[clang] [RISCV] Support predefined marcro __riscv_misaligned_{fast,avoid}. (PR #65756)

[Jessica Clarke via cfe-commits]

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@@ -322,6 +327,8 @@ bool RISCVTargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
   if (ISAInfo->hasExtension("zfh") || ISAInfo->hasExtension("zhinx"))
     HasLegalHalfType = true;
 
+  FastUnalignedAccess = llvm::is_contained(Features, "+unaligned-scalar-mem");
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jrtc27 wrote:

What about --target-features +unaligned-scalar-mem --target-features -unaligned-scalar-mem? Unless this has been canonicalised you don't know it's not overridden.

https://github.com/llvm/llvm-project/pull/65756