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[PHIElimination] Verify reappropriated COPY is of similar register class, update livevars. (#146337)
Follow up to the second bug that #131837 introduced, described in #131837 (comment).
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3 files changed

+101
-23
lines changed

‎llvm/lib/CodeGen/PHIElimination.cpp‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -584,9 +584,13 @@ void PHIEliminationImpl::LowerPHINode(MachineBasicBlock &MBB,
584584
// Reuse an existing copy in the block if possible.
585585
if (IncomingReg.isVirtual()) {
586586
MachineInstr *DefMI = MRI->getUniqueVRegDef(SrcReg);
587+
const TargetRegisterClass *SrcRC = MRI->getRegClass(SrcReg);
588+
const TargetRegisterClass *IncomingRC = MRI->getRegClass(IncomingReg);
587589
if (DefMI && DefMI->isCopy() && DefMI->getParent() == &opBlock &&
588-
MRI->use_empty(SrcReg)) {
590+
MRI->use_empty(SrcReg) && IncomingRC->hasSuperClassEq(SrcRC)) {
589591
DefMI->getOperand(0).setReg(IncomingReg);
592+
if (LV)
593+
LV->getVarInfo(SrcReg).AliveBlocks.clear();
590594
continue;
591595
}
592596
}

‎llvm/test/CodeGen/AArch64/PHIElimination-reuse-copy.mir‎

Lines changed: 88 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
2-
# RUN: llc -run-pass=phi-node-elimination -mtriple=aarch64-linux-gnu -o - %s | FileCheck %s
2+
# RUN: llc -run-pass=livevars,phi-node-elimination -verify-machineinstrs -mtriple=aarch64-linux-gnu -o - %s | FileCheck %s
33

44
# Verify that the original COPY in bb.1 is reappropriated as the PHI source in bb.2,
55
# instead of creating a new COPY with the same source register.
@@ -13,18 +13,18 @@ body: |
1313
; CHECK-NEXT: successors: %bb.2(0x40000000), %bb.1(0x40000000)
1414
; CHECK-NEXT: liveins: $nzcv, $w0
1515
; CHECK-NEXT: {{ $}}
16-
; CHECK-NEXT: %a:gpr32 = COPY $w0
16+
; CHECK-NEXT: %a:gpr32 = COPY killed $w0
1717
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr32 = IMPLICIT_DEF
18-
; CHECK-NEXT: Bcc 8, %bb.2, implicit $nzcv
18+
; CHECK-NEXT: Bcc 8, %bb.2, implicit killed $nzcv
1919
; CHECK-NEXT: {{ $}}
2020
; CHECK-NEXT: bb.1:
2121
; CHECK-NEXT: successors: %bb.2(0x80000000)
2222
; CHECK-NEXT: {{ $}}
23-
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr32 = COPY %a
23+
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr32 = COPY killed %a
2424
; CHECK-NEXT: {{ $}}
2525
; CHECK-NEXT: bb.2:
26-
; CHECK-NEXT: %c:gpr32 = COPY [[DEF]]
27-
; CHECK-NEXT: %d:gpr32 = COPY %c
26+
; CHECK-NEXT: %c:gpr32 = COPY killed [[DEF]]
27+
; CHECK-NEXT: dead %d:gpr32 = COPY killed %c
2828
bb.0:
2929
liveins: $nzcv, $w0
3030
%a:gpr32 = COPY $w0
@@ -46,16 +46,16 @@ body: |
4646
; CHECK-NEXT: liveins: $nzcv, $w0
4747
; CHECK-NEXT: {{ $}}
4848
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr32 = IMPLICIT_DEF
49-
; CHECK-NEXT: Bcc 8, %bb.2, implicit $nzcv
49+
; CHECK-NEXT: Bcc 8, %bb.2, implicit killed $nzcv
5050
; CHECK-NEXT: {{ $}}
5151
; CHECK-NEXT: bb.1:
5252
; CHECK-NEXT: successors: %bb.2(0x80000000)
5353
; CHECK-NEXT: {{ $}}
54-
; CHECK-NEXT: $x0 = IMPLICIT_DEF
55-
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr32 = COPY $w0
54+
; CHECK-NEXT: dead $x0 = IMPLICIT_DEF implicit-def $w0
55+
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr32 = COPY killed $w0
5656
; CHECK-NEXT: {{ $}}
5757
; CHECK-NEXT: bb.2:
58-
; CHECK-NEXT: %b:gpr32 = COPY [[DEF]]
58+
; CHECK-NEXT: dead %b:gpr32 = COPY killed [[DEF]]
5959
bb.0:
6060
liveins: $nzcv, $w0
6161
Bcc 8, %bb.2, implicit $nzcv
@@ -83,15 +83,15 @@ body: |
8383
; CHECK-NEXT: bb.1:
8484
; CHECK-NEXT: successors: %bb.2(0x80000000)
8585
; CHECK-NEXT: {{ $}}
86-
; CHECK-NEXT: [[DEF:%[0-9]+]]:gpr64 = IMPLICIT_DEF
87-
; CHECK-NEXT: [[DEF1:%[0-9]+]]:gpr64 = IMPLICIT_DEF
86+
; CHECK-NEXT: dead [[DEF:%[0-9]+]]:gpr64 = IMPLICIT_DEF
87+
; CHECK-NEXT: dead [[DEF1:%[0-9]+]]:gpr64 = IMPLICIT_DEF
8888
; CHECK-NEXT: B %bb.2
8989
; CHECK-NEXT: {{ $}}
9090
; CHECK-NEXT: bb.2:
9191
; CHECK-NEXT: successors: %bb.1(0x80000000)
9292
; CHECK-NEXT: {{ $}}
93-
; CHECK-NEXT: [[DEF2:%[0-9]+]]:gpr64 = IMPLICIT_DEF
94-
; CHECK-NEXT: [[DEF3:%[0-9]+]]:gpr64 = IMPLICIT_DEF
93+
; CHECK-NEXT: dead [[DEF2:%[0-9]+]]:gpr64 = IMPLICIT_DEF
94+
; CHECK-NEXT: dead [[DEF3:%[0-9]+]]:gpr64 = IMPLICIT_DEF
9595
; CHECK-NEXT: B %bb.1
9696
bb.0:
9797
liveins: $wzr, $xzr
@@ -117,3 +117,77 @@ body: |
117117
118118
...
119119

120+
---
121+
name: update_livevars
122+
tracksRegLiveness: true
123+
body: |
124+
; CHECK-LABEL: name: update_livevars
125+
; CHECK: bb.0:
126+
; CHECK-NEXT: successors: %bb.1(0x80000000)
127+
; CHECK-NEXT: liveins: $w0, $w1, $nzcv
128+
; CHECK-NEXT: {{ $}}
129+
; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr32 = COPY killed $w0
130+
; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr32 = COPY killed $w1
131+
; CHECK-NEXT: B %bb.1
132+
; CHECK-NEXT: {{ $}}
133+
; CHECK-NEXT: bb.1:
134+
; CHECK-NEXT: successors: %bb.2(0x40000000), %bb.1(0x40000000)
135+
; CHECK-NEXT: liveins: $nzcv
136+
; CHECK-NEXT: {{ $}}
137+
; CHECK-NEXT: dead [[COPY2:%[0-9]+]]:gpr32 = COPY killed [[COPY1]]
138+
; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr32 = COPY [[COPY]]
139+
; CHECK-NEXT: Bcc 1, %bb.1, implicit $nzcv
140+
; CHECK-NEXT: {{ $}}
141+
; CHECK-NEXT: bb.2:
142+
; CHECK-NEXT: successors: %bb.1(0x80000000)
143+
; CHECK-NEXT: liveins: $nzcv
144+
; CHECK-NEXT: {{ $}}
145+
; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr32 = IMPLICIT_DEF
146+
; CHECK-NEXT: B %bb.1
147+
bb.0:
148+
successors: %bb.1
149+
liveins: $w0, $w1, $nzcv
150+
151+
%0:gpr32 = COPY killed $w0
152+
%1:gpr32 = COPY killed $w1
153+
B %bb.1
154+
155+
bb.1:
156+
successors: %bb.2, %bb.1
157+
liveins: $nzcv
158+
159+
%2:gpr32 = PHI %3, %bb.2, %1, %bb.0, %3, %bb.1
160+
%3:gpr32 = COPY %0
161+
Bcc 1, %bb.1, implicit $nzcv
162+
163+
bb.2:
164+
successors: %bb.1
165+
liveins: $nzcv
166+
167+
B %bb.1
168+
...
169+
170+
---
171+
name: copy_subreg
172+
tracksRegLiveness: true
173+
body: |
174+
; CHECK-LABEL: name: copy_subreg
175+
; CHECK: bb.0:
176+
; CHECK-NEXT: successors: %bb.1(0x80000000)
177+
; CHECK-NEXT: liveins: $x0
178+
; CHECK-NEXT: {{ $}}
179+
; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr64 = COPY killed $x0
180+
; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr64 = COPY killed [[COPY]]
181+
; CHECK-NEXT: {{ $}}
182+
; CHECK-NEXT: bb.1:
183+
; CHECK-NEXT: dead [[COPY2:%[0-9]+]]:gpr32 = COPY killed [[COPY1]].sub_32
184+
bb.0:
185+
successors: %bb.1
186+
liveins: $x0
187+
188+
%0:gpr64 = COPY killed $x0
189+
%1:gpr64 = COPY killed %0
190+
191+
bb.1:
192+
%2:gpr32 = PHI %1.sub_32, %bb.0
193+
...

‎llvm/test/CodeGen/AArch64/tbl-loops.ll‎

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -17,18 +17,18 @@ define void @loop1(ptr noalias nocapture noundef writeonly %dst, ptr nocapture n
1717
; CHECK-NEXT: .LBB0_3: // %vector.ph
1818
; CHECK-NEXT: add x11, x8, #1
1919
; CHECK-NEXT: mov w8, #1132396544 // =0x437f0000
20-
; CHECK-NEXT: add x13, x0, #4
20+
; CHECK-NEXT: add x12, x0, #4
2121
; CHECK-NEXT: and x10, x11, #0x1fffffff8
2222
; CHECK-NEXT: dup v0.4s, w8
23-
; CHECK-NEXT: add x14, x1, #16
23+
; CHECK-NEXT: add x13, x1, #16
2424
; CHECK-NEXT: add x8, x1, x10, lsl #2
25-
; CHECK-NEXT: mov x12, x10
2625
; CHECK-NEXT: add x9, x0, x10
26+
; CHECK-NEXT: mov x14, x10
2727
; CHECK-NEXT: .LBB0_4: // %vector.body
2828
; CHECK-NEXT: // =>This Inner Loop Header: Depth=1
29-
; CHECK-NEXT: ldp q1, q2, [x14, #-16]
30-
; CHECK-NEXT: subs x12, x12, #8
31-
; CHECK-NEXT: add x14, x14, #32
29+
; CHECK-NEXT: ldp q1, q2, [x13, #-16]
30+
; CHECK-NEXT: subs x14, x14, #8
31+
; CHECK-NEXT: add x13, x13, #32
3232
; CHECK-NEXT: fcmgt v3.4s, v1.4s, v0.4s
3333
; CHECK-NEXT: fcmgt v4.4s, v2.4s, v0.4s
3434
; CHECK-NEXT: fcmlt v5.4s, v1.4s, #0.0
@@ -44,8 +44,8 @@ define void @loop1(ptr noalias nocapture noundef writeonly %dst, ptr nocapture n
4444
; CHECK-NEXT: uzp1 v1.8b, v1.8b, v0.8b
4545
; CHECK-NEXT: uzp1 v2.8b, v2.8b, v0.8b
4646
; CHECK-NEXT: mov v1.s[1], v2.s[0]
47-
; CHECK-NEXT: stur d1, [x13, #-4]
48-
; CHECK-NEXT: add x13, x13, #8
47+
; CHECK-NEXT: stur d1, [x12, #-4]
48+
; CHECK-NEXT: add x12, x12, #8
4949
; CHECK-NEXT: b.ne .LBB0_4
5050
; CHECK-NEXT: // %bb.5: // %middle.block
5151
; CHECK-NEXT: cmp x11, x10

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