Commit Graph

9 Commits

Author SHA1 Message Date
Craig Topper 41ff1e0e29 [RISCV] Improve register allocation for masked vwadd(u).wv, vwsub(u).wv, vfwadd.wv, and vfwsub.wv.
The first source has the same EEW as the destination, but we're
using earlyclobber which prevents them from ever being the same
register.

To workaround this, add a special TIED pseudo to use whenever the
first source and merge operand are the same value. This allows
us to use a single operand for the merge operand and first source
which we can then tie to the destination. A tied source disables
earlyclobber for that operand.

Reviewed By: arcbbb

Differential Revision: https://reviews.llvm.org/D103211
2021-06-01 18:59:00 -07:00
Craig Topper a41309966a [RISCV] Pre-commit test cases for D103211. NFC 2021-05-28 13:21:58 -07:00
Craig Topper fdf10e6197 [RISCV] Use X0 as destination of inserted vsetvli when possible.
We aren't going to connect the result to anything so we might
as well avoid allocating a register.

Reviewed By: frasercrmck, HsiangKai

Differential Revision: https://reviews.llvm.org/D102031
2021-05-26 13:08:51 -07:00
Jessica Clarke d63d662d3c [RISCV] Remove --riscv-no-aliases from RVV tests
This serves no useful purpose other than to clutter things up. Diff
summary as the real diff is extremely unwieldy:

   24844 -; CHECK-NEXT:    jalr zero, 0(ra)
   24844 +; CHECK-NEXT:    ret
       8 -; CHECK-NEXT:    vl4re8.v v28, (a0)
       8 +; CHECK-NEXT:    vl4r.v v28, (a0)
      64 -; CHECK-NEXT:    vl8re8.v v24, (a0)
      64 +; CHECK-NEXT:    vl8r.v v24, (a0)
     392 -; RUN:   --riscv-no-aliases < %s | FileCheck %s
     392 +; RUN:   < %s | FileCheck %s
       1 -; RUN:   -verify-machineinstrs --riscv-no-aliases < %s \
       1 +; RUN:   -verify-machineinstrs < %s \

As discussed in D103004.
2021-05-26 17:59:38 +01:00
Craig Topper 3ae71226ef [RISCV] Drop earlyclobber constraint from vwadd(u).wx, vwsub(u).wx, vfwadd.wf and vfwsub.wf.
The first source has the same EEW as the destination and the other
source is a scalar so the overlap constraints don't apply to
the unmasked version.

For the masked version we have a constraint that the destination
can't be V0 so that covers the only overlap issue there.

Reviewed By: khchen

Differential Revision: https://reviews.llvm.org/D100217
2021-04-11 10:19:45 -07:00
Hsiangkai Wang a2d19bad07 [RISCV] Use whole register load/store for generic load/store.
In vector v0.10, there are whole vector register load/store
instructions. I suggest to use the whole register load/store
instructions for generic load/store for scalable vector types. It could
save up vset{i}vl{i} for these load/store.

For fractional LMUL, I keep to use vle{eew}.v/vse{eew}.v instructions to
load/store partial vector registers.

Differential Revision: https://reviews.llvm.org/D95853
2021-02-09 15:52:04 +08:00
Hsiangkai Wang 6e360460f1 [RISCV] Use v8-v23 as argument registers to conform to the proposal.
The maximum LMUL is 8. We need 16 vector registers for two LMUL-8
arguments. The modification follows the proposal of psABI in
https://github.com/riscv/riscv-elf-psabi-doc/pull/171

Differential Revision: https://reviews.llvm.org/D95134
2021-01-22 07:55:24 +08:00
Craig Topper 79cbb003c5 [RISCV] Don't use tail agnostic policy on instructions where destination is tied to source
If the destination is tied, then user has some control of the
register used for input. They would have the ability to control
the value of any tail elements. By using tail agnostic we take
this option away from them.

Its not clear that the intrinsics are defined such that this isn't
supposed to work. And undisturbed is a valid implementation for agnostic
so code wouldn't even fail to work on all systems if we always used
agnostic.

The vcompress intrinsic is defined to require tail undisturbed so
at minimum we need this for that instruction or need to redefine
the intrinsic.

I've made an exception here for vmv.s.x/fmv.s.f and reduction
instructions which only write to element 0 regardless of the tail
policy. This allows us to keep the agnostic policy on those which
should allow better redundant vsetvli removal.

An enhancement would be to check for undef input and keep the
agnostic policy, but we don't have good test coverage for that yet.

Reviewed By: khchen

Differential Revision: https://reviews.llvm.org/D93878
2020-12-29 10:37:58 -08:00
Hsiangkai Wang db48a6de77 [RISCV] Define vwadd/vwaddu/vwsub/vwsubu intrinsics.
Define vwadd/vwaddu/vwsub/vwsubu intrinsics and lower to V instructions.

Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Hsiangkai Wang <kai.wang@sifive.com>

Differential Revision: https://reviews.llvm.org/D93108
2020-12-15 20:15:06 +08:00