llvm-project/llvm/test/Analysis/ValueTracking/knownzero-shift.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -instsimplify -S < %s | FileCheck %s

define i1 @test(i8 %p, i8* %pq) {
; CHECK-LABEL: @test(
; CHECK-NEXT:    ret i1 false
;
  %q = load i8, i8* %pq, !range !0 ; %q is known nonzero; no known bits
  %1 = or i8 %p, 2                 ; %1[1] = 1
  %2 = and i8 %1, 254              ; %2[0] = 0, %2[1] = 1
  %A = lshr i8 %2, 1               ; We should know that %A is nonzero.
  %x = icmp eq i8 %A, 0
  ret i1 %x
}

!0 = !{ i8 1, i8 5 }

; The following cases only get folded by InstCombine,
; see InstCombine/shift-shift.ll. If we wanted to,
; we could explicitly handle them in InstSimplify as well.

define i32 @shl_shl(i32 %A) {
; CHECK-LABEL: @shl_shl(
; CHECK-NEXT:    [[B:%.*]] = shl i32 [[A:%.*]], 6
; CHECK-NEXT:    [[C:%.*]] = shl i32 [[B]], 28
; CHECK-NEXT:    ret i32 [[C]]
;
  %B = shl i32 %A, 6
  %C = shl i32 %B, 28
  ret i32 %C
}

define <2 x i33> @shl_shl_splat_vec(<2 x i33> %A) {
; CHECK-LABEL: @shl_shl_splat_vec(
; CHECK-NEXT:    [[B:%.*]] = shl <2 x i33> [[A:%.*]], <i33 5, i33 5>
; CHECK-NEXT:    [[C:%.*]] = shl <2 x i33> [[B]], <i33 28, i33 28>
; CHECK-NEXT:    ret <2 x i33> [[C]]
;
  %B = shl <2 x i33> %A, <i33 5, i33 5>
  %C = shl <2 x i33> %B, <i33 28, i33 28>
  ret <2 x i33> %C
}

; FIXME

define <2 x i33> @shl_shl_vec(<2 x i33> %A) {
; CHECK-LABEL: @shl_shl_vec(
; CHECK-NEXT:    [[B:%.*]] = shl <2 x i33> [[A:%.*]], <i33 6, i33 5>
; CHECK-NEXT:    [[C:%.*]] = shl <2 x i33> [[B]], <i33 27, i33 28>
; CHECK-NEXT:    ret <2 x i33> [[C]]
;
  %B = shl <2 x i33> %A, <i33 6, i33 5>
  %C = shl <2 x i33> %B, <i33 27, i33 28>
  ret <2 x i33> %C
}

define i232 @lshr_lshr(i232 %A) {
; CHECK-LABEL: @lshr_lshr(
; CHECK-NEXT:    [[B:%.*]] = lshr i232 [[A:%.*]], 231
; CHECK-NEXT:    [[C:%.*]] = lshr i232 [[B]], 1
; CHECK-NEXT:    ret i232 [[C]]
;
  %B = lshr i232 %A, 231
  %C = lshr i232 %B, 1
  ret i232 %C
}

define <2 x i32> @lshr_lshr_splat_vec(<2 x i32> %A) {
; CHECK-LABEL: @lshr_lshr_splat_vec(
; CHECK-NEXT:    [[B:%.*]] = lshr <2 x i32> [[A:%.*]], <i32 28, i32 28>
; CHECK-NEXT:    [[C:%.*]] = lshr <2 x i32> [[B]], <i32 4, i32 4>
; CHECK-NEXT:    ret <2 x i32> [[C]]
;
  %B = lshr <2 x i32> %A, <i32 28, i32 28>
  %C = lshr <2 x i32> %B, <i32 4, i32 4>
  ret <2 x i32> %C
}

define <2 x i32> @lshr_lshr_vec(<2 x i32> %A) {
; CHECK-LABEL: @lshr_lshr_vec(
; CHECK-NEXT:    [[B:%.*]] = lshr <2 x i32> [[A:%.*]], <i32 29, i32 28>
; CHECK-NEXT:    [[C:%.*]] = lshr <2 x i32> [[B]], <i32 4, i32 5>
; CHECK-NEXT:    ret <2 x i32> [[C]]
;
  %B = lshr <2 x i32> %A, <i32 29, i32 28>
  %C = lshr <2 x i32> %B, <i32 4, i32 5>
  ret <2 x i32> %C
}