[clang] [llvm] [RISCV][MC] Add experimental `Zvvmm` MC support (PR #193956)

[Pengcheng Wang via cfe-commits]

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@@ -0,0 +1,11 @@
+# RUN: llvm-mc -triple=riscv64 -show-encoding --mattr=+experimental-zvvmm %s \
+# RUN:        | FileCheck %s --check-prefixes=CHECK-ENCODING,CHECK-INST
+
+# SEW=32, LMUL=1, ta, ma, lambda=4, altfmt_A=1, altfmt_B=1.
+li t1, 0x3c000000000000d0
+vsetvl t0, a0, t1
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wangpc-pp wrote:

This test and the rv32 one don't increase test coverage actually because `li`+`vsetvl` are not special here. I haven't checked the details of `Zvvmm`, do we have a special syntax for `vset(i)vli` to specify the `lambda` field?

https://github.com/llvm/llvm-project/pull/193956