[clang] [CIR][SPIR-V] Keep atomic sync scopes (PR #231754)

[Steffen Larsen via cfe-commits]

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@@ -27,7 +27,12 @@ constexpr unsigned SPIRVAddrSpaceMap[] = {
 };
 
 class SPIRVTargetLoweringInfo : public TargetLoweringInfo {
+  // SPIR keeps the default system scope, like CommonSPIRTargetCodeGenInfo.
+  bool isSPIRV;
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steffenlarsen wrote:

Reads a little weird that something called `SPIRVTargetLoweringInfo` is not SPIR-V. Would it make sense to invert the bool, i.e. make it `isSPIR`, or rename the `SPIRVTargetLoweringInfo` to `SPIRTargetLoweringInfo`?

Alternatively, should we consider splitting `SPIRVTargetLoweringInfo` into two, so `SPIR` gets it own and we either make `SPIRVTargetLoweringInfo` inherit from it or make a common base class and diverge the behavior only when required through overriding?

https://github.com/llvm/llvm-project/pull/231754