Re: [PATCH 04/13] arm: Add GENERAL_AND_VPR_REGS regclass

[Christophe LYON via Gcc-patches]

On 28/09/2021 13:18, Kyrylo Tkachov wrote:
Hi Christophe,

-----Original Message-----
From: Gcc-patches <gcc-patches-
bounces+kyrylo.tkachov=arm....@gcc.gnu.org> On Behalf Of Christophe
LYON via Gcc-patches
Sent: 08 September 2021 08:49
To: Richard Earnshaw <richard.earns...@foss.arm.com>; gcc-
patc...@gcc.gnu.org
Subject: Re: [PATCH 04/13] arm: Add GENERAL_AND_VPR_REGS regclass


On 07/09/2021 15:35, Richard Earnshaw wrote:

On 07/09/2021 13:05, Christophe LYON wrote:
On 07/09/2021 11:42, Richard Earnshaw wrote:

On 07/09/2021 10:15, Christophe Lyon via Gcc-patches wrote:
At some point during the development of this patch series, it appeared
that in some cases the register allocator wants “VPR or general”
rather than “VPR or general or FP” (which is the same thing as
ALL_REGS).  The series does not seem to require this anymore, but it
seems to be a good thing to do anyway, to give the register allocator
more freedom.

2021-09-01  Christophe Lyon <christophe.l...@foss.st.com>

     gcc/
     * config/arm/arm.h (reg_class): Add GENERAL_AND_VPR_REGS.
     (REG_CLASS_NAMES): Likewise.
     (REG_CLASS_CONTENTS): Likewise. Add VPR_REG to ALL_REGS.

diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 015299c1534..fab39d05916 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1286,6 +1286,7 @@ enum reg_class
     SFP_REG,
     AFP_REG,
     VPR_REG,
+  GENERAL_AND_VPR_REGS,
     ALL_REGS,
     LIM_REG_CLASSES
   };
@@ -1315,6 +1316,7 @@ enum reg_class
     "SFP_REG",        \
     "AFP_REG",        \
     "VPR_REG",        \
+  "GENERAL_AND_VPR_REGS", \
     "ALL_REGS"        \
   }
   @@ -1343,7 +1345,8 @@ enum reg_class
     { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG
*/    \
     { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG
*/    \
     { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.
*/    \
-  { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000000F }  /* ALL_REGS.
*/    \
+  { 0x00005FFF, 0x00000000, 0x00000000, 0x00000400 }, /*
GENERAL_AND_VPR_REGS.  */ \
+  { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000040F }  /* ALL_REGS.
*/    \
   }
You've changed the definition of ALL_REGS here (to include VPR_REG),
but not really explained why.  Is that the source of the underlying
issue with the 'appeared' you mention?

I first added VPR_REG to ALL_REGS, but Richard Sandiford suggested I
create a new GENERAL_AND_VPR_REGS that would be more restrictive. I
did not remove VPR_REG from ALL_REGS because I thought it was an
omission: shouldn't ALL_REGS contain all registers?
Surely that should be a separate patch then.
OK, I can remove that line from this patch and make a separate one-liner
for ALL_REGS.
Did you end up sending that patch out? (Sorry, I may have missed it in my 
archive).
This patch to add GENERAL_AND_VPR_REGS is okay with the ALL_REGS change 
separated out.

No I didn't send it yet: I suspect there will be iterations on the next 
patches in the series, this small change alone wasn't worth sending a v2 :-)

Thanks,

Christophe



Thanks,
Kyrill

Thanks,

Christophe


R.


R.


     #define FP_SYSREGS \