[clang] [NFC][BoundsSafety] Fold a dyn_cast + assert, and sink to first use (PR #194847)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Hans Wennborg (zmodem)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/194847.diff


1 Files Affected:

- (modified) clang/lib/Sema/SemaDeclAttr.cpp (+1-3) 


``````````diff
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 76073ed80175f..690016ea1bbb5 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -6899,9 +6899,6 @@ static void handleNoPFPAttrField(Sema &S, Decl *D, const ParsedAttr &AL) {
 }
 
 static void handleCountedByAttrField(Sema &S, Decl *D, const ParsedAttr &AL) {
-  auto *FD = dyn_cast<FieldDecl>(D);
-  assert(FD);
-
   auto *CountExpr = AL.getArgAsExpr(0);
   if (!CountExpr)
     return;
@@ -6929,6 +6926,7 @@ static void handleCountedByAttrField(Sema &S, Decl *D, const ParsedAttr &AL) {
     llvm_unreachable("unexpected counted_by family attribute");
   }
 
+  FieldDecl *FD = cast<FieldDecl>(D);
   if (S.CheckCountedByAttrOnField(FD, CountExpr, CountInBytes, OrNull))
     return;
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/194847