diff --git a/bolt/lib/Core/BinaryBasicBlock.cpp b/bolt/lib/Core/BinaryBasicBlock.cpp
--- a/bolt/lib/Core/BinaryBasicBlock.cpp
+++ b/bolt/lib/Core/BinaryBasicBlock.cpp
@@ -328,6 +328,7 @@
     }
   }
   assert(Erased && "Pred is not a predecessor of this block!");
+  (void)Erased;
 }
 
 void BinaryBasicBlock::removeDuplicateConditionalSuccessor(MCInst *CondBranch) {
diff --git a/bolt/lib/Core/BinaryContext.cpp b/bolt/lib/Core/BinaryContext.cpp
--- a/bolt/lib/Core/BinaryContext.cpp
+++ b/bolt/lib/Core/BinaryContext.cpp
@@ -809,6 +809,7 @@
     break;
   }
   assert(Found && "Label not found");
+  (void)Found;
   MCSymbol *NewLabel = Ctx->createNamedTempSymbol("duplicatedJT");
   JumpTable *NewJT =
       new JumpTable(*NewLabel, JT->getAddress(), JT->EntrySize, JT->Type,
@@ -1172,6 +1173,7 @@
     }
   }
   assert(Valid);
+  (void)Valid;
   generateSymbolHashes();
 }
 
diff --git a/bolt/lib/Rewrite/RewriteInstance.cpp b/bolt/lib/Rewrite/RewriteInstance.cpp
--- a/bolt/lib/Rewrite/RewriteInstance.cpp
+++ b/bolt/lib/Rewrite/RewriteInstance.cpp
@@ -4048,6 +4048,7 @@
 
       if (BSec->getAllocAddress()) {
         assert(!DataWritten && "Writing section twice.");
+        (void)DataWritten;
         SectionData = BSec->getOutputData();
 
         LLVM_DEBUG(dbgs() << "BOLT-DEBUG: " << (Size ? "appending" : "writing")