[llvm] [LoongArch] Introduce `32s` target feature for LA32S ISA extensions (PR #139695)

[WÁNG Xuěruì via llvm-commits]

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@@ -854,6 +854,12 @@ def BREAK   : MISC_I15<0x002a0000>;
 def RDTIMEL_W : RDTIME_2R<0x00006000>;
 def RDTIMEH_W : RDTIME_2R<0x00006400>;
 
+// The CPUCFG instruction offers a reliable way to probing CPU features.
+// Although it's undefined on LA32R, adding compiler support enables the
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xen0n wrote:

Maybe this is better: "Although support is not guaranteed on LA32R, having compiler support nevertheless enables ..."

(Apparently it's not forbidden to have it included in a LA32R implementation, it's just not being in the mandatory set.)

https://github.com/llvm/llvm-project/pull/139695