[clang] [compiler-rt] [clang][UBSan] Add implicit conversion check for bitfields (PR #75481)

[John McCall via cfe-commits]

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@@ -1097,6 +1112,27 @@ void ScalarExprEmitter::EmitIntegerTruncationCheck(Value *Src, QualType SrcType,
                 {Src, Dst});
 }
 
+static llvm::Value *EmitIsNegativeTestHelper(Value *V, QualType VType,
+                                             const char *Name,
+                                             CGBuilderTy &Builder) {
+  // NOTE: zero value is considered to be non-negative.
+  // Is this value a signed type?
+  bool VSigned = VType->isSignedIntegerOrEnumerationType();
+  llvm::Type *VTy = V->getType();
+  if (!VSigned) {
+    // If the value is unsigned, then it is never negative.
+    // FIXME: can we encounter non-scalar VTy here?
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rjmccall wrote:

No, you cannot.

https://github.com/llvm/llvm-project/pull/75481