[ARM] Add test demonstrating parameter overwrite during copy

Author: dtellenbach

llvm/test/CodeGen/ARM/byval_struct_copy_tailcall.ll

@@ -0,0 +1,69 @@
+; RUN: llc -mtriple thumbv7em-apple-darwin -o - < %s | FileCheck %s
+
+%"struct.s1" = type { [19 x i32] }
+
+define void @f0(ptr byval(%"struct.s1") %0, ptr %1) #1 {
+; CHECK-LABEL: _f0:                                    @ @f0
+; CHECK-NEXT:  @ %bb.0:
+; CHECK-NEXT:  	sub	sp, #16
+; CHECK-NEXT:  	push	{r4, lr}
+; CHECK-NEXT:  	sub	sp, #76
+; CHECK-NEXT:  	add.w	r9, sp, #84
+; CHECK-NEXT:  	stm.w	r9, {r0, r1, r2, r3}
+; CHECK-NEXT:  	mov	r0, sp
+; CHECK-NEXT:  	add	r1, sp, #84
+; CHECK-NEXT:  	movs	r2, #76
+; CHECK-NEXT:  	mov	r3, r0
+; CHECK-NEXT:  LBB0_1:                                 @ =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:  	ldr	r4, [r1], #4
+; CHECK-NEXT:  	subs	r2, #4
+; CHECK-NEXT:  	str	r4, [r3], #4
+; CHECK-NEXT:  	bne	LBB0_1
+; CHECK-NEXT:  @ %bb.2:
+; CHECK-NEXT:  	add.w	r1, r0, #12
+; CHECK-NEXT:  	add	r0, sp, #100
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldr	r2, [r1], #4
+; CHECK-NEXT:  	str	r2, [r0], #4
+; CHECK-NEXT:  	ldm.w	sp, {r1, r2, r3}
+; CHECK-NEXT:  	ldr	r0, [sp, #160]
+; CHECK-NEXT:  	add	sp, #76
+; CHECK-NEXT:  	pop.w	{r4, lr}
+; CHECK-NEXT:  	add	sp, #16
+; CHECK-NEXT:  	b.w	_f1
+  tail call  void @f1(ptr %1, ptr byval(%"struct.s1") %0)
+  ret void
+}
+
+declare void @f1(ptr, ptr)
+
+attributes #1 = { nounwind "frame-pointes"="non-leaf" }