xref: /llvm-project/llvm/test/Analysis/ValueTracking/numsignbits-shl.ll (revision 38fffa630ee80163dc65e759392ad29798905679)

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes=instcombine -S < %s | FileCheck %s

declare void @escape(i16 %add)
declare void @escape2(<2 x i16> %add)

define void @numsignbits_shl_zext(i8 %x) {
; CHECK-LABEL: define void @numsignbits_shl_zext(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT:    [[ASHR:%.*]] = ashr i8 [[X]], 5
; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[ASHR]] to i16
; CHECK-NEXT:    [[NSB4:%.*]] = shl i16 [[ZEXT]], 10
; CHECK-NEXT:    [[ADD14:%.*]] = and i16 [[NSB4]], 15360
; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
; CHECK-NEXT:    [[ADD13:%.*]] = and i16 [[NSB4]], 7168
; CHECK-NEXT:    call void @escape(i16 [[ADD13]])
; CHECK-NEXT:    [[ADD12:%.*]] = and i16 [[NSB4]], 3072
; CHECK-NEXT:    call void @escape(i16 [[ADD12]])
; CHECK-NEXT:    [[AND11:%.*]] = and i16 [[NSB4]], 2048
; CHECK-NEXT:    [[ADD11:%.*]] = add nsw i16 [[AND11]], [[NSB4]]
; CHECK-NEXT:    call void @escape(i16 [[ADD11]])
; CHECK-NEXT:    ret void
;
  %ashr = ashr i8 %x, 5
  %zext = zext i8 %ashr to i16
  %nsb4 = shl i16 %zext, 10
  ; Validate ComputeNumSignBits using this simplification:
  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
  ; 4 sign bits: Goal is to fold away the add for bits 12-14.
  %and14 = and i16 %nsb4, 16384
  %add14 = add i16 %and14, %nsb4
  call void @escape(i16 %add14)
  %and13 = and i16 %nsb4, 8192
  %add13 = add i16 %and13, %nsb4
  call void @escape(i16 %add13)
  %and12 = and i16 %nsb4, 4096
  %add12 = add i16 %and12, %nsb4
  call void @escape(i16 %add12)
  %and11 = and i16 %nsb4, 2048
  %add11 = add i16 %and11, %nsb4
  call void @escape(i16 %add11)
  ret void
}

define void @numsignbits_shl_zext_shift_amounr_matches_extend(i8 %x) {
; CHECK-LABEL: define void @numsignbits_shl_zext_shift_amounr_matches_extend(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT:    [[ASHR:%.*]] = ashr i8 [[X]], 2
; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[ASHR]] to i16
; CHECK-NEXT:    [[NSB3:%.*]] = shl nuw i16 [[ZEXT]], 8
; CHECK-NEXT:    [[ADD14:%.*]] = and i16 [[NSB3]], 16128
; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
; CHECK-NEXT:    [[ADD13:%.*]] = and i16 [[NSB3]], 7936
; CHECK-NEXT:    call void @escape(i16 [[ADD13]])
; CHECK-NEXT:    [[AND12:%.*]] = and i16 [[NSB3]], 4096
; CHECK-NEXT:    [[ADD12:%.*]] = add nsw i16 [[AND12]], [[NSB3]]
; CHECK-NEXT:    call void @escape(i16 [[ADD12]])
; CHECK-NEXT:    ret void
;
  %ashr = ashr i8 %x, 2
  %zext = zext i8 %ashr to i16
  %nsb3 = shl i16 %zext, 8
  ; Validate ComputeNumSignBits using this simplification:
  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
  ; 3 sign bits: Goal is to fold away the add for bits 13-14.
  %and14 = and i16 %nsb3, 16384
  %add14 = add i16 %and14, %nsb3
  call void @escape(i16 %add14)
  %and13 = and i16 %nsb3, 8192
  %add13 = add i16 %and13, %nsb3
  call void @escape(i16 %add13)
  %and12 = and i16 %nsb3, 4096
  %add12 = add i16 %and12, %nsb3
  call void @escape(i16 %add12)
  ret void
}

define void @numsignbits_shl_zext_extended_bits_remains(i8 %x) {
; CHECK-LABEL: define void @numsignbits_shl_zext_extended_bits_remains(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT:    [[ASHR:%.*]] = ashr i8 [[X]], 5
; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[ASHR]] to i16
; CHECK-NEXT:    [[NSB1:%.*]] = shl nuw nsw i16 [[ZEXT]], 7
; CHECK-NEXT:    [[AND14:%.*]] = and i16 [[NSB1]], 16384
; CHECK-NEXT:    [[ADD14:%.*]] = add nuw i16 [[AND14]], [[NSB1]]
; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
; CHECK-NEXT:    ret void
;
  %ashr = ashr i8 %x, 5
  %zext = zext i8 %ashr to i16
  %nsb1 = shl i16 %zext, 7
  ; Validate ComputeNumSignBits using this simplification:
  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
  ; 1 sign bit: The add can't be folded away here.
  %and14 = and i16 %nsb1, 16384
  %add14 = add i16 %and14, %nsb1
  call void @escape(i16 %add14)
  ret void
}

define void @numsignbits_shl_zext_all_bits_shifted_out(i8 %x) {
; CHECK-LABEL: define void @numsignbits_shl_zext_all_bits_shifted_out(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT:    [[ASHR:%.*]] = lshr i8 [[X]], 5
; CHECK-NEXT:    [[ZEXT:%.*]] = zext nneg i8 [[ASHR]] to i16
; CHECK-NEXT:    [[NSB1:%.*]] = shl i16 [[ZEXT]], 14
; CHECK-NEXT:    [[AND14:%.*]] = and i16 [[NSB1]], 16384
; CHECK-NEXT:    [[ADD14:%.*]] = add i16 [[AND14]], [[NSB1]]
; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
; CHECK-NEXT:    ret void
;
  %ashr = ashr i8 %x, 5
  %zext = zext i8 %ashr to i16
  %nsb1 = shl i16 %zext, 14
  ; Validate ComputeNumSignBits using this simplification:
  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
  ; 1 sign bit: The add can't be folded away here.
  %and14 = and i16 %nsb1, 16384
  %add14 = add i16 %and14, %nsb1
  call void @escape(i16 %add14)
  ret void
}

define void @numsignbits_shl_zext_vector(<2 x i8> %x) {
; CHECK-LABEL: define void @numsignbits_shl_zext_vector(
; CHECK-SAME: <2 x i8> [[X:%.*]]) {
; CHECK-NEXT:    [[ASHR:%.*]] = ashr <2 x i8> [[X]], splat (i8 5)
; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[ASHR]] to <2 x i16>
; CHECK-NEXT:    [[NSB4:%.*]] = shl <2 x i16> [[ZEXT]], splat (i16 10)
; CHECK-NEXT:    [[ADD14:%.*]] = and <2 x i16> [[NSB4]], splat (i16 15360)
; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD14]])
; CHECK-NEXT:    [[ADD13:%.*]] = and <2 x i16> [[NSB4]], splat (i16 7168)
; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD13]])
; CHECK-NEXT:    [[ADD12:%.*]] = and <2 x i16> [[NSB4]], splat (i16 3072)
; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD12]])
; CHECK-NEXT:    [[AND11:%.*]] = and <2 x i16> [[NSB4]], splat (i16 2048)
; CHECK-NEXT:    [[ADD11:%.*]] = add nsw <2 x i16> [[AND11]], [[NSB4]]
; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD11]])
; CHECK-NEXT:    ret void
;
  %ashr = ashr <2 x i8> %x, <i8 5, i8 5>
  %zext = zext <2 x i8> %ashr to <2 x i16>
  %nsb4 = shl <2 x i16> %zext, <i16 10, i16 10>
  ; Validate ComputeNumSignBits using this simplification:
  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
  ; 4 sign bits: Goal is to fold away the add for bits 12-14.
  %and14 = and <2 x i16> %nsb4, <i16 16384, i16 16384>
  %add14 = add <2 x i16> %and14, %nsb4
  call void @escape2(<2 x i16> %add14)
  %and13 = and <2 x i16> %nsb4, <i16 8192, i16 8192>
  %add13 = add <2 x i16> %and13, %nsb4
  call void @escape2(<2 x i16> %add13)
  %and12 = and <2 x i16> %nsb4, <i16 4096, i16 4096>
  %add12 = add <2 x i16> %and12, %nsb4
  call void @escape2(<2 x i16> %add12)
  %and11 = and <2 x i16> %nsb4, <i16 2048, i16 2048>
  %add11 = add <2 x i16> %and11, %nsb4
  call void @escape2(<2 x i16> %add11)
  ret void
}