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[RISCV][VLOPT] Set CommonVL as the largest of the users #120349

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Merged
merged 1 commit into from
Dec 19, 2024
Merged

[RISCV][VLOPT] Set CommonVL as the largest of the users #120349

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10 changes: 5 additions & 5 deletions llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -936,13 +936,13 @@ bool RISCVVLOptimizer::checkUsers(const MachineOperand *&CommonVL,
assert((!VLOp.isReg() || VLOp.getReg() != RISCV::X0) &&
"Did not expect X0 VL");

if (!CommonVL) {
// Use the largest VL among all the users. If we cannot determine this
// statically, then we cannot optimize the VL.
if (!CommonVL || RISCV::isVLKnownLE(*CommonVL, VLOp)) {
CommonVL = &VLOp;
LLVM_DEBUG(dbgs() << " User VL is: " << VLOp << "\n");
} else if (!CommonVL->isIdenticalTo(VLOp)) {
// FIXME: This check requires all users to have the same VL. We can relax
// this and get the largest VL amongst all users.
LLVM_DEBUG(dbgs() << " Abort because users have different VL\n");
} else if (!RISCV::isVLKnownLE(VLOp, *CommonVL)) {
LLVM_DEBUG(dbgs() << " Abort because cannot determine a common VL\n");
CanReduceVL = false;
break;
}
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78 changes: 78 additions & 0 deletions llvm/test/CodeGen/RISCV/rvv/vl-opt.mir
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Expand Up @@ -33,3 +33,81 @@ body: |
%y:vr = PseudoVREDSUM_VS_M1_E64 $noreg, %x, $noreg, -1, 6 /* e64 */, 0 /* tu, mu */
%z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 5 /* e32 */, 0 /* tu, mu */
...
---
name: use_largest_common_vl_imm_imm
body: |
bb.0:
; CHECK-LABEL: name: use_largest_common_vl_imm_imm
; CHECK: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 2, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 2, 3 /* e8 */, 0 /* tu, mu */
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
%y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0
%z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 2, 3 /* e8 */, 0
...
---
name: use_largest_common_vl_same_reg
body: |
bb.0:
liveins: $x1
; CHECK-LABEL: name: use_largest_common_vl_same_reg
; CHECK: liveins: $x1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %vl:gprnox0 = COPY $x1
; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, %vl, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0 /* tu, mu */
%vl:gprnox0 = COPY $x1
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
%y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0
%z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0
...
---
name: use_largest_common_vl_diff_regs
body: |
bb.0:
liveins: $x1, $x2
; CHECK-LABEL: name: use_largest_common_vl_diff_regs
; CHECK: liveins: $x1, $x2
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %vl0:gprnox0 = COPY $x1
; CHECK-NEXT: %vl1:gprnox0 = COPY $x2
; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl0, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl1, 3 /* e8 */, 0 /* tu, mu */
%vl0:gprnox0 = COPY $x1
%vl1:gprnox0 = COPY $x2
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
%y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl0, 3 /* e8 */, 0
%z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl1, 3 /* e8 */, 0
...
---
name: use_largest_common_vl_imm_reg
body: |
bb.0:
liveins: $x1
; CHECK-LABEL: name: use_largest_common_vl_imm_reg
; CHECK: liveins: $x1
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %vl:gprnox0 = COPY $x1
; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
%vl:gprnox0 = COPY $x1
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
%y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0
%z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0
...
---
name: use_largest_common_vl_imm_vlmax
body: |
bb.0:
; CHECK-LABEL: name: use_largest_common_vl_imm_vlmax
; CHECK: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
%x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
%y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0
%z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, -1, 3 /* e8 */, 0
...

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