[llvm] [clang] [RISCV][MC] Add experimental support of Zaamo and Zalrsc (PR #78970)

[Craig Topper via cfe-commits]

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@@ -176,6 +188,18 @@ def HasStdExtZacas : Predicate<"Subtarget->hasStdExtZacas()">,
                                "'Zacas' (Atomic Compare-And-Swap Instructions)">;
 def NoStdExtZacas : Predicate<"!Subtarget->hasStdExtZacas()">;
 
+def FeatureStdExtZalrsc
+    : SubtargetFeature<"experimental-zalrsc", "HasStdExtZalrsc", "true",
+                       "'Zalrsc' (Load-Reserved/Store-Conditional)">;
+def HasStdExtZalrsc : Predicate<"Subtarget->hasStdExtZalrsc()">,
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topperc wrote:

This isn't used

https://github.com/llvm/llvm-project/pull/78970