diff --git a/include/llvm/Bytecode/WriteBytecodePass.h b/include/llvm/Bytecode/WriteBytecodePass.h
index c4e2c5d5d5c..b0155e4ddf6 100644
--- a/include/llvm/Bytecode/WriteBytecodePass.h
+++ b/include/llvm/Bytecode/WriteBytecodePass.h
@@ -27,8 +27,8 @@ class WriteBytecodePass : public ModulePass {
   bool CompressFile;
 public:
   WriteBytecodePass()
-    : Out(&cout), DeleteStream(false), CompressFile(true) {}
-  WriteBytecodePass(OStream *o, bool DS = false, bool CF = true)
+    : Out(&cout), DeleteStream(false), CompressFile(false) {}
+  WriteBytecodePass(OStream *o, bool DS = false, bool CF = false)
     : Out(o), DeleteStream(DS), CompressFile(CF) {}
 
   inline ~WriteBytecodePass() {
diff --git a/include/llvm/Bytecode/Writer.h b/include/llvm/Bytecode/Writer.h
index c87cc928483..d18d82cfc33 100644
--- a/include/llvm/Bytecode/Writer.h
+++ b/include/llvm/Bytecode/Writer.h
@@ -23,7 +23,7 @@ namespace llvm {
   /// stream.  If compress is set to true, try to use compression when writing
   /// out the file.  This can never fail if M is a well-formed module.
   void WriteBytecodeToFile(const Module *M, OStream &Out,
-                           bool compress = true);
+                           bool compress = false);
 } // End llvm namespace
 
 #endif
diff --git a/tools/bugpoint/OptimizerDriver.cpp b/tools/bugpoint/OptimizerDriver.cpp
index 8a19739e285..374de269114 100644
--- a/tools/bugpoint/OptimizerDriver.cpp
+++ b/tools/bugpoint/OptimizerDriver.cpp
@@ -57,7 +57,7 @@ bool BugDriver::writeProgramToFile(const std::string &Filename,
   if (!Out.good()) return true;
   try {
     OStream L(Out);
-    WriteBytecodeToFile(M ? M : Program, L, /*compression=*/true);
+    WriteBytecodeToFile(M ? M : Program, L, /*compression=*/false);
   } catch (...) {
     return true;
   }
diff --git a/tools/gccas/gccas.cpp b/tools/gccas/gccas.cpp
index 587a6a850d8..c102fc581fa 100644
--- a/tools/gccas/gccas.cpp
+++ b/tools/gccas/gccas.cpp
@@ -54,7 +54,7 @@ namespace {
              cl::desc("Strip debugger symbol info from translation unit"));
 
   cl::opt<bool>
-  NoCompress("disable-compression", cl::init(false),
+  NoCompress("disable-compression", cl::init(true),
              cl::desc("Don't compress the generated bytecode"));
 
   cl::opt<bool> TF("traditional-format", cl::Hidden,
diff --git a/tools/gccld/GenerateCode.cpp b/tools/gccld/GenerateCode.cpp
index 13bda75b423..db1caa82709 100644
--- a/tools/gccld/GenerateCode.cpp
+++ b/tools/gccld/GenerateCode.cpp
@@ -42,7 +42,7 @@ namespace {
                        cl::desc("Do not run any optimization passes"));
 
   cl::opt<bool>
-  NoCompress("disable-compression", cl::init(false),
+  NoCompress("disable-compression", cl::init(true),
              cl::desc("Don't compress the generated bytecode"));
 }
 
diff --git a/tools/llvm-as/llvm-as.cpp b/tools/llvm-as/llvm-as.cpp
index dd29bc19e83..e3dbfb46be9 100644
--- a/tools/llvm-as/llvm-as.cpp
+++ b/tools/llvm-as/llvm-as.cpp
@@ -43,7 +43,7 @@ static cl::opt<bool>
 DumpAsm("d", cl::desc("Print assembly as parsed"), cl::Hidden);
 
 static cl::opt<bool>
-NoCompress("disable-compression", cl::init(false),
+NoCompress("disable-compression", cl::init(true),
            cl::desc("Don't compress the generated bytecode"));
 
 static cl::opt<bool>
diff --git a/tools/llvm-ld/llvm-ld.cpp b/tools/llvm-ld/llvm-ld.cpp
index 2e599064a52..6ec0ce7591b 100644
--- a/tools/llvm-ld/llvm-ld.cpp
+++ b/tools/llvm-ld/llvm-ld.cpp
@@ -74,7 +74,7 @@ static cl::opt<bool> Native("native",
 static cl::opt<bool>NativeCBE("native-cbe",
   cl::desc("Generate a native binary with the C backend and GCC"));
 
-static cl::opt<bool>DisableCompression("disable-compression",cl::init(false),
+static cl::opt<bool>DisableCompression("disable-compression", cl::init(true),
   cl::desc("Disable writing of compressed bytecode files"));
 
 static cl::list<std::string> PostLinkOpts("post-link-opts",
diff --git a/tools/llvm-link/llvm-link.cpp b/tools/llvm-link/llvm-link.cpp
index be556d1ed25..343b36cefcd 100644
--- a/tools/llvm-link/llvm-link.cpp
+++ b/tools/llvm-link/llvm-link.cpp
@@ -43,7 +43,7 @@ Verbose("v", cl::desc("Print information about actions taken"));
 static cl::opt<bool>
 DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden);
 
-static cl::opt<bool> NoCompress("disable-compression", cl::init(false),
+static cl::opt<bool> NoCompress("disable-compression", cl::init(true),
        cl::desc("Don't compress the generated bytecode"));
 
 // LoadFile - Read the specified bytecode file in and return it.  This routine
diff --git a/tools/lto/lto.cpp b/tools/lto/lto.cpp
index 383da87a62d..38f01a004a6 100644
--- a/tools/lto/lto.cpp
+++ b/tools/lto/lto.cpp
@@ -364,7 +364,7 @@ LTO::optimizeModules(const std::string &OutputFilename,
     tempFileName += "0.bc";
     std::ofstream Out(tempFileName.c_str(), io_mode);
     OStream L(Out);
-    WriteBytecodeToFile(bigOne, L, true);
+    WriteBytecodeToFile(bigOne, L);
   }
 
   // Strip leading underscore because it was added to match names
@@ -418,7 +418,7 @@ LTO::optimizeModules(const std::string &OutputFilename,
     tempFileName += "1.bc";
     std::ofstream Out(tempFileName.c_str(), io_mode);
     OStream L(Out);
-    WriteBytecodeToFile(bigOne, L, true);
+    WriteBytecodeToFile(bigOne, L);
   }
 
   targetTriple = bigOne->getTargetTriple();
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 7d5dd2113df..d5d6f779dbc 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -41,7 +41,7 @@ using namespace llvm;
 static cl::list<const PassInfo*, bool, PassNameParser>
 PassList(cl::desc("Optimizations available:"));
 
-static cl::opt<bool> NoCompress("disable-compression", cl::init(false),
+static cl::opt<bool> NoCompress("disable-compression", cl::init(true),
        cl::desc("Don't compress the generated bytecode"));
 
 // Other command line options...