Mon, 4 Apr 2016 16:32:28 -0600
- Subject: Re: IF conversion bug with CC0
- Authentication-results: sourceware.org; auth=none
- References: <1459801150 dot 1603 dot 51 dot camel at jericho> <1459804405 dot 1603 dot 55 dot camel at jericho> <5702DBDB dot 7080102 at redhat dot com> <1752525 dot tYkN1d13DP at polaris>
On 04/04/2016 04:20 PM, Eric Botcazou wrote:
From a 30 second view of your ISA, it appears that most
arithmetic/logicals unconditionally set the condition codes.
I would suggest modeling condition code handling similar to how it's
done on the x86 port.
No advertisement intended, but the Visium architecture is the typical 32-bit
RISC where every single arithmetic/logical unconditionally sets the condition
code. Moreover, the port was very recently converted from CC0 to CCmode (with
uniform post-reload splitters and define_substs tailored for the postreload
compare elimination pass), so it could be a good model.
Visium might be an easier port to read/understand :-)