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[RISCV][VLOPT] Look through PHI instructions #132236

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Merged
michaelmaitland merged 7 commits into from
Mar 24, 2025
Merged

[RISCV][VLOPT] Look through PHI instructions #132236

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2513c59
[RISCV][VLOPT] Look through PHI instructions
michaelmaitland Mar 20, 2025
d6462da
fixup! clang-format
michaelmaitland Mar 20, 2025
25edefa
fixup! handle phi loop
michaelmaitland Mar 20, 2025
b1345f6
fixup! improve phi cycle logic
michaelmaitland Mar 20, 2025
b392433
fixup! add another test
michaelmaitland Mar 20, 2025
a268fed
fixup! remove accidental file
michaelmaitland Mar 20, 2025
c37a482
fixup! fix phi cycle logic
michaelmaitland Mar 24, 2025
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7 changes: 7 additions & 0 deletions llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1340,6 +1340,13 @@ RISCVVLOptimizer::checkUsers(const MachineInstr &MI) const {
continue;
}

if (UserMI.isPHI()) {
LLVM_DEBUG(dbgs() << " Peeking through uses of PHI\n");
for (auto &PhiUse : MRI->use_operands(UserMI.getOperand(0).getReg()))
Worklist.insert(&PhiUse);
continue;
}

auto VLOp = getMinimumVLForUser(UserOp);
if (!VLOp)
return std::nullopt;
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84 changes: 84 additions & 0 deletions llvm/test/CodeGen/RISCV/rvv/vl-opt.mir
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Expand Up @@ -368,3 +368,87 @@ body: |
%y:vr = COPY %x
%z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 4 /* e16 */, 0 /* tu, mu */
...
---
name: phi
tracksRegLiveness: true
body: |
; CHECK-LABEL: name: phi
; CHECK: bb.0:
; CHECK-NEXT: successors: %bb.2(0x40000000), %bb.1(0x40000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %w:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: BNE $noreg, $noreg, %bb.2
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
; CHECK-NEXT: successors: %bb.2(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.2:
; CHECK-NEXT: %y:vr = PHI %w, %bb.0, %x, %bb.1
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
bb.0:
%w:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
BNE $noreg, $noreg, %bb.2
bb.1:
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
bb.2:
%y:vr = PHI %w, %bb.0, %x, %bb.1
%z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
...
---
name: phi_user_invalid_sew
tracksRegLiveness: true
body: |
; CHECK-LABEL: name: phi_user_invalid_sew
; CHECK: bb.0:
; CHECK-NEXT: successors: %bb.2(0x40000000), %bb.1(0x40000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %w:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: BNE $noreg, $noreg, %bb.2
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
; CHECK-NEXT: successors: %bb.2(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.2:
; CHECK-NEXT: %y:vr = PHI %w, %bb.0, %x, %bb.1
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 4 /* e16 */, 0 /* tu, mu */
bb.0:
%w:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
BNE $noreg, $noreg, %bb.2
bb.1:
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
bb.2:
%y:vr = PHI %w, %bb.0, %x, %bb.1
%z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 4 /* e16 */, 0 /* tu, mu */
...
---
name: phi_different_incoming_sew
tracksRegLiveness: true
body: |
; CHECK-LABEL: name: phi_different_incoming_sew
; CHECK: bb.0:
; CHECK-NEXT: successors: %bb.2(0x40000000), %bb.1(0x40000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %w:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: BNE $noreg, $noreg, %bb.2
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
; CHECK-NEXT: successors: %bb.2(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 4 /* e16 */, 0 /* tu, mu */
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.2:
; CHECK-NEXT: %y:vr = PHI %w, %bb.0, %x, %bb.1
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
bb.0:
%w:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
BNE $noreg, $noreg, %bb.2
bb.1:
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 4 /* e16 */, 0 /* tu, mu */
bb.2:
%y:vr = PHI %w, %bb.0, %x, %bb.1
%z:vr = PseudoVADD_VV_M1 $noreg, %y, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
...
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