diff --git a/opt.cpp b/opt.cpp
index b2ddab06..c37c822f 100644
--- a/opt.cpp
+++ b/opt.cpp
@@ -612,7 +612,11 @@ Optimize(llvm::Module *module, int optLevel) {
         optPM.add(llvm::createBasicAAWrapperPass());
 #endif
         optPM.add(llvm::createCFGSimplificationPass());
+#if ISPC_LLVM_VERSION <= ISPC_LLVM_3_6
+        optPM.add(llvm::createScalarReplAggregatesPass());
+#else
         optPM.add(llvm::createSROAPass());
+#endif
         optPM.add(llvm::createEarlyCSEPass());
         optPM.add(llvm::createLowerExpectIntrinsicPass());
 
@@ -641,11 +645,17 @@ Optimize(llvm::Module *module, int optLevel) {
         // Max struct size threshold for scalar replacement is
         //    1) 4 fields (r,g,b,w)
         //    2) field size: vectorWidth * sizeof(float)
+#if ISPC_LLVM_VERSION <= ISPC_LLVM_3_6        
         const int field_limit = 4;
         int sr_threshold = g->target->getVectorWidth() * sizeof(float) * field_limit;
+#endif
 
         // On to more serious optimizations
+#if ISPC_LLVM_VERSION <= ISPC_LLVM_3_6
         optPM.add(llvm::createScalarReplAggregatesPass(sr_threshold));
+#else
+        optPM.add(llvm::createSROAPass());
+#endif
         optPM.add(llvm::createInstructionCombiningPass());
         optPM.add(llvm::createCFGSimplificationPass());
         optPM.add(llvm::createPromoteMemoryToRegisterPass());
@@ -678,7 +688,11 @@ Optimize(llvm::Module *module, int optLevel) {
         optPM.add(llvm::createInstructionCombiningPass(), 241);
         optPM.add(llvm::createJumpThreadingPass());
         optPM.add(llvm::createCFGSimplificationPass());
+#if ISPC_LLVM_VERSION <= ISPC_LLVM_3_6
         optPM.add(llvm::createScalarReplAggregatesPass(sr_threshold));
+#else
+        optPM.add(llvm::createSROAPass());
+#endif        
         optPM.add(llvm::createInstructionCombiningPass());
         optPM.add(llvm::createTailCallEliminationPass());
 
@@ -726,7 +740,11 @@ Optimize(llvm::Module *module, int optLevel) {
 
         optPM.add(llvm::createFunctionInliningPass());
         optPM.add(llvm::createArgumentPromotionPass());
-        optPM.add(llvm::createScalarReplAggregatesPass(sr_threshold, false));
+#if ISPC_LLVM_VERSION <= ISPC_LLVM_3_6
+        optPM.add(llvm::createScalarReplAggregatesPass(sr_threshold));
+#else
+        optPM.add(llvm::createSROAPass());
+#endif        
         optPM.add(llvm::createInstructionCombiningPass());
         optPM.add(CreateInstructionSimplifyPass());
         optPM.add(llvm::createCFGSimplificationPass());
@@ -780,7 +798,11 @@ Optimize(llvm::Module *module, int optLevel) {
           optPM.add(llvm::createCFGSimplificationPass());
           // Here clang has an experimental pass SROAPass instead of
           // ScalarReplAggregatesPass. We should add it in the future.
-          optPM.add(llvm::createScalarReplAggregatesPass());
+#if ISPC_LLVM_VERSION <= ISPC_LLVM_3_6
+          optPM.add(llvm::createScalarReplAggregatesPass(sr_threshold));
+#else
+          optPM.add(llvm::createSROAPass());
+#endif          
           optPM.add(llvm::createEarlyCSEPass());
           optPM.add(llvm::createLowerExpectIntrinsicPass());
           optPM.add(llvm::createTypeBasedAliasAnalysisPass());