[clang] [llvm] [NFC][AMDGPU] Rename "amdgpu-as" to "amdgpu-synchronize-as" (PR #148627)

[Matt Arsenault via llvm-commits]

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@@ -704,12 +704,12 @@ void diagnoseUnknownMMRAASName(const MachineInstr &MI, StringRef AS) {
       DiagnosticInfoUnsupported(Fn, Str.str(), MI.getDebugLoc(), DS_Warning));
 }
 
-/// Reads \p MI's MMRAs to parse the "amdgpu-as" MMRA.
+/// Reads \p MI's MMRAs to parse the "amdgpu-synchronize-as" MMRA.
 /// If this tag isn't present, or if it has no meaningful values, returns \p
 /// Default. Otherwise returns all the address spaces concerned by the MMRA.
 static SIAtomicAddrSpace getFenceAddrSpaceMMRA(const MachineInstr &MI,
                                                SIAtomicAddrSpace Default) {
-  static constexpr StringLiteral FenceASPrefix = "amdgpu-as";
+  static constexpr StringLiteral FenceASPrefix = "amdgpu-synchronize-as";
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arsenm wrote:

it's droppable metadata, we don't need to worry about auto upgrade 

https://github.com/llvm/llvm-project/pull/148627