Remove a redundant assertion in MachineBasicBlock.cpp. NFC.

[oota-llvm.git] / lib / Support / StringMap.cpp

diff --git a/lib/Support/StringMap.cpp b/lib/Support/StringMap.cpp
index c2fc261df3a66a3d771b7a8b9588aa9109f5b62f..7be946642d9070987dcd429df8254d769f364325 100644 (file)
--- a/lib/Support/StringMap.cpp
+++ b/lib/Support/StringMap.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Compiler.h"
 #include <cassert>
 using namespace llvm;
 
@@ -26,7 +27,7 @@ StringMapImpl::StringMapImpl(unsigned InitSize, unsigned itemSize) {
   }
   
   // Otherwise, initialize it with zero buckets to avoid the allocation.
-  TheTable = 0;
+  TheTable = nullptr;
   NumBuckets = 0;
   NumItems = 0;
   NumTombstones = 0;
@@ -69,7 +70,7 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) {
   while (1) {
     StringMapEntryBase *BucketItem = TheTable[BucketNo];
     // If we found an empty bucket, this key isn't in the table yet, return it.
-    if (BucketItem == 0) {
+    if (LLVM_LIKELY(!BucketItem)) {
       // If we found a tombstone, we want to reuse the tombstone instead of an
       // empty bucket.  This reduces probing.
       if (FirstTombstone != -1) {
@@ -84,7 +85,7 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) {
     if (BucketItem == getTombstoneVal()) {
       // Skip over tombstones.  However, remember the first one we see.
       if (FirstTombstone == -1) FirstTombstone = BucketNo;
-    } else if (HashTable[BucketNo] == FullHashValue) {
+    } else if (LLVM_LIKELY(HashTable[BucketNo] == FullHashValue)) {
       // If the full hash value matches, check deeply for a match.  The common
       // case here is that we are only looking at the buckets (for item info
       // being non-null and for the full hash value) not at the items.  This
@@ -123,12 +124,12 @@ int StringMapImpl::FindKey(StringRef Key) const {
   while (1) {
     StringMapEntryBase *BucketItem = TheTable[BucketNo];
     // If we found an empty bucket, this key isn't in the table yet, return.
-    if (BucketItem == 0)
+    if (LLVM_LIKELY(!BucketItem))
       return -1;
     
     if (BucketItem == getTombstoneVal()) {
       // Ignore tombstones.
-    } else if (HashTable[BucketNo] == FullHashValue) {
+    } else if (LLVM_LIKELY(HashTable[BucketNo] == FullHashValue)) {
       // If the full hash value matches, check deeply for a match.  The common
       // case here is that we are only looking at the buckets (for item info
       // being non-null and for the full hash value) not at the items.  This
@@ -165,7 +166,7 @@ void StringMapImpl::RemoveKey(StringMapEntryBase *V) {
 /// table, returning it.  If the key is not in the table, this returns null.
 StringMapEntryBase *StringMapImpl::RemoveKey(StringRef Key) {
   int Bucket = FindKey(Key);
-  if (Bucket == -1) return 0;
+  if (Bucket == -1) return nullptr;
   
   StringMapEntryBase *Result = TheTable[Bucket];
   TheTable[Bucket] = getTombstoneVal();
@@ -180,21 +181,23 @@ StringMapEntryBase *StringMapImpl::RemoveKey(StringRef Key) {
 
 /// RehashTable - Grow the table, redistributing values into the buckets with
 /// the appropriate mod-of-hashtable-size.
-void StringMapImpl::RehashTable() {
+unsigned StringMapImpl::RehashTable(unsigned BucketNo) {
   unsigned NewSize;
   unsigned *HashTable = (unsigned *)(TheTable + NumBuckets + 1);
 
   // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
   // the buckets are empty (meaning that many are filled with tombstones),
   // grow/rehash the table.
-  if (NumItems*4 > NumBuckets*3) {
+  if (LLVM_UNLIKELY(NumItems * 4 > NumBuckets * 3)) {
     NewSize = NumBuckets*2;
-  } else if (NumBuckets-(NumItems+NumTombstones) <= NumBuckets/8) {
+  } else if (LLVM_UNLIKELY(NumBuckets - (NumItems + NumTombstones) <=
+                           NumBuckets / 8)) {
     NewSize = NumBuckets;
   } else {
-    return;
+    return BucketNo;
   }
 
+  unsigned NewBucketNo = BucketNo;
   // Allocate one extra bucket which will always be non-empty.  This allows the
   // iterators to stop at end.
   StringMapEntryBase **NewTableArray =
@@ -211,9 +214,11 @@ void StringMapImpl::RehashTable() {
       // Fast case, bucket available.
       unsigned FullHash = HashTable[I];
       unsigned NewBucket = FullHash & (NewSize-1);
-      if (NewTableArray[NewBucket] == 0) {
+      if (!NewTableArray[NewBucket]) {
         NewTableArray[FullHash & (NewSize-1)] = Bucket;
         NewHashArray[FullHash & (NewSize-1)] = FullHash;
+        if (I == BucketNo)
+          NewBucketNo = NewBucket;
         continue;
       }
       
@@ -226,6 +231,8 @@ void StringMapImpl::RehashTable() {
       // Finally found a slot.  Fill it in.
       NewTableArray[NewBucket] = Bucket;
       NewHashArray[NewBucket] = FullHash;
+      if (I == BucketNo)
+        NewBucketNo = NewBucket;
     }
   }
   
@@ -234,4 +241,5 @@ void StringMapImpl::RehashTable() {
   TheTable = NewTableArray;
   NumBuckets = NewSize;
   NumTombstones = 0;
+  return NewBucketNo;
 }