llvm/llvm/test/Transforms/LoopVectorize/AArch64/reg-usage.ll

; REQUIRES: asserts

; RUN: opt -mtriple arm64-linux -passes=loop-vectorize -mattr=+sve -debug-only=loop-vectorize -disable-output <%s 2>&1 | FileCheck %s

; Invariant register usage calculation should take into account if the
; invariant would be used in widened instructions. Only in such cases, a vector
; register would be required for holding the invariant. For all other cases
; such as below(where usage of %0 in loop doesnt require vector register), a
; general purpose register suffices.
; Check that below test doesn't crash while calculating register usage for
; invariant %0

@string = internal unnamed_addr constant [5 x i8] c"abcd\00", align 1
define void @get_invariant_reg_usage(ptr %z) {
; CHECK: LV: Checking a loop in 'get_invariant_reg_usage'
; CHECK: LV(REG): VF = vscale x 16
; CHECK-NEXT: LV(REG): Found max usage: 1 item
; CHECK-NEXT: LV(REG): RegisterClass: Generic::ScalarRC, 3 registers
; CHECK-NEXT: LV(REG): Found invariant usage: 2 item
; CHECK-NEXT: LV(REG): RegisterClass: Generic::ScalarRC, 2 registers
; CHECK-NEXT: LV(REG): RegisterClass: Generic::VectorRC, 8 registers 

L.entry:
  %0 = load i128, ptr %z, align 16
  %1 = icmp slt i128 %0, 1
  %a = getelementptr i8, ptr %z, i64 1
  br i1 %1, label %return, label %loopbody

loopbody:                  ;preds = %L.entry, %loopbody
  %b = phi ptr [ %2, %loopbody ], [ @string, %L.entry ]
  %len_input = phi i128 [ %len, %loopbody ], [ %0, %L.entry ]
  %len = add nsw i128 %len_input, -1
  %2 = getelementptr i8, ptr %b, i64 1
  %3 = load i8, ptr %b, align 1
  store i8 %3, ptr %a, align 4
  %.not = icmp eq i128 %len, 0
  br i1 %.not, label %return, label %loopbody

return:                    ;preds = %loopexit, %L.entry
  ret void
}