[llvm] Use std::tie to implement operator< (NFC) (#139391)

Author: kazutakahirata

llvm/include/llvm/Support/InstructionCost.h

@@ -20,6 +20,7 @@
 
 #include "llvm/Support/MathExtras.h"
 #include <limits>
+#include <tuple>
 
 namespace llvm {
 
@@ -191,9 +192,7 @@ class InstructionCost {
   /// the states are valid and users can test for validity of the cost
   /// explicitly.
   bool operator<(const InstructionCost &RHS) const {
-    if (State != RHS.State)
-      return State < RHS.State;
-    return Value < RHS.Value;
+    return std::tie(State, Value) < std::tie(RHS.State, RHS.Value);
   }
 
   bool operator==(const InstructionCost &RHS) const {

llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp

@@ -107,11 +107,7 @@ namespace {
       return !operator==(R);
     }
     bool operator<(const OffsetRange &R) const {
-      if (Min != R.Min)
-        return Min < R.Min;
-      if (Max != R.Max)
-        return Max < R.Max;
-      return Align < R.Align;
+      return std::tie(Min, Max, Align) < std::tie(R.Min, R.Max, R.Align);
     }
     static OffsetRange zero() { return {0, 0, 1}; }
   };