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
@@ -413,7 +413,7 @@
   NamedRegionTimer T("discoverStorage", "discover storage", TimerGroupName,
                      TimerGroupDesc, opts::TimeRewrite);
 
-  auto ELF64LEFile = dyn_cast<ELF64LEObjectFile>(InputFile);
+  auto ELF64LEFile = cast<ELF64LEObjectFile>(InputFile);
   const ELFFile<ELF64LE> &Obj = ELF64LEFile->getELFFile();
 
   BC->StartFunctionAddress = Obj.getHeader().e_entry;
@@ -4222,11 +4222,7 @@
 }
 
 void RewriteInstance::patchELFPHDRTable() {
-  auto ELF64LEFile = dyn_cast<ELF64LEObjectFile>(InputFile);
-  if (!ELF64LEFile) {
-    errs() << "BOLT-ERROR: only 64-bit LE ELF binaries are supported\n";
-    exit(1);
-  }
+  auto ELF64LEFile = cast<ELF64LEObjectFile>(InputFile);
   const ELFFile<ELF64LE> &Obj = ELF64LEFile->getELFFile();
   raw_fd_ostream &OS = Out->os();
 
@@ -4375,11 +4371,7 @@
 }
 
 void RewriteInstance::rewriteNoteSections() {
-  auto ELF64LEFile = dyn_cast<ELF64LEObjectFile>(InputFile);
-  if (!ELF64LEFile) {
-    errs() << "BOLT-ERROR: only 64-bit LE ELF binaries are supported\n";
-    exit(1);
-  }
+  auto ELF64LEFile = cast<ELF64LEObjectFile>(InputFile);
   const ELFFile<ELF64LE> &Obj = ELF64LEFile->getELFFile();
   raw_fd_ostream &OS = Out->os();