[irgen] Refactor llvm intrinsic emission out of emitBuiltinCall.

This simplifies the function and will make it easier for me to convert the
function into an exhaustive switch with an NFC commit.

Author: gottesmm

lib/IRGen/GenBuiltin.cpp

@@ -129,13 +129,71 @@ getMaximallyAbstractedLoweredTypeAndTypeInfo(IRGenModule &IGM, Type unloweredTyp
   return {lowered, IGM.getTypeInfo(lowered)};
 }
 
+static bool emitLLVMIRIntrinsicCall(IRGenFunction &IGF, Identifier FnID,
+                                    Explosion &args, Explosion &out) {
+  const IntrinsicInfo &IInfo = IGF.getSILModule().getIntrinsicInfo(FnID);
+  llvm::Intrinsic::ID IID = IInfo.ID;
+
+  if (IID == llvm::Intrinsic::not_intrinsic)
+    return false;
+
+  // Emit non-mergeable traps only.
+  if (IGF.Builder.isTrapIntrinsic(IID)) {
+    IGF.Builder.CreateNonMergeableTrap(IGF.IGM, StringRef());
+    return true;
+  }
+
+  // Implement the ptrauth builtins as no-ops when the Clang
+  // intrinsics are disabled.
+  if ((IID == llvm::Intrinsic::ptrauth_sign ||
+       IID == llvm::Intrinsic::ptrauth_auth ||
+       IID == llvm::Intrinsic::ptrauth_resign ||
+       IID == llvm::Intrinsic::ptrauth_strip) &&
+      !IGF.IGM.getClangASTContext().getLangOpts().PointerAuthIntrinsics) {
+    out.add(args.claimNext()); // Return the input pointer.
+    (void)args.claimNext();    // Ignore the key.
+    if (IID != llvm::Intrinsic::ptrauth_strip) {
+      (void)args.claimNext(); // Ignore the discriminator.
+    }
+    if (IID == llvm::Intrinsic::ptrauth_resign) {
+      (void)args.claimNext(); // Ignore the new key.
+      (void)args.claimNext(); // Ignore the new discriminator.
+    }
+    return true;
+  }
+
+  SmallVector<llvm::Type *, 4> ArgTys;
+  for (auto T : IInfo.Types)
+    ArgTys.push_back(IGF.IGM.getStorageTypeForLowered(T->getCanonicalType()));
+
+  auto F = llvm::Intrinsic::getOrInsertDeclaration(
+      &IGF.IGM.Module, (llvm::Intrinsic::ID)IID, ArgTys);
+  llvm::FunctionType *FT = F->getFunctionType();
+  SmallVector<llvm::Value *, 8> IRArgs;
+  for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
+    IRArgs.push_back(args.claimNext());
+  llvm::Value *TheCall =
+      IGF.Builder.CreateIntrinsicCall((llvm::Intrinsic::ID)IID, ArgTys, IRArgs);
+
+  if (!TheCall->getType()->isVoidTy())
+    extractScalarResults(IGF, TheCall->getType(), TheCall, out);
+
+  return true;
+}
+
 /// emitBuiltinCall - Emit a call to a builtin function.
 void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
                             BuiltinInst *Inst, ArrayRef<SILType> argTypes,
                             Explosion &args, Explosion &out) {
   auto &IGM = IGF.IGM;
 
   Identifier FnId = Inst->getName();
+
+  // Before we do anything, lets see if we have an LLVM IR Intrinsic Call. If we
+  // did, we can return early.
+  if (emitLLVMIRIntrinsicCall(IGF, FnId, args, out))
+    return;
+
   SILType resultType = Inst->getType();
   SubstitutionMap substitutions = Inst->getSubstitutions();
 
@@ -413,55 +471,6 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     return;
   }
 
-  // If this is an LLVM IR intrinsic, lower it to an intrinsic call.
-  const IntrinsicInfo &IInfo = IGF.getSILModule().getIntrinsicInfo(FnId);
-  llvm::Intrinsic::ID IID = IInfo.ID;
-
-  // Emit non-mergeable traps only.
-  if (IGF.Builder.isTrapIntrinsic(IID)) {
-    IGF.Builder.CreateNonMergeableTrap(IGF.IGM, StringRef());
-    return;
-  }
-
-  // Implement the ptrauth builtins as no-ops when the Clang
-  // intrinsics are disabled.
-  if ((IID == llvm::Intrinsic::ptrauth_sign ||
-       IID == llvm::Intrinsic::ptrauth_auth ||
-       IID == llvm::Intrinsic::ptrauth_resign ||
-       IID == llvm::Intrinsic::ptrauth_strip) &&
-      !IGF.IGM.getClangASTContext().getLangOpts().PointerAuthIntrinsics) {
-    out.add(args.claimNext()); // Return the input pointer.
-    (void) args.claimNext();   // Ignore the key.
-    if (IID != llvm::Intrinsic::ptrauth_strip) {
-      (void) args.claimNext(); // Ignore the discriminator.
-    }
-    if (IID == llvm::Intrinsic::ptrauth_resign) {
-      (void) args.claimNext(); // Ignore the new key.
-      (void) args.claimNext(); // Ignore the new discriminator.
-    }
-    return;
-  }
-
-  if (IID != llvm::Intrinsic::not_intrinsic) {
-    SmallVector<llvm::Type*, 4> ArgTys;
-    for (auto T : IInfo.Types)
-      ArgTys.push_back(IGF.IGM.getStorageTypeForLowered(T->getCanonicalType()));
-
-    auto F = llvm::Intrinsic::getOrInsertDeclaration(
-        &IGF.IGM.Module, (llvm::Intrinsic::ID)IID, ArgTys);
-    llvm::FunctionType *FT = F->getFunctionType();
-    SmallVector<llvm::Value*, 8> IRArgs;
-    for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
-      IRArgs.push_back(args.claimNext());
-    llvm::Value *TheCall = IGF.Builder.CreateIntrinsicCall(
-        (llvm::Intrinsic::ID)IID, ArgTys, IRArgs);
-
-    if (!TheCall->getType()->isVoidTy())
-      extractScalarResults(IGF, TheCall->getType(), TheCall, out);
-
-    return;
-  }
-
   if (Builtin.ID == BuiltinValueKind::StringObjectOr) {
     llvm::Value *lhs = args.claimNext();
     llvm::Value *rhs = args.claimNext();