[arm64] JIT: Recognize sbfiz/ubfiz idioms #61045
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
ghost
added
the
area-CodeGen-coreclr
|
Tagging subscribers to this area: @JulieLeeMSFT Issue DetailsThis PR recognizes '(ulong)x << cns' idioms in order to emit sbfiz/ubfiz. This patterns shows up in array accesses and while I am planning to fix array accesses in #61026 differently it still makes sense to have it. // explicit pattern:
static ulong Test1(uint x) => ((ulong)x) << 2;
// implicit pattern:
static int Test2(int[] array, int i) => array[i];Codegen diff: ; Method Prog:Test1(int):long
G_M16463_IG01:
stp fp, lr, [sp,#-16]!
mov fp, sp
G_M16463_IG02:
- mov w0, w0
- lsl x0, x0, #2
+ ubfiz x0, x0, #2, #32
G_M16463_IG03:
ldp fp, lr, [sp],#16
ret lr
-; Total bytes of code: 24
+; Total bytes of code: 20
; Method Prog:Test2(System.Int32[],int):int
G_M15622_IG01:
stp fp, lr, [sp,#-16]!
mov fp, sp
G_M15622_IG02:
ldr w2, [x0,#8]
cmp w1, w2
bhs G_M15622_IG04
- mov w1, w1
- lsl x1, x1, #2
+ ubfiz x1, x1, #2, #32
add x1, x1, #16
ldr w0, [x0, x1]
G_M15622_IG03:
ldp fp, lr, [sp],#16
ret lr
G_M15622_IG04:
bl CORINFO_HELP_RNGCHKFAIL
bkpt
-; Total bytes of code: 52
+; Total bytes of code: 48Diffs are impressive and gives us a hint we should implement proper "addressing modes" for arm64 asap 🙂 coreclr_tests.pmi.Linux.arm64.checked.mch:Detail diffslibraries.crossgen2.Linux.arm64.checked.mch:Detail diffslibraries.pmi.Linux.arm64.checked.mch:Detail diffslibraries_tests.pmi.Linux.arm64.checked.mch:Detail diffs
|
|
has most regressions. is there anything special about this pattern which disagrees with bfiz optimization? |
@kasperk81 it's loop-alignment artifacts, e.g. https://www.diffchecker.com/La4x8Sgz |
|
@SingleAccretion could you please take another look, I added smallint support (diffs are updated) and removed redundant checks. |
using System.Collections.Generic;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
public class Program
{
static void Main(string[] args) =>
BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);
public IEnumerable<object[]> TestData()
{
yield return new object[] { new int[100], new int[100] };
yield return new object[] { new int[1000], new int[1000] };
yield return new object[] { new int[100000], new int[100000] };
}
[Benchmark]
[ArgumentsSource(nameof(TestData))]
public void CopyArray(int[] src, int[] dst)
{
for (int i = 0; i < src.Length; i++)
dst[i] = src[i];
}
}Results on Apple M1 arm64: (tested with and without loop alignment) codegen diff: https://www.diffchecker.com/pLkuGMn6 (yes, address calculation is still not perfect and is not hoisted, but I work on it) |
SingleAccretion
approved these changes
Nov 1, 2021
|
@dotnet/jit-contrib PTAL, should be ready to review/merge |
BruceForstall
approved these changes
Nov 2, 2021
|
arm64 improvements: dotnet/perf-autofiling-issues#2247 and dotnet/perf-autofiling-issues#2248 |
This was referenced Nov 29, 2021
ghost
locked as resolved and limited conversation to collaborators
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
5 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR recognizes '(ulong)x << cns' idioms in order to emit sbfiz/ubfiz. This patterns shows up in array accesses and while I am planning to fix array accesses in #61026 differently it still makes sense to have this peephole for explicit patterns.
Example:
Codegen diff:
; Method Prog:Test1(int):long G_M16463_IG01: stp fp, lr, [sp,#-16]! mov fp, sp G_M16463_IG02: - mov w0, w0 - lsl x0, x0, #2 + ubfiz x0, x0, #2, #32 G_M16463_IG03: ldp fp, lr, [sp],#16 ret lr -; Total bytes of code: 24 +; Total bytes of code: 20 ; Method Prog:Test2(System.Int32[],int):int G_M15622_IG01: stp fp, lr, [sp,#-16]! mov fp, sp G_M15622_IG02: ldr w2, [x0,#8] cmp w1, w2 bhs G_M15622_IG04 - mov w1, w1 - lsl x1, x1, #2 + ubfiz x1, x1, #2, #32 add x1, x1, #16 ldr w0, [x0, x1] G_M15622_IG03: ldp fp, lr, [sp],#16 ret lr G_M15622_IG04: bl CORINFO_HELP_RNGCHKFAIL bkpt -; Total bytes of code: 52 +; Total bytes of code: 48Diffs are impressive and gives us a hint we should implement proper "addressing modes" for arm64 asap 🙂
coreclr_tests.pmi.Linux.arm64.checked.mch:
Detail diffs
libraries.crossgen2.Linux.arm64.checked.mch:
Detail diffs
libraries.pmi.Linux.arm64.checked.mch:
Detail diffs
libraries_tests.pmi.Linux.arm64.checked.mch:
Detail diffs