format & handle cases where cache size is 1

Author: DingdWang

llvm/lib/Analysis/MemoryDependenceAnalysis.cpp

@@ -51,7 +51,6 @@
 #include <cassert>
 #include <iterator>
 #include <utility>
-#include <cmath>
 
 using namespace llvm;
 
@@ -84,9 +83,6 @@ static cl::opt<unsigned>
 // Limit on the number of memdep results to process.
 static const unsigned int NumResultsLimit = 100;
 
-// for quickly calculating log
-const float ln2 = 0.69314718f;
-
 /// This is a helper function that removes Val from 'Inst's set in ReverseMap.
 ///
 /// If the set becomes empty, remove Inst's entry.
@@ -995,19 +991,19 @@ MemDepResult MemoryDependenceResults::getNonLocalInfoForBlock(
 static void
 SortNonLocalDepInfoCache(MemoryDependenceResults::NonLocalDepInfo &Cache,
                          unsigned NumSortedEntries) {
-
+  if (Cache.size() == 1)
+    return;
   auto s = Cache.size() - NumSortedEntries;
-  if (s < log2(Cache.size()) * ln2) {
-    while (s>0) {
+  if (s < Log2_32(Cache.size()) * llvm::numbers::ln2) {
+    while (s > 0) {
       NonLocalDepEntry Val = Cache.back();
       Cache.pop_back();
       MemoryDependenceResults::NonLocalDepInfo::iterator Entry =
-        std::upper_bound(Cache.begin(), Cache.end() - 1, Val);
+          llvm::upper_bound(Cache, Val);
       Cache.insert(Entry, Val);
       s--;
     }
-  }
-  else {
+  } else {
     llvm::sort(Cache);
   }
 }