[clang] [llvm] [RISCV] Add support for RISC-V Pointer Masking (PR #79929)

[Craig Topper via cfe-commits]

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@@ -797,6 +797,40 @@ def FeatureStdExtSvpbmt
     : SubtargetFeature<"svpbmt", "HasStdExtSvpbmt", "true",
                        "'Svpbmt' (Page-Based Memory Types)">;
 
+// Pointer Masking extensions
+
+// A supervisor-level extension that provides pointer masking for the next lower
+// privilege mode (U-mode), and for VS- and VU-modes if the H extension is
+// present.
+def FeatureStdExtSsnpm
+    : SubtargetFeature<"experimental-ssnpm", "HasStdExtSsnpm", "true",
+                       "'Ssnpm' (Supervisor-level Pointer Masking)">;
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topperc wrote:

Please add "for Next Lower Privilege Level" to ssnpm and smnpm description. I think that's important and the meaning of the 'n' in the extension name.

https://github.com/llvm/llvm-project/pull/79929