[PowerPC] add a testcase for byval parameter; NFC

llvm/test/CodeGen/PowerPC/byval.ll

@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -verify-machineinstrs < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-n32:64-S128-v256:256:256-v512:512:512"
+target triple = "powerpc64le-unknown-linux-gnu"
+
+%struct = type { [4 x i32], [20 x i8] }
+
+declare dso_local i32 @foo1(%struct* byval(%struct) %var)
+declare dso_local void @foo(%struct* %var)
+
+; FIXME: for the byval parameter %x, now the memory for local variable and
+; for parameter save area are overlap.
+; For the below case,
+; the local variable space is r1 + 40 ~ r1 + 76
+; the parameter save area is r1 + 32 ~ r1 + 68
+
+define dso_local i32 @bar() {
+; CHECK-LABEL: bar:
+; CHECK:    addi 30, 1, 40
+; CHECK:    li 3, 16
+; CHECK:    lxvd2x 0, 30, 3
+; CHECK:    li 3, 48
+; CHECK:    stxvd2x 0, 1, 3
+; CHECK:    li 3, 32
+; CHECK:    lxvd2x 0, 0, 30
+; CHECK:    stxvd2x 0, 1, 3
+; CHECK:    lwz 3, 72(1)
+; CHECK:    stw 3, 64(1)
+entry:
+  %x = alloca %struct, align 4
+  call void @foo(%struct* %x)
+  %r = call i32 @foo1(%struct* byval(%struct) %x)
+  ret i32 %r
+}