[RISCV] Add test case for exact vscale miscompile in llvm#90559. NFC

Author: lukel97

llvm/test/CodeGen/RISCV/rvv/pr90559.ll

@@ -0,0 +1,23 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc < %s -mtriple=riscv64 -mattr=+v | FileCheck %s
+
+; FIXME: The i32 load and store pair isn't dead and shouldn't be omitted.
+define void @f(ptr %p) vscale_range(2,2) {
+; CHECK-LABEL: f:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vsetvli a1, zero, e8, m4, ta, ma
+; CHECK-NEXT:    vmv.v.i v8, 0
+; CHECK-NEXT:    vs4r.v v8, (a0)
+; CHECK-NEXT:    addi a1, a0, 80
+; CHECK-NEXT:    vsetivli zero, 16, e8, m1, ta, ma
+; CHECK-NEXT:    vmv.v.i v8, 0
+; CHECK-NEXT:    vs1r.v v8, (a1)
+; CHECK-NEXT:    addi a0, a0, 64
+; CHECK-NEXT:    vs1r.v v8, (a0)
+; CHECK-NEXT:    ret
+  %q = getelementptr inbounds i8, ptr %p, i64 84
+  %x = load i32, ptr %q
+  call void @llvm.memset.p0.i64(ptr %p, i8 0, i64 96, i1 false)
+  store i32 %x, ptr %q
+  ret void
+}