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Re: [PATCH, rs6000] Switch the rs6000 port over to LRA
- From: Peter Bergner <bergner at vnet dot ibm dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Segher Boessenkool <segher at kernel dot crashing dot org>, David Edelsohn <dje dot gcc at gmail dot com>, Michael Meissner <meissner at linux dot vnet dot ibm dot com>, Bill Schmidt <wschmidt at linux dot vnet dot ibm dot com>, Peter Bergner <bergner at vnet dot ibm dot com>
- Date: Wed, 3 Aug 2016 17:59:17 -0500
- Subject: Re: [PATCH, rs6000] Switch the rs6000 port over to LRA
- Authentication-results: sourceware.org; auth=none
- References: <d4245e94-6a1e-93ad-0d13-8eb016f04029@bergner.org>
On 8/2/16 3:17 PM, Peter Bergner wrote:
Now that Vlad has fixed PR69847, which was the last problem holding the
rs6000 port from switching from reload to LRA, we are ready to flip the
switch.
Is the following ok once bootstrap/regtesting on both LE and BE
(32 & 64 regtesting) comes out clean?
So we have two "regressions":
+FAIL: gcc.target/powerpc/bool3-p7.c scan-assembler-not [ \\t]xxlnor
+FAIL: gcc.target/powerpc/bool3-p8.c scan-assembler-not [ \\t]xxlnor
Looking into these "failures", they show up because when we enable
LRA, we also implicitly enable -mvsx-timode and these failures are
due to -mvsx-timode. The same test cases fail when we use -mvsx-timode
with reload.
I'll note that these failures are not code correctness bugs, but
performance bugs. I plan to open a bugzilla to track the fixing
of these failures.
My question, is since these failures are not due to LRA, do we
want to consider the switch to LRA ok to commit or do we want to
wait until the -mvsx-timode performance bug is fixed?
Peter