[llvm] [RISCV] Support XSfmm LLVM IR and CodeGen (PR #143069)

[Brandon Wu via llvm-commits]

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@@ -180,4 +180,99 @@ let TargetPrefix = "riscv" in {
   // XSfvfnrclipxfqf
   defm int_riscv_sf_vfnrclip_x_f_qf : RISCVSFCustomVFNRCLIP;
   defm int_riscv_sf_vfnrclip_xu_f_qf : RISCVSFCustomVFNRCLIP;
+
+  // XSfmm
+  // Output: (output_len)
+  // Input: (input_len, vsew, twiden)
+  class RISCVSFVSet
+      : DefaultAttrsIntrinsic<[llvm_anyint_ty],
+                              [LLVMMatchType<0>, LLVMMatchType<0>, LLVMMatchType<0>],
+                              [ImmArg<ArgIndex<1>>, ImmArg<ArgIndex<2>>, IntrNoMem]>;
+
+  // Input: (tss, base, tn)
+  // IntrReadMem, IntrHasSideEffects does not work for pattern matching.
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4vtomat wrote:

Oh I probably mean we don't use pattern matching here because IntrReadMem + IntrHasSideEffects doesn't work properly, it's eliminated during instruction selection.
I'll keep `IntrHasSideEffects` anyways lol

https://github.com/llvm/llvm-project/pull/143069