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mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-22 02:33:06 +01:00

[AArch64][GlobalISel] Add identity combines to post-legal combiner.

We see some shifts of zero emitted during legalization.

Differential Revision: https://reviews.llvm.org/D106816
This commit is contained in:
Amara Emerson 2021-07-26 11:46:24 -07:00
parent 3698f6f3f3
commit 6634a71bd1
5 changed files with 30 additions and 13 deletions

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@ -212,6 +212,6 @@ def AArch64PostLegalizerCombinerHelper
form_bitfield_extract, rotate_out_of_range,
icmp_to_true_false_known_bits, merge_unmerge,
select_combines, fold_merge_to_zext,
constant_fold]> {
constant_fold, identity_combines]> {
let DisableRuleOption = "aarch64postlegalizercombiner-disable-rule";
}

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@ -350,10 +350,8 @@ define void @atomic_load_relaxed(i64, i64, i128* %p, i128* %p2) {
; CHECK-LLSC-O1-NEXT: .LBB4_1: // %atomicrmw.start
; CHECK-LLSC-O1-NEXT: // =>This Inner Loop Header: Depth=1
; CHECK-LLSC-O1-NEXT: ldxp x9, x8, [x2]
; CHECK-LLSC-O1-NEXT: lsr x8, x8, #0
; CHECK-LLSC-O1-NEXT: lsr x10, x8, #0
; CHECK-LLSC-O1-NEXT: stxp w11, x9, x10, [x2]
; CHECK-LLSC-O1-NEXT: cbnz w11, .LBB4_1
; CHECK-LLSC-O1-NEXT: stxp w10, x9, x8, [x2]
; CHECK-LLSC-O1-NEXT: cbnz w10, .LBB4_1
; CHECK-LLSC-O1-NEXT: // %bb.2: // %atomicrmw.end
; CHECK-LLSC-O1-NEXT: mov v0.d[0], x9
; CHECK-LLSC-O1-NEXT: mov v0.d[1], x8
@ -365,10 +363,8 @@ define void @atomic_load_relaxed(i64, i64, i128* %p, i128* %p2) {
; CHECK-CAS-O1-NEXT: .LBB4_1: // %atomicrmw.start
; CHECK-CAS-O1-NEXT: // =>This Inner Loop Header: Depth=1
; CHECK-CAS-O1-NEXT: ldxp x9, x8, [x2]
; CHECK-CAS-O1-NEXT: lsr x8, x8, #0
; CHECK-CAS-O1-NEXT: lsr x10, x8, #0
; CHECK-CAS-O1-NEXT: stxp w11, x9, x10, [x2]
; CHECK-CAS-O1-NEXT: cbnz w11, .LBB4_1
; CHECK-CAS-O1-NEXT: stxp w10, x9, x8, [x2]
; CHECK-CAS-O1-NEXT: cbnz w10, .LBB4_1
; CHECK-CAS-O1-NEXT: // %bb.2: // %atomicrmw.end
; CHECK-CAS-O1-NEXT: mov v0.d[0], x9
; CHECK-CAS-O1-NEXT: mov v0.d[1], x8

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@ -0,0 +1,24 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple aarch64 -run-pass=aarch64-postlegalizer-combiner -verify-machineinstrs %s -o - | FileCheck %s
---
name: shift_of_zero
alignment: 4
legalized: true
liveins:
- { reg: '$w0' }
body: |
bb.1.entry:
liveins: $x0
; CHECK-LABEL: name: shift_of_zero
; CHECK: %a:_(s64) = COPY $x0
; CHECK: $x0 = COPY %a(s64)
; CHECK: RET_ReallyLR implicit $x0
%a:_(s64) = COPY $x0
%b:_(s64) = G_CONSTANT i64 0
%res:_(s64) = G_LSHR %a, %b
$x0 = COPY %res(s64)
RET_ReallyLR implicit $x0
...

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@ -9,9 +9,7 @@ body: |
liveins: $x0, $x1
; CHECK-LABEL: name: test_combine_select_same_res
; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[COPY]](s64)
; CHECK: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[TRUNC]](s1), [[COPY]], [[COPY]]
; CHECK: $x0 = COPY [[SELECT]](s64)
; CHECK: $x0 = COPY [[COPY]](s64)
%0:_(s64) = COPY $x0
%1:_(s1) = G_TRUNC %0
%2:_(s64) = G_SELECT %1, %0, %0

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@ -133,7 +133,6 @@ define i32 @f7() {
; GISEL-NEXT: mov v0.d[1], x8
; GISEL-NEXT: mov d0, v0.d[1]
; GISEL-NEXT: fmov x8, d0
; GISEL-NEXT: lsr x8, x8, #0
; GISEL-NEXT: ldr w0, [x8, #20]
; GISEL-NEXT: ret