[clang] [clang] Better bitfield access units (PR #65742)

[Lu Weining via cfe-commits]

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@@ -132,6 +132,7 @@ class LLVM_LIBRARY_VISIBILITY LoongArch64TargetInfo
       : LoongArchTargetInfo(Triple, Opts) {
     LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
     IntMaxType = Int64Type = SignedLong;
+    HasCheapUnalignedBitfieldAccess = true;
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SixWeining wrote:

> Only set it to true when -mno-unaligned-access.

In `LoongArchTargetInfo::handleTargetFeatures()`, we can handle the feature `-ual`.

https://github.com/llvm/llvm-project/pull/65742