[llvm] [RISCV] Initial codegen support for the XRivosVizip extension (PR #131933)

[Philip Reames via llvm-commits]

================
@@ -124,6 +199,10 @@ define <4 x i32> @zipeven_v4i32_single(<4 x i32> %a) {
 ; CHECK-LABEL: zipeven_v4i32_single:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    ret
+;
+; ZIP-LABEL: zipeven_v4i32_single:
+; ZIP:       # %bb.0: # %entry
----------------
preames wrote:

Actually, rereading, it's not broken.  It's testing the case where we could match a zipeven with an undef second operand.  That happens to also be an identity shuffle, and it's testing we *don't* generate a vzipeven instruction for that case.  I'll add a comment to make that clear.

https://github.com/llvm/llvm-project/pull/131933