[NFC] Add a utility function for testing for a specific BuiltinInst

Author: rjmccall

include/swift/SIL/OwnershipUseVisitor.h

@@ -313,9 +313,7 @@ bool OwnershipUseVisitor<Impl>::visitInnerBorrowScopeEnd(Operand *borrowEnd) {
     return handleUsePoint(borrowEnd, UseLifetimeConstraint::NonLifetimeEnding);
   }
   case OperandOwnership::InstantaneousUse: {
-    auto builtinUser = dyn_cast<BuiltinInst>(borrowEnd->getUser());
-    if (builtinUser && builtinUser->getBuiltinKind() ==
-                           BuiltinValueKind::EndAsyncLetLifetime) {
+    if (isBuiltinInst(borrowEnd->getUser(), BuiltinValueKind::EndAsyncLetLifetime)) {
       return handleUsePoint(borrowEnd,
                             UseLifetimeConstraint::NonLifetimeEnding);
     }

include/swift/SIL/SILInstruction.h

@@ -4309,6 +4309,33 @@ class BuiltinInst final
   }
 };
 
+inline BuiltinInst *isBuiltinInst(SILValue value,
+                                  BuiltinValueKind kind) {
+  if (auto bi = dyn_cast<BuiltinInst>(value)) {
+    if (bi->getBuiltinKind() == kind)
+      return bi;
+  }
+  return nullptr;
+}
+
+inline BuiltinInst *isBuiltinInst(SILInstruction *inst,
+                                  BuiltinValueKind kind) {
+  if (auto bi = dyn_cast<BuiltinInst>(inst)) {
+    if (bi->getBuiltinKind() == kind)
+      return bi;
+  }
+  return nullptr;
+}
+
+inline const BuiltinInst *isBuiltinInst(const SILInstruction *inst,
+                                        BuiltinValueKind kind) {
+  if (auto bi = dyn_cast<BuiltinInst>(inst)) {
+    if (bi->getBuiltinKind() == kind)
+      return bi;
+  }
+  return nullptr;
+}
+
 /// Increments a given profiler counter for a given PGO function name. This is
 /// lowered to the \c llvm.instrprof.increment LLVM intrinsic.
 class IncrementProfilerCounterInst final

lib/SIL/IR/SILInstruction.cpp

@@ -1525,13 +1525,9 @@ bool SILInstruction::isTriviallyDuplicatable() const {
 }
 
 bool SILInstruction::mayTrap() const {
-  if (auto *BI = dyn_cast<BuiltinInst>(this)) {
-    if (auto Kind = BI->getBuiltinKind()) {
-      if (Kind.value() == BuiltinValueKind::WillThrow) {
-        // We don't want willThrow instructions to be removed.
-        return true;
-      }
-    }
+  if (isBuiltinInst(this, BuiltinValueKind::WillThrow)) {
+    // We don't want willThrow instructions to be removed.
+    return true;
   }
   switch(getKind()) {
   case SILInstructionKind::CondFailInst:

lib/SIL/Utils/OwnershipUtils.cpp

@@ -734,9 +734,7 @@ bool BorrowingOperand::visitScopeEndingUses(
     bool dead = true;
     for (auto *use : user->getUses()) {
       dead = false;
-      auto builtinUser = dyn_cast<BuiltinInst>(use->getUser());
-      if (!builtinUser
-          || builtinUser->getBuiltinKind() != BuiltinValueKind::EndAsyncLetLifetime)
+      if (!isBuiltinInst(use->getUser(), BuiltinValueKind::EndAsyncLetLifetime))
         continue;
 
       if (!visitScopeEnd(use)) {