fixup! respond to review

Author: michaelmaitland

llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp

@@ -50,7 +50,7 @@ class RISCVVLOptimizer : public MachineFunctionPass {
   StringRef getPassName() const override { return PASS_NAME; }
 
 private:
-  std::optional<MachineOperand> getVLForUser(MachineOperand &UserOp);
+  std::optional<MachineOperand> getMinimumVLForUser(MachineOperand &UserOp);
   /// Returns the largest common VL MachineOperand that may be used to optimize
   /// MI. Returns std::nullopt if it failed to find a suitable VL.
   std::optional<MachineOperand> checkUsers(MachineInstr &MI);
@@ -1056,7 +1056,7 @@ bool RISCVVLOptimizer::isCandidate(const MachineInstr &MI) const {
 }
 
 std::optional<MachineOperand>
-RISCVVLOptimizer::getVLForUser(MachineOperand &UserOp) {
+RISCVVLOptimizer::getMinimumVLForUser(MachineOperand &UserOp) {
   const MachineInstr &UserMI = *UserOp.getParent();
   const MCInstrDesc &Desc = UserMI.getDesc();
 
@@ -1081,12 +1081,9 @@ RISCVVLOptimizer::getVLForUser(MachineOperand &UserOp) {
 
     unsigned VLOpNum = RISCVII::getVLOpNum(Desc);
     const MachineOperand &VLOp = UserMI.getOperand(VLOpNum);
-    if (VLOp.isReg() || (VLOp.isImm() && VLOp.getImm() != 0))
-      return MachineOperand::CreateImm(1);
-    LLVM_DEBUG(dbgs() << "    Abort because could not determine VL of vector "
-                         "operand used as scalar operand\n");
-
-    return std::nullopt;
+    return VLOp.isReg() || (VLOp.isImm() && VLOp.getImm() != 0)
+               ? MachineOperand::CreateImm(1)
+               : VLOp;
   }
 
   unsigned VLOpNum = RISCVII::getVLOpNum(Desc);
@@ -1117,7 +1114,7 @@ std::optional<MachineOperand> RISCVVLOptimizer::checkUsers(MachineInstr &MI) {
       return std::nullopt;
     }
 
-    auto VLOp = getVLForUser(UserOp);
+    auto VLOp = getMinimumVLForUser(UserOp);
     if (!VLOp)
       return std::nullopt;
 

llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir

@@ -1160,14 +1160,42 @@ name: vred_both_vl0
 body: |
   bb.0:
     ; CHECK-LABEL: name: vred_both_vl0
-    ; CHECK: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
+    ; CHECK: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 0, 3 /* e8 */, 0 /* tu, mu */
     ; CHECK-NEXT: %y:vr = PseudoVREDSUM_VS_M1_E8 $noreg, $noreg, %x, 0, 3 /* e8 */, 0 /* tu, mu */
     ; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 0, 3 /* e8 */, 0 /* tu, mu */
     %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
     %y:vr = PseudoVREDSUM_VS_M1_E8 $noreg, $noreg, %x, 0, 3 /* e8 */, 0
     %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 0, 3 /* e8 */, 0
 ...
 ---
+name: vred_vl0_and_vlreg
+body: |
+  bb.0:
+    ; CHECK-LABEL: name: vred_vl0_and_vlreg
+    ; CHECK: %vl:gprnox0 = COPY $x1
+    ; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
+    ; CHECK-NEXT: %y:vr = PseudoVREDSUM_VS_M1_E8 $noreg, $noreg, %x, %vl, 3 /* e8 */, 0 /* tu, mu */
+    ; CHECK-NEXT: %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 0, 3 /* e8 */, 0 /* tu, mu */
+    %vl:gprnox0 = COPY $x1
+    %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0
+    %y:vr = PseudoVREDSUM_VS_M1_E8 $noreg, $noreg, %x, %vl, 3 /* e8 */, 0
+    %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 0, 3 /* e8 */, 0
+...
+---
+name: vred_vlreg_and_vl0
+body: |
+  bb.0:
+    ; CHECK-LABEL: name: vred_vlreg_and_vl0
+    ; CHECK: %vl:gprnox0 = COPY $x1
+    ; CHECK-NEXT: %x:vr = PseudoVADD_VV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
+    ; CHECK-NEXT: %y:vr = PseudoVREDSUM_VS_M1_E8 $noreg, $noreg, %x, 0, 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 = PseudoVREDSUM_VS_M1_E8 $noreg, $noreg, %x, 0, 3 /* e8 */, 0
+    %z:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, %vl, 3 /* e8 */, 0
+...
+---
 name: vred_other_user_is_vl2
 body: |
   bb.0: