diff --git a/llvm/examples/OrcV2Examples/OrcV2CBindingsBasicUsage/OrcV2CBindingsBasicUsage.c b/llvm/examples/OrcV2Examples/OrcV2CBindingsBasicUsage/OrcV2CBindingsBasicUsage.c
--- a/llvm/examples/OrcV2Examples/OrcV2CBindingsBasicUsage/OrcV2CBindingsBasicUsage.c
+++ b/llvm/examples/OrcV2Examples/OrcV2CBindingsBasicUsage/OrcV2CBindingsBasicUsage.c
@@ -67,6 +67,17 @@
   return TSM;
 }
 
+void transform(void *Ctx, LLVMModuleRef Mod, LLVMOrcMaterializationResponsibilityRef MR) {
+  LLVMPassManagerRef PM = LLVMCreatePassManager();
+  // Question @lhames: Do we need to run
+  // - LLVMAddAnalysisPass(TM, PM)
+  // - PM->createTargetInfoTransformInfoWrapperPass
+  // - LLVMAddTargetLibraryInfoByTriple(triple, PM)
+  LLVMAddInstructionCombiningPass(PM);
+  LLVMRunPassManager(PM, Mod);
+  LLVMDisposePassManager(PM);
+}
+
 int main(int argc, char *argv[]) {
 
   int MainResult = 0;
@@ -89,6 +100,12 @@
     }
   }
 
+  // add TransformLayer
+  {
+    LLVMOrcIRTransformLayerRef TL = LLVMOrcLLJITGetIRTransformLayer(J);
+    LLVMOrcLLJITIRTransformLayerSetTransform(TL, *transform, NULL);
+  }
+
   // Create our demo module.
   LLVMOrcThreadSafeModuleRef TSM = createDemoModule();
 
diff --git a/llvm/include/llvm-c/LLJIT.h b/llvm/include/llvm-c/LLJIT.h
--- a/llvm/include/llvm-c/LLJIT.h
+++ b/llvm/include/llvm-c/LLJIT.h
@@ -48,6 +48,16 @@
     *LLVMOrcLLJITBuilderObjectLinkingLayerCreatorFunction)(
     void *Ctx, LLVMOrcExecutionSessionRef ES, const char *Triple);
 
+/**
+ * A function for applying transformations as part of an transform layer.
+ *
+ * Clients can call LLVMOrcLLJITGetIRTransformLayer to obtain the transform
+ * layer of a LLJIT instance, and use LLVMOrcLLJITIRTransformLayerSetTransform
+ * to set the function. This can be used to override the default transform layer.
+ */
+typedef void (*LLVMOrcIRTransformLayerTransformFunction)(
+    void *Ctx, LLVMModuleRef Mod, LLVMOrcMaterializationResponsibilityRef MR);
+
 /**
  * A reference to an orc::LLJITBuilder instance.
  */
@@ -216,6 +226,19 @@
  */
 LLVMOrcObjectLayerRef LLVMOrcLLJITGetObjLinkingLayer(LLVMOrcLLJITRef J);
 
+/**
+ * Returns a non-owning reference to the LLJIT instance's IR transform layer.
+ */
+LLVMOrcIRTransformLayerRef LLVMOrcLLJITGetIRTransformLayer(LLVMOrcLLJITRef J);
+
+/**
+ * Set the transform function of the provided transform layer, passing through a
+ * pointer to user provided context.
+ */
+void LLVMOrcLLJITIRTransformLayerSetTransform(
+    LLVMOrcIRTransformLayerRef TransformLayer,
+    LLVMOrcIRTransformLayerTransformFunction F, void *Ctx);
+
 LLVM_C_EXTERN_C_END
 
 #endif /* LLVM_C_LLJIT_H */
diff --git a/llvm/include/llvm-c/Orc.h b/llvm/include/llvm-c/Orc.h
--- a/llvm/include/llvm-c/Orc.h
+++ b/llvm/include/llvm-c/Orc.h
@@ -315,6 +315,11 @@
  */
 typedef struct LLVMOrcOpaqueObjectLinkingLayer *LLVMOrcObjectLinkingLayerRef;
 
+/**
+ * A reference to an orc::IRTransformLayer instance.
+ */
+typedef struct LLVMOrcOpaqueIRTransformLayer *LLVMOrcIRTransformLayerRef;
+
 /**
  * Attach a custom error reporter function to the ExecutionSession.
  *
diff --git a/llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp b/llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp
--- a/llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp
@@ -93,6 +93,7 @@
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(JITTargetMachineBuilder,
                                    LLVMOrcJITTargetMachineBuilderRef)
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(ObjectLayer, LLVMOrcObjectLayerRef)
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(IRTransformLayer, LLVMOrcIRTransformLayerRef)
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLJITBuilder, LLVMOrcLLJITBuilderRef)
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LLJIT, LLVMOrcLLJITRef)
 
@@ -648,3 +649,21 @@
   reinterpret_cast<RTDyldObjectLinkingLayer *>(unwrap(RTDyldObjLinkingLayer))
       ->registerJITEventListener(*unwrap(Listener));
 }
+
+LLVMOrcIRTransformLayerRef LLVMOrcLLJITGetIRTransformLayer(LLVMOrcLLJITRef J) {
+  return wrap(&unwrap(J)->getIRTransformLayer());
+}
+
+void LLVMOrcLLJITIRTransformLayerSetTransform(
+    LLVMOrcIRTransformLayerRef TransformLayer,
+    LLVMOrcIRTransformLayerTransformFunction F, void *Ctx) {
+  unwrap(TransformLayer)->setTransform(
+      [=](ThreadSafeModule TSM,
+          const MaterializationResponsibility &R) -> Expected<ThreadSafeModule> {
+        TSM.withModuleDo(
+          [=, &R](Module &M) {
+            F(Ctx, wrap(&M), wrap(&R));
+          });
+        return std::move(TSM); // Not a redundant move: fix build on gcc-7.5
+      });
+}