[llvm][ADT]Remove duplicate code in llvm::StringMapImpl::RehashTable

[yihanaa]

Summary

remove duplicate code in llvm::StringMapImpl::RehashTable, near StringMap.cpp:229

if (!NewTableArray[NewBucket]) {
        NewTableArray[FullHash & (NewSize - 1)] = Bucket;
        NewHashArray[FullHash & (NewSize - 1)] = FullHash;
        if (I == BucketNo)
          NewBucketNo = NewBucket;
        continue;
}

[MaskRay]

Looks great!

[dexonsmith]

LGTM too, assuming you fix the comment, which I think is now backwards (doesn't have to be the wording I suggested inline).

llvm/lib/Support/StringMap.cpp

229–236

I think the comment is backwards now!

I suggest:

// If the bucket is not available, probe for a spot.

238–239

Note that clang-format wants you to do something here.

[yihanaa]

i quite agree with @dexonsmith , and reformatted the code with clang-format

[yihanaa]

In D121726#3383479, @MaskRay wrote:

Looks great!

Thanks @MaskRay . I don’t have commit access, can you land this patch for me? Please use “wangyihan [e-mail]” to commit the change.

llvm/lib/Support/StringMap.cpp

unsigned StringMapImpl::RehashTable(unsigned BucketNo) {
   unsigned *NewHashArray = (unsigned *)(NewTableArray + NewSize + 1);
   NewTableArray[NewSize] = (StringMapEntryBase *)2;
 
   // Rehash all the items into their new buckets.  Luckily :) we already have
   // the hash values available, so we don't have to rehash any strings.
   for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
     StringMapEntryBase *Bucket = TheTable[I];
     if (Bucket && Bucket != getTombstoneVal()) {
-      // Fast case, bucket available.
+      // If the bucket is not available, probe for a spot.
       unsigned FullHash = HashTable[I];
       unsigned NewBucket = FullHash & (NewSize - 1);
-      if (!NewTableArray[NewBucket]) {
-        NewTableArray[FullHash & (NewSize - 1)] = Bucket;
-        NewHashArray[FullHash & (NewSize - 1)] = FullHash;
-        if (I == BucketNo)
-          NewBucketNo = NewBucket;
-        continue;
-      }
-
-      // Otherwise probe for a spot.
+      if (NewTableArray[NewBucket]) {
         unsigned ProbeSize = 1;
         do {
           NewBucket = (NewBucket + ProbeSize++) & (NewSize - 1);
         } while (NewTableArray[NewBucket]);
+      }
 
       // Finally found a slot.  Fill it in.
       NewTableArray[NewBucket] = Bucket;
       NewHashArray[NewBucket] = FullHash;
       if (I == BucketNo)
         NewBucketNo = NewBucket;
     }
   }
 
   free(TheTable);
 
   TheTable = NewTableArray;
   NumBuckets = NewSize;
   NumTombstones = 0;
   return NewBucketNo;
 }