diff --git a/constantine/platforms/code_generator/bindings/llvm_abi.nim b/constantine/platforms/code_generator/bindings/llvm_abi.nim
index 27c839d..4927c13 100644
--- a/constantine/platforms/code_generator/bindings/llvm_abi.nim
+++ b/constantine/platforms/code_generator/bindings/llvm_abi.nim
@@ -248,16 +248,20 @@ proc getGlobalPassRegistry(): PassRegistryRef {.importc: "LLVMGetGlobalPassRegis
 proc initializeCore(registry: PassRegistryRef) {.importc: "LLVMInitializeCore".}
 proc initializeTransformUtils(registry: PassRegistryRef) {.importc: "LLVMInitializeTransformUtils".}
 proc initializeScalarOpts(registry: PassRegistryRef) {.importc: "LLVMInitializeScalarOpts".}
-proc initializeObjCARCOpts(registry: PassRegistryRef) {.importc: "LLVMInitializeObjCARCOpts".}
 proc initializeVectorization(registry: PassRegistryRef) {.importc: "LLVMInitializeVectorization".}
 proc initializeInstCombine(registry: PassRegistryRef) {.importc: "LLVMInitializeInstCombine".}
-proc initializeAggressiveInstCombiner(registry: PassRegistryRef) {.importc: "LLVMInitializeAggressiveInstCombiner".}
 proc initializeIPO(registry: PassRegistryRef) {.importc: "LLVMInitializeIPO".}
-proc initializeInstrumentation(registry: PassRegistryRef) {.importc: "LLVMInitializeInstrumentation".}
 proc initializeAnalysis(registry: PassRegistryRef) {.importc: "LLVMInitializeAnalysis".}
 proc initializeIPA(registry: PassRegistryRef) {.importc: "LLVMInitializeIPA".}
 proc initializeCodeGen(registry: PassRegistryRef) {.importc: "LLVMInitializeCodeGen".}
 proc initializeTarget(registry: PassRegistryRef) {.importc: "LLVMInitializeTarget".}
+
+# Removed in LLVM 16
+# ------------------
+# proc initializeObjCARCOpts(registry: PassRegistryRef) {.importc: "LLVMInitializeObjCARCOpts".}
+# proc initializeAggressiveInstCombiner(registry: PassRegistryRef) {.importc: "LLVMInitializeAggressiveInstCombiner".}
+# proc initializeInstrumentation(registry: PassRegistryRef) {.importc: "LLVMInitializeInstrumentation".}
+
 {.pop.}
 
 # https://llvm.org/doxygen/group__LLVMCTarget.html
diff --git a/constantine/platforms/code_generator/ir.nim b/constantine/platforms/code_generator/ir.nim
index 50805be..32d6e16 100644
--- a/constantine/platforms/code_generator/ir.nim
+++ b/constantine/platforms/code_generator/ir.nim
@@ -10,7 +10,7 @@ import
   ../../math/config/[curves, precompute],
   ../../math/io/io_bigints,
   ../primitives, ../bithacks,
-  ../../serialization/[endians, codecs],
+  ../../serialization/[endians, codecs, io_limbs],
   ./llvm
 
 # ############################################################
diff --git a/constantine/platforms/code_generator/llvm.nim b/constantine/platforms/code_generator/llvm.nim
index 4f37557..39e106f 100644
--- a/constantine/platforms/code_generator/llvm.nim
+++ b/constantine/platforms/code_generator/llvm.nim
@@ -120,7 +120,7 @@ template emitToFile*(t: TargetMachineRef, m: ModuleRef,
     writeStackTrace()
     stderr.write("\"emitToFile\" for module '" & astToStr(module) & "' " & $instantiationInfo() & " exited with error: " & $cstring(errMsg) & '\n')
     errMsg.dispose()
-    quit 1 
+    quit 1
 
 template emitToString*(t: TargetMachineRef, m: ModuleRef, codegen: CodeGenFileType): string =
   ## Codegen to string
@@ -147,17 +147,20 @@ proc initializePasses* =
   registry.initializeCore()
   registry.initializeTransformUtils()
   registry.initializeScalarOpts()
-  registry.initializeObjCARCOpts()
   registry.initializeVectorization()
   registry.initializeInstCombine()
-  registry.initializeAggressiveInstCombiner()
   registry.initializeIPO()
-  registry.initializeInstrumentation()
   registry.initializeAnalysis()
   registry.initializeIPA()
   registry.initializeCodeGen()
   registry.initializeTarget()
 
+  # Removed in LLVM 16
+  # --------------------------------
+  # registry.initializeObjCARCOpts()
+  # registry.initializeAggressiveInstCombiner()
+  # registry.initializeInstrumentation()
+
 # Builder
 # ------------------------------------------------------------
 
diff --git a/constantine/platforms/code_generator/nvidia_inlineasm.nim b/constantine/platforms/code_generator/nvidia_inlineasm.nim
index b17bd89..7406319 100644
--- a/constantine/platforms/code_generator/nvidia_inlineasm.nim
+++ b/constantine/platforms/code_generator/nvidia_inlineasm.nim
@@ -96,7 +96,7 @@ macro genInstr(body: untyped): untyped =
     let lhs = op[2][0][3][0]
 
     instrBody.add quote do:
-      let `ctx` = builder.getContext()
+      let `ctx` {.used.} = builder.getContext()
       # lhs: ValueRef or uint32 or uint64
       let `numBits` = when `lhs` is ValueRef|ConstValueRef: `lhs`.getTypeOf().getIntTypeWidth()
                       else: 8*sizeof(`lhs`)
@@ -226,13 +226,11 @@ macro genInstr(body: untyped): untyped =
     for op in operands:
       # when op is ValueRef: op
       # else: constInt(uint64(op))
-      opArray.add newCall(
-        bindSym"ValueRef",
-        nnkWhenStmt.newTree(
-          nnkElifBranch.newTree(nnkInfix.newTree(ident"is", op, bindSym"AnyValueRef"), op),
-          nnkElse.newTree(newCall(ident"constInt", regTy, newCall(ident"uint64", op)))
+      opArray.add nnkWhenStmt.newTree(
+          nnkElifBranch.newTree(nnkInfix.newTree(ident"is", op, bindSym"ValueRef"), op),
+          nnkElifBranch.newTree(nnkInfix.newTree(ident"is", op, bindSym"ConstValueRef"), newCall(ident"ValueRef", op)),
+          nnkElse.newTree(newCall(ident"ValueRef", newCall(ident"constInt", regTy, newCall(ident"uint64", op))))
         )
-      )
     # builder.call2(ty, inlineASM, [lhs, rhs], name)
     instrBody.add newCall(
       ident"call2", ident"builder", fnTy,