Fix LLVM update from google3

This CL imports a google3 fix for LLVM:
https://critique.corp.google.com/cl/494101670/depot/google3/third_party/swiftshader/src/Reactor/LLVMJIT.cpp

Bug: b/191050320
Change-Id: I1250459354dd8e783352f9acfaf59821be2a84f0
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/70328
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Commit-Queue: Alexis Hétu <sugoi@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/Reactor/LLVMJIT.cpp b/src/Reactor/LLVMJIT.cpp
index d3dbdb9..fad747a 100644
--- a/src/Reactor/LLVMJIT.cpp
+++ b/src/Reactor/LLVMJIT.cpp
@@ -922,7 +922,7 @@
 
 	if(optimizationLevel > 0)
 	{
-		fpm.addPass(llvm::SROAPass());
+		fpm.addPass(llvm::SROAPass(llvm::SROAOptions::PreserveCFG));
 		fpm.addPass(llvm::InstCombinePass());
 	}