Write /* static */ if as if /* constexpr */

Summary: [Folly] Write `/* static */ if` as `if /* constexpr */`. Once the time comes to jump to C++17, all that remains is to remove the comments.

Reviewed By: aary

Differential Revision: D9627826

fbshipit-source-id: 56078e727a3a4420851f1c441783b80da55a8e6c

folly/ConcurrentSkipList.h

@@ -197,7 +197,7 @@ class ConcurrentSkipList {
   //===================================================================
 
   ~ConcurrentSkipList() {
-    /* static */ if (NodeType::template DestroyIsNoOp<NodeAlloc>::value) {
+    if /* constexpr */ (NodeType::template DestroyIsNoOp<NodeAlloc>::value) {
       // Avoid traversing the list if using arena allocator.
       return;
     }

folly/Conv.h

@@ -1224,14 +1224,14 @@ typename std::enable_if<
         std::is_integral<Tgt>::value,
     Expected<Tgt, ConversionCode>>::type
 convertTo(const Src& value) noexcept {
-  /* static */ if (
+  if /* constexpr */ (
       folly::_t<std::make_unsigned<Tgt>>(std::numeric_limits<Tgt>::max()) <
       folly::_t<std::make_unsigned<Src>>(std::numeric_limits<Src>::max())) {
     if (greater_than<Tgt, std::numeric_limits<Tgt>::max()>(value)) {
       return makeUnexpected(ConversionCode::ARITH_POSITIVE_OVERFLOW);
     }
   }
-  /* static */ if (
+  if /* constexpr */ (
       std::is_signed<Src>::value &&
       (!std::is_signed<Tgt>::value || sizeof(Src) > sizeof(Tgt))) {
     if (less_than<Tgt, std::numeric_limits<Tgt>::min()>(value)) {
@@ -1252,7 +1252,7 @@ typename std::enable_if<
         !std::is_same<Tgt, Src>::value,
     Expected<Tgt, ConversionCode>>::type
 convertTo(const Src& value) noexcept {
-  /* static */ if (
+  if /* constexpr */ (
       std::numeric_limits<Tgt>::max() < std::numeric_limits<Src>::max()) {
     if (value > std::numeric_limits<Tgt>::max()) {
       return makeUnexpected(ConversionCode::ARITH_POSITIVE_OVERFLOW);

folly/FBString.h

@@ -141,7 +141,7 @@ template <class Pod, class T>
 inline void podFill(Pod* b, Pod* e, T c) {
   FBSTRING_ASSERT(b && e && b <= e);
   constexpr auto kUseMemset = sizeof(T) == 1;
-  /* static */ if (kUseMemset) {
+  if /* constexpr */ (kUseMemset) {
     memset(b, c, size_t(e - b));
   } else {
     auto const ee = b + ((e - b) & ~7u);
@@ -477,7 +477,7 @@ template <class Char> class fbstring_core {
 
   size_t size() const {
     size_t ret = ml_.size_;
-    /* static */ if (kIsLittleEndian) {
+    if /* constexpr */ (kIsLittleEndian) {
       // We can save a couple instructions, because the category is
       // small iff the last char, as unsigned, is <= maxSmallSize.
       typedef typename std::make_unsigned<Char>::type UChar;

folly/experimental/EliasFanoCoding.h

@@ -171,14 +171,14 @@ struct EliasFanoEncoderV2 {
       writeBits56(lower_, size_ * numLowerBits, numLowerBits, lowerBits);
     }
 
-    /* static */ if (skipQuantum != 0) {
+    if /* constexpr */ (skipQuantum != 0) {
       while ((skipPointersSize_ + 1) * skipQuantum <= upperBits) {
         // Store the number of preceding 1-bits.
         skipPointers_[skipPointersSize_++] = SkipValue(size_);
       }
     }
 
-    /* static */ if (forwardQuantum != 0) {
+    if /* constexpr */ (forwardQuantum != 0) {
       if ((size_ + 1) % forwardQuantum == 0) {
         const auto k = size_ / forwardQuantum;
         // Store the number of preceding 0-bits.
@@ -264,7 +264,7 @@ struct EliasFanoEncoderV2<Value,
     // *** Skip pointers.
     // Store (1-indexed) position of every skipQuantum-th
     // 0-bit in upper bits sequence.
-    /* static */ if (skipQuantum != 0) {
+    if /* constexpr */ (skipQuantum != 0) {
       // 8 * upper is used here instead of upperSizeBits, as that is
       // more serialization-friendly way (upperSizeBits doesn't need
       // to be known by this function, unlike upper).
@@ -276,7 +276,7 @@ struct EliasFanoEncoderV2<Value,
     // *** Forward pointers.
     // Store (1-indexed) position of every forwardQuantum-th
     // 1-bit in upper bits sequence.
-    /* static */ if (forwardQuantum != 0) {
+    if /* constexpr */ (forwardQuantum != 0) {
       size_t numForwardPointers = size / forwardQuantum;
       layout.forwardPointers = numForwardPointers * sizeof(SkipValueType);
     }

folly/hash/Hash.h

@@ -94,7 +94,7 @@ size_t hash_combine_generic(
     return seed;
   }
   size_t remainder = hash_combine_generic(h, ts...);
-  /* static */ if (sizeof(size_t) == sizeof(uint32_t)) {
+  if /* constexpr */ (sizeof(size_t) == sizeof(uint32_t)) {
     return twang_32from64((uint64_t(seed) << 32) | remainder);
   } else {
     return static_cast<size_t>(hash_128_to_64(seed, remainder));

folly/test/ProducerConsumerQueueTest.cpp

@@ -73,7 +73,7 @@ struct PerfTest {
   }
 
   void consumer() {
-    /*static*/ if (Pop) {
+    if /* constexpr */ (Pop) {
       while (!done_) {
         if (queue_.frontPtr()) {
           queue_.popFront();