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[RISCV] Fix coalesced vsetvli's AVL LiveInterval not always being shrunk #98286

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Merged
merged 3 commits into from
Jul 12, 2024
Merged

[RISCV] Fix coalesced vsetvli's AVL LiveInterval not always being shrunk #98286

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bd01c59
[RISCV] Shrink uses of coalesced vsetvlis
lukel97 Jul 10, 2024
3d7ed5f
Store the old register instead of iterating through uses after MI is …
lukel97 Jul 10, 2024
42ae746
Remove redundant shrink
lukel97 Jul 11, 2024
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4 changes: 4 additions & 0 deletions llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1727,6 +1727,10 @@ void RISCVInsertVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) const {
if (LIS)
LIS->RemoveMachineInstrFromMaps(*MI);
MI->eraseFromParent();
if (LIS)
for (MachineOperand &MO : MI->uses())
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@preames preames Jul 10, 2024

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Calling MI->uses() after MI->eraseFromParent() is definitely unsafe.

if (MO.isReg() && MO.getReg().isVirtual())
LIS->shrinkToUses(&LIS->getInterval(MO.getReg()));
}
}

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26 changes: 26 additions & 0 deletions llvm/test/CodeGen/RISCV/rvv/vsetvli-insert.mir
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Expand Up @@ -92,6 +92,10 @@
ret void
}

define void @coalesce_shrink_removed_vsetvlis_uses() {
ret void
}

declare <vscale x 1 x i64> @llvm.riscv.vadd.nxv1i64.nxv1i64.i64(<vscale x 1 x i64>, <vscale x 1 x i64>, <vscale x 1 x i64>, i64) #1

declare <vscale x 1 x i64> @llvm.riscv.vle.nxv1i64.i64(<vscale x 1 x i64>, ptr nocapture, i64) #4
Expand Down Expand Up @@ -576,3 +580,25 @@ body: |
$v0 = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 3, 6, 0
PseudoRET
...
---
name: coalesce_shrink_removed_vsetvlis_uses
tracksRegLiveness: true
body: |
bb.0:
liveins: $x10, $v8
; CHECK-LABEL: name: coalesce_shrink_removed_vsetvlis_uses
; CHECK: liveins: $x10, $v8
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %avl1:gprnox0 = ADDI $x0, 1
; CHECK-NEXT: %avl2:gprnox0 = ADDI $x0, 2
; CHECK-NEXT: dead $x0 = PseudoVSETVLI %avl2, 209 /* e32, m2, ta, ma */, implicit-def $vl, implicit-def $vtype
; CHECK-NEXT: %x:gpr = COPY $x10
; CHECK-NEXT: renamable $v8 = PseudoVMV_S_X undef renamable $v8, %x, 1, 5 /* e32 */, implicit $vl, implicit $vtype
; CHECK-NEXT: PseudoRET implicit $v8
%avl1:gprnox0 = ADDI $x0, 1
dead $x0 = PseudoVSETVLI %avl1:gprnox0, 209, implicit-def dead $vl, implicit-def dead $vtype
%avl2:gprnox0 = ADDI $x0, 2
dead $x0 = PseudoVSETVLI %avl2:gprnox0, 209, implicit-def dead $vl, implicit-def dead $vtype
%x:gpr = COPY $x10
renamable $v8 = PseudoVMV_S_X undef renamable $v8, killed renamable %x, 1, 5
PseudoRET implicit $v8