[clang] [clang] Load non-simple lvalue operands of __builtin_bit_cast (PR #231830)

[Hubert Tong via cfe-commits]

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@@ -756,6 +756,10 @@ features cannot lower the translation-unit ABI level;
 - Fixed an assertion failure when `__builtin_object_size` or
   `__builtin_dynamic_object_size` is called with an out-of-range type argument
   during constant evaluation. (#GH225041)
+- Fixed wrong code generation for `__builtin_bit_cast` of a vector element,
+  matrix element, bit-field or global register variable, which read from the
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hubert-reinterpretcast wrote:

Shouldn't `__builtin_bit_cast` apply the reference initialization rules for its second operand? At least the bit-field case would then operand on a non-bit-field temporary.

https://github.com/llvm/llvm-project/pull/231830