[RISCV] Move comments before 'if' instead of after. NFC

[craig.topper]

Summary

This allows us to remove some curly braces around the if body.
The code wasn't consistent about it anyway. Comments before is
used in other places in this file already.

[wangpc]

LGTM

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

 //===-- RISCVISelLowering.cpp - RISC-V DAG Lowering Implementation  -------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
SDValue RISCVTargetLowering::lowerSELECT(SDValue Op, SelectionDAG &DAG) const {
 
   // When Zicond is present, emit CZERO_EQZ and CZERO_NEZ nodes to implement
   // the SELECT. Performing the lowering here allows for greater control over
   // when CZERO_{EQZ/NEZ} are used vs another branchless sequence or
   // RISCVISD::SELECT_CC node (branch-based select).
   if (Subtarget.hasStdExtZicond() && VT.isInteger()) {
     SDValue NewCondV;
     if (selectSETCC(CondV, ISD::SETNE, NewCondV, DAG)) {
-      if (isNullConstant(FalseV))
-        // (select (riscv_setne c), t, 0) -> (czero_eqz t, c)
+      if (isNullConstant(FalseV))
         return DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, TrueV, NewCondV);
-      if (isNullConstant(TrueV))
-        // (select (riscv_setne c), 0, f) -> (czero_nez f, c)
+      if (isNullConstant(TrueV))
         return DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, FalseV, NewCondV);
       // (select (riscv_setne c), t, f) -> (or (czero_eqz t, c), (czero_nez f,
       // c)
       return DAG.getNode(
           ISD::OR, DL, VT,
           DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, TrueV, NewCondV),
           DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, FalseV, NewCondV));
     }
     if (selectSETCC(CondV, ISD::SETEQ, NewCondV, DAG)) {
-      if (isNullConstant(FalseV))
-        // (select (riscv_seteq c), t, 0) -> (czero_nez t, c)
+      if (isNullConstant(FalseV))
         return DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, TrueV, NewCondV);
-      if (isNullConstant(TrueV))
-        // (select (riscv_seteq c), 0, f) -> (czero_eqz f, c)
+      if (isNullConstant(TrueV))
         return DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, FalseV, NewCondV);
       // (select (riscv_seteq c), t, f) -> (or (czero_eqz f, c), (czero_nez t,
       // c)
       return DAG.getNode(
           ISD::OR, DL, VT,
           DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, FalseV, NewCondV),
           DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, TrueV, NewCondV));
     }
-    if (isNullConstant(FalseV)) {
-      // (select c, t, 0) -> (czero_eqz t, c)
+
+    if (isNullConstant(FalseV))
       return DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, TrueV, CondV);
-    }
-    if (isNullConstant(TrueV)) {
-      // (select c, 0, f) -> (czero_nez f, c)
+    if (isNullConstant(TrueV))
       return DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, FalseV, CondV);
-    }
-    if (TrueV.getOpcode() == ISD::AND &&
-        (TrueV.getOperand(0) == FalseV || TrueV.getOperand(1) == FalseV)) {
-      // (select c, (and f, x), f) -> (or (and f, x), (czero_nez f, c))
+
+    if (TrueV.getOpcode() == ISD::AND &&
+        (TrueV.getOperand(0) == FalseV || TrueV.getOperand(1) == FalseV))
       return DAG.getNode(
           ISD::OR, DL, VT, TrueV,
           DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, FalseV, CondV));
-    }
-    if (FalseV.getOpcode() == ISD::AND &&
-        (FalseV.getOperand(0) == TrueV || FalseV.getOperand(1) == TrueV)) {
-      // (select c, t, (and t, x)) -> (or (czero_eqz t, c), (and t, x))
+    if (FalseV.getOpcode() == ISD::AND &&
+        (FalseV.getOperand(0) == TrueV || FalseV.getOperand(1) == TrueV))
       return DAG.getNode(
           ISD::OR, DL, VT, FalseV,
           DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, TrueV, CondV));
-    }
+
     // (select c, t, f) -> (or (czero_eqz t, c), (czero_nez f, c))
     return DAG.getNode(ISD::OR, DL, VT,
                        DAG.getNode(RISCVISD::CZERO_EQZ, DL, VT, TrueV, CondV),
                        DAG.getNode(RISCVISD::CZERO_NEZ, DL, VT, FalseV, CondV));
   }
 
   if (SDValue V = combineSelectToBinOp(Op.getNode(), DAG, Subtarget))
     return V;