Commit Graph

8 Commits

Author SHA1 Message Date
Stanislav Mekhanoshin 9a9a092e61 [AMDGPU] Avoid sorting stalls in regbank-reassign
This is the slowest operation in the already slow pass.
Instead of sorting just put a stall list into an ordered
map.

Differential Revision: https://reviews.llvm.org/D86253
2020-08-21 11:49:41 -07:00
Carl Ritson 57899934ea [AMDGPU] Make GCNRegBankReassign assign based on subreg banks
When scavenging consider the sub-register of the source operand
to determine the bank of a candidate register (not just sub0).
Without this it is possible to introduce an infinite loop,
e.g. $sgpr15_sgpr16_sgpr17 can be assigned for a conflict between
$sgpr0 and SGPR_96:sub1.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D84910
2020-08-04 12:54:44 +09:00
Christudasan Devadasan 375cec4b6c [AMDGPU] Introduce more scratch registers in the ABI.
The AMDGPU target has a convention that defined all VGPRs
(execept the initial 32 argument registers) as callee-saved.
This convention is not efficient always, esp. when the callee
requiring more registers, ended up emitting a large number of
spills, even though its caller requires only a few.

This patch revises the ABI by introducing more scratch registers
that a callee can freely use.
The 256 vgpr registers now become:
  32 argument registers
  112 scratch registers and
  112 callee saved registers.
The scratch registers and the CSRs are intermixed at regular
intervals (a split boundary of 8) to obtain a better occupancy.

Reviewers: arsenm, t-tye, rampitec, b-sumner, mjbedy, tpr

Reviewed By: arsenm, t-tye

Differential Revision: https://reviews.llvm.org/D76356
2020-05-05 23:02:58 +05:30
Stanislav Mekhanoshin 26777ad7a0 [AMDGPU] Adapt GCNRegBankReassign for 16 bit subregs
It allows it not to crash and analyze 16 bit subregs if those
appear in the instructions. At the same time it does not attempt
to reassign these. It still can correctly identify register
banks to let larger registers to be reassigned.

More work will be needed here when real instructions will use
these registers and more tests as well.

Differential Revision: https://reviews.llvm.org/D78772
2020-04-28 16:16:04 -07:00
Matt Arsenault 12994a70cf AMDGPU: Use SGPR_128 instead of SReg_128 for vregs
SGPR_128 only includes the real allocatable SGPRs, and SReg_128 adds
the additional non-allocatable TTMP registers. There's no point in
allocating SReg_128 vregs. This shrinks the size of the classes
regalloc needs to consider, which is usually good.

llvm-svn: 374284
2019-10-10 07:11:33 +00:00
Stanislav Mekhanoshin 7b5a54e369 [AMDGPU] Fixed occupancy calculation for gfx10
Differential Revision: https://reviews.llvm.org/D65010

llvm-svn: 366616
2019-07-19 21:29:51 +00:00
Stanislav Mekhanoshin 0846c125f9 [AMDGPU] gfx1010 core wave32 changes
Differential Revision: https://reviews.llvm.org/D63204

llvm-svn: 363934
2019-06-20 15:08:34 +00:00
Stanislav Mekhanoshin 3b7925f035 [AMDGPU] gfx1010 GCNRegBankReassign pass
Reassign registers to reduce register bank conflicts.

Differential Revision: https://reviews.llvm.org/D61344

llvm-svn: 359704
2019-05-01 16:49:31 +00:00