llvm/test/Transforms/SLPVectorizer/test_intermediate_dual_use.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; TEST 3: Intermediate Node Dual Use
; Construct a chain where an intermediate value becomes poison,
; and is then used in a safe way and an unsafe way.

; RUN: opt -S --passes=slp-vectorizer < %s | FileCheck %s

define i1 @test_intermediate_dual_use(<4 x i32> %x) {
; CHECK-LABEL: define i1 @test_intermediate_dual_use(
; CHECK-SAME: <4 x i32> [[X:%.*]]) {
; CHECK-NEXT:    [[X0:%.*]] = extractelement <4 x i32> [[X]], i32 0
; CHECK-NEXT:    [[P_VAL:%.*]] = extractelement <4 x i32> [[X]], i32 -1
; CHECK-NEXT:    [[LEAF_P:%.*]] = icmp eq i32 [[P_VAL]], 0
; CHECK-NEXT:    [[LEAF_F:%.*]] = icmp ugt i32 [[X0]], -1
; CHECK-NEXT:    [[OP_RDX2:%.*]] = select i1 true, i1 [[LEAF_F]], i1 false
; CHECK-NEXT:    [[OP_RDX3:%.*]] = select i1 [[OP_RDX2]], i1 [[LEAF_P]], i1 false
; CHECK-NEXT:    ret i1 [[OP_RDX3]]
;
  %x0 = extractelement <4 x i32> %x, i32 0

  ; Leaves
  %p_val = extractelement <4 x i32> %x, i32 -1
  %leaf_p = icmp eq i32 %p_val, 0 ; Poison
  %leaf_f = icmp ugt i32 %x0, -1 ; False

  ; Intermediate 1: Poison
  ; select poison, true, false -> poison
  %i1 = select i1 %leaf_p, i1 true, i1 false

  ; Intermediate 2: Safe usage of %i1
  ; select false, %i1, false -> false
  %safe = select i1 %leaf_f, i1 %i1, i1 false

  ; Intermediate 3: Unsafe usage of %i1 (as Condition)
  ; select %i1, true, false -> poison
  %unsafe = select i1 %i1, i1 true, i1 false

  ; Final: safe && unsafe -> false && poison -> false
  %res = select i1 %safe, i1 %unsafe, i1 false

  ret i1 %res
}