[clang] 5594d12 - [clang][driver] NFC: Upstream comment

[Jan Svoboda via cfe-commits]

Author: Jan Svoboda
Date: 2024-03-01T16:53:12-08:00
New Revision: 5594d12af540dfcc684a02a232484c2b4dd2f5b5

URL: https://github.com/llvm/llvm-project/commit/5594d12af540dfcc684a02a232484c2b4dd2f5b5
DIFF: https://github.com/llvm/llvm-project/commit/5594d12af540dfcc684a02a232484c2b4dd2f5b5.diff

LOG: [clang][driver] NFC: Upstream comment

Added: 
    

Modified: 
    clang/lib/Driver/ToolChains/Arch/AArch64.cpp

Removed: 
    


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diff  --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
index 0cf96bb5c9cb02..aa3b80cb16e55a 100644
--- a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -165,11 +165,14 @@ getAArch64MicroArchFeaturesFromMtune(const Driver &D, StringRef Mtune,
   // Handle CPU name is 'native'.
   if (MtuneLowerCase == "native")
     MtuneLowerCase = std::string(llvm::sys::getHostCPUName());
+
+  // 'cyclone' and later have zero-cycle register moves and zeroing.
   if (MtuneLowerCase == "cyclone" ||
       StringRef(MtuneLowerCase).starts_with("apple")) {
     Features.push_back("+zcm");
     Features.push_back("+zcz");
   }
+
   return true;
 }