Add in new pass removed from InstCombine in refactor

Upstream LLVM refactored InstCombine to extract a new InferAlignment pass which
needs adding back in to the passes being run.

lgc/patch/Patch.cpp

@@ -86,6 +86,7 @@
 #include "llvm/Transforms/Scalar/EarlyCSE.h"
 #include "llvm/Transforms/Scalar/GVN.h"
 #include "llvm/Transforms/Scalar/IndVarSimplify.h"
+#include "llvm/Transforms/Scalar/InferAlignment.h"
 #include "llvm/Transforms/Scalar/InstSimplifyPass.h"
 #include "llvm/Transforms/Scalar/LICM.h"
 #include "llvm/Transforms/Scalar/LoopDeletion.h"
@@ -106,6 +107,10 @@
 
 using namespace llvm;
 
+namespace llvm {
+extern cl::opt<bool> EnableInferAlignmentPass;
+} // namespace llvm
+
 namespace lgc {
 
 // =====================================================================================================================
@@ -410,6 +415,8 @@ void Patch::addOptimizationPasses(lgc::PassManager &passMgr, uint32_t optLevel)
   fpm.addPass(SROAPass(SROAOptions::ModifyCFG));
   // uses UniformityAnalysis
   fpm.addPass(PatchReadFirstLane());
+  if (EnableInferAlignmentPass)
+    fpm.addPass(InferAlignmentPass());
   fpm.addPass(InstCombinePass());
   passMgr.addPass(createModuleToFunctionPassAdaptor(std::move(fpm)));
   passMgr.addPass(ConstantMergePass());