diff --git a/llvm/tools/llvm-exegesis/lib/Assembler.cpp b/llvm/tools/llvm-exegesis/lib/Assembler.cpp
index bb89655435a8a..523cb913885e7 100644
--- a/llvm/tools/llvm-exegesis/lib/Assembler.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Assembler.cpp
@@ -167,11 +167,11 @@ BitVector getFunctionReservedRegs(const TargetMachine &TM) {
   return MF.getSubtarget().getRegisterInfo()->getReservedRegs(MF);
 }
 
-void assembleToStream(const ExegesisTarget &ET,
-                      std::unique_ptr<LLVMTargetMachine> TM,
-                      ArrayRef<unsigned> LiveIns,
-                      ArrayRef<RegisterValue> RegisterInitialValues,
-                      const FillFunction &Fill, raw_pwrite_stream &AsmStream) {
+Error assembleToStream(const ExegesisTarget &ET,
+                       std::unique_ptr<LLVMTargetMachine> TM,
+                       ArrayRef<unsigned> LiveIns,
+                       ArrayRef<RegisterValue> RegisterInitialValues,
+                       const FillFunction &Fill, raw_pwrite_stream &AsmStream) {
   auto Context = std::make_unique<LLVMContext>();
   std::unique_ptr<Module> Module =
       createModule(Context, TM->createDataLayout());
@@ -234,15 +234,15 @@ void assembleToStream(const ExegesisTarget &ET,
   for (const char *PassName :
        {"postrapseudos", "machineverifier", "prologepilog"})
     if (addPass(PM, PassName, *TPC))
-      report_fatal_error("Unable to add a mandatory pass");
+      return make_error<Failure>("Unable to add a mandatory pass");
   TPC->setInitialized();
 
   // AsmPrinter is responsible for generating the assembly into AsmBuffer.
-  if (TM->addAsmPrinter(PM, AsmStream, nullptr, CGFT_ObjectFile,
-                        MCContext))
-    report_fatal_error("Cannot add AsmPrinter passes");
+  if (TM->addAsmPrinter(PM, AsmStream, nullptr, CGFT_ObjectFile, MCContext))
+    return make_error<Failure>("Cannot add AsmPrinter passes");
 
   PM.run(*Module); // Run all the passes
+  return Error::success();
 }
 
 object::OwningBinary<object::ObjectFile>
diff --git a/llvm/tools/llvm-exegesis/lib/Assembler.h b/llvm/tools/llvm-exegesis/lib/Assembler.h
index 5d4204e4a50ce..2a83344b751e5 100644
--- a/llvm/tools/llvm-exegesis/lib/Assembler.h
+++ b/llvm/tools/llvm-exegesis/lib/Assembler.h
@@ -18,6 +18,7 @@
 #include <memory>
 
 #include "BenchmarkCode.h"
+#include "Error.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/CodeGen/MachineFunction.h"
@@ -86,11 +87,11 @@ using FillFunction = std::function<void(FunctionFiller &)>;
 // Instructions. Runs a set of llvm Passes to provide correct prologue and
 // epilogue. Once the MachineFunction is ready, it is assembled for TM to
 // AsmStream, the temporary function is eventually discarded.
-void assembleToStream(const ExegesisTarget &ET,
-                      std::unique_ptr<LLVMTargetMachine> TM,
-                      ArrayRef<unsigned> LiveIns,
-                      ArrayRef<RegisterValue> RegisterInitialValues,
-                      const FillFunction &Fill, raw_pwrite_stream &AsmStream);
+Error assembleToStream(const ExegesisTarget &ET,
+                       std::unique_ptr<LLVMTargetMachine> TM,
+                       ArrayRef<unsigned> LiveIns,
+                       ArrayRef<RegisterValue> RegisterInitialValues,
+                       const FillFunction &Fill, raw_pwrite_stream &AsmStream);
 
 // Creates an ObjectFile in the format understood by the host.
 // Note: the resulting object keeps a copy of Buffer so it can be discarded once
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index 6981aaa46cd92..5b15bc29c60d3 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -101,10 +101,12 @@ Expected<InstructionBenchmark> BenchmarkRunner::runConfiguration(
   {
     SmallString<0> Buffer;
     raw_svector_ostream OS(Buffer);
-    assembleToStream(State.getExegesisTarget(), State.createTargetMachine(),
-                     BC.LiveIns, BC.Key.RegisterInitialValues,
-                     Repetitor.Repeat(Instructions, kMinInstructionsForSnippet),
-                     OS);
+    if (Error E = assembleToStream(
+            State.getExegesisTarget(), State.createTargetMachine(), BC.LiveIns,
+            BC.Key.RegisterInitialValues,
+            Repetitor.Repeat(Instructions, kMinInstructionsForSnippet), OS)) {
+      return std::move(E);
+    }
     const ExecutableFunction EF(State.createTargetMachine(),
                                 getObjectFromBuffer(OS.str()));
     const auto FnBytes = EF.getFunctionBytes();
@@ -129,8 +131,11 @@ Expected<InstructionBenchmark> BenchmarkRunner::runConfiguration(
   } else {
     SmallString<0> Buffer;
     raw_svector_ostream OS(Buffer);
-    assembleToStream(State.getExegesisTarget(), State.createTargetMachine(),
-                     BC.LiveIns, BC.Key.RegisterInitialValues, Filler, OS);
+    if (Error E = assembleToStream(State.getExegesisTarget(),
+                                   State.createTargetMachine(), BC.LiveIns,
+                                   BC.Key.RegisterInitialValues, Filler, OS)) {
+      return std::move(E);
+    }
     ObjectFile = getObjectFromBuffer(OS.str());
   }
 
@@ -165,8 +170,11 @@ BenchmarkRunner::writeObjectFile(const BenchmarkCode &BC,
           sys::fs::createTemporaryFile("snippet", "o", ResultFD, ResultPath)))
     return std::move(E);
   raw_fd_ostream OFS(ResultFD, true /*ShouldClose*/);
-  assembleToStream(State.getExegesisTarget(), State.createTargetMachine(),
-                   BC.LiveIns, BC.Key.RegisterInitialValues, FillFunction, OFS);
+  if (Error E = assembleToStream(
+          State.getExegesisTarget(), State.createTargetMachine(), BC.LiveIns,
+          BC.Key.RegisterInitialValues, FillFunction, OFS)) {
+    return std::move(E);
+  }
   return std::string(ResultPath.str());
 }
 
diff --git a/llvm/unittests/tools/llvm-exegesis/Common/AssemblerUtils.h b/llvm/unittests/tools/llvm-exegesis/Common/AssemblerUtils.h
index 795b0d6ab64b2..239685beb14e9 100644
--- a/llvm/unittests/tools/llvm-exegesis/Common/AssemblerUtils.h
+++ b/llvm/unittests/tools/llvm-exegesis/Common/AssemblerUtils.h
@@ -77,8 +77,8 @@ class MachineFunctionGeneratorBaseTest : public ::testing::Test {
                      FillFunction Fill) {
     SmallString<256> Buffer;
     raw_svector_ostream AsmStream(Buffer);
-    assembleToStream(*ET, createTargetMachine(), /*LiveIns=*/{},
-                     RegisterInitialValues, Fill, AsmStream);
+    EXPECT_FALSE(assembleToStream(*ET, createTargetMachine(), /*LiveIns=*/{},
+                                  RegisterInitialValues, Fill, AsmStream));
     return ExecutableFunction(createTargetMachine(),
                               getObjectFromBuffer(AsmStream.str()));
   }