[llvm] r276278 - [DemandedBits] Reduce number of duplicated DenseMap lookups.

[Benjamin Kramer via llvm-commits]

Author: d0k
Date: Thu Jul 21 08:37:55 2016
New Revision: 276278

URL: http://llvm.org/viewvc/llvm-project?rev=276278&view=rev
Log:
[DemandedBits] Reduce number of duplicated DenseMap lookups.

No functionality change intended.

Modified:
    llvm/trunk/lib/Analysis/DemandedBits.cpp

Modified: llvm/trunk/lib/Analysis/DemandedBits.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/DemandedBits.cpp?rev=276278&r1=276277&r2=276278&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/DemandedBits.cpp (original)
+++ llvm/trunk/lib/Analysis/DemandedBits.cpp Thu Jul 21 08:37:55 2016
@@ -280,10 +280,8 @@ void DemandedBits::performAnalysis() {
     // add their operands to the work list (for integer values operands, mark
     // all bits as live).
     if (IntegerType *IT = dyn_cast<IntegerType>(I.getType())) {
-      if (!AliveBits.count(&I)) {
-        AliveBits[&I] = APInt(IT->getBitWidth(), 0);
+      if (AliveBits.try_emplace(&I, IT->getBitWidth(), 0).second)
         Worklist.push_back(&I);
-      }
 
       continue;
     }
@@ -363,8 +361,9 @@ APInt DemandedBits::getDemandedBits(Inst
   performAnalysis();
   
   const DataLayout &DL = I->getParent()->getModule()->getDataLayout();
-  if (AliveBits.count(I))
-    return AliveBits[I];
+  auto Found = AliveBits.find(I);
+  if (Found != AliveBits.end())
+    return Found->second;
   return APInt::getAllOnesValue(DL.getTypeSizeInBits(I->getType()));
 }