reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt %s -instcombine -S | FileCheck %s

; Fold
;   x - ((x / y) * y)
; to
;   x % y

; Also,
;   ((x / y) * y)
; can then be simplified to
;   x - (x % y)

declare void @use8(i8)
declare void @use2xi8(<2 x i8>)

define i8 @t0_basic(i8 %x, i8 %y) {
; CHECK-LABEL: @t0_basic(
; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[DIV]])
; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT:    ret i8 [[REM]]
;
  %div = sdiv i8 %x, %y
  call void @use8(i8 %div)
  %roundXdownToMultipleOfY = mul i8 %div, %y
  %rem = sub i8 %x, %roundXdownToMultipleOfY
  ret i8 %rem
}

define <2 x i8> @t1_vector(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @t1_vector(
; CHECK-NEXT:    [[DIV:%.*]] = sdiv <2 x i8> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT:    call void @use2xi8(<2 x i8> [[DIV]])
; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul <2 x i8> [[DIV]], [[Y]]
; CHECK-NEXT:    [[REM:%.*]] = sub <2 x i8> [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT:    ret <2 x i8> [[REM]]
;
  %div = sdiv <2 x i8> %x, %y
  call void @use2xi8(<2 x i8> %div)
  %roundXdownToMultipleOfY = mul <2 x i8> %div, %y
  %rem = sub <2 x i8> %x, %roundXdownToMultipleOfY
  ret <2 x i8> %rem
}

; Extra use

define i8 @t4_extrause(i8 %x, i8 %y) {
; CHECK-LABEL: @t4_extrause(
; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[DIV]])
; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
; CHECK-NEXT:    call void @use8(i8 [[ROUNDXDOWNTOMULTIPLEOFY]])
; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT:    ret i8 [[REM]]
;
  %div = sdiv i8 %x, %y
  call void @use8(i8 %div)
  %roundXdownToMultipleOfY = mul i8 %div, %y
  call void @use8(i8 %roundXdownToMultipleOfY)
  %rem = sub i8 %x, %roundXdownToMultipleOfY
  ret i8 %rem
}

; Commutativity

declare i8 @gen8()

define i8 @t5_commutative(i8 %x) {
; CHECK-LABEL: @t5_commutative(
; CHECK-NEXT:    [[Y:%.*]] = call i8 @gen8()
; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[X:%.*]], [[Y]]
; CHECK-NEXT:    call void @use8(i8 [[DIV]])
; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[Y]], [[DIV]]
; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT:    ret i8 [[REM]]
;
  %y = call i8 @gen8()
  %div = sdiv i8 %x, %y
  call void @use8(i8 %div)
  %roundXdownToMultipleOfY = mul i8 %y, %div ; swapped
  %rem = sub i8 %x, %roundXdownToMultipleOfY
  ret i8 %rem
}

; Negative tests

define i8 @n6_different_x(i8 %x0, i8 %x1, i8 %y) {
; CHECK-LABEL: @n6_different_x(
; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[X0:%.*]], [[Y:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[DIV]])
; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X1:%.*]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT:    ret i8 [[REM]]
;
  %div = sdiv i8 %x0, %y
  call void @use8(i8 %div)
  %roundXdownToMultipleOfY = mul i8 %div, %y
  %rem = sub i8 %x1, %roundXdownToMultipleOfY
  ret i8 %rem
}

define i8 @n6_different_y(i8 %x, i8 %y0, i8 %y1) {
; CHECK-LABEL: @n6_different_y(
; CHECK-NEXT:    [[DIV:%.*]] = sdiv i8 [[X:%.*]], [[Y0:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[DIV]])
; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y1:%.*]]
; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
; CHECK-NEXT:    ret i8 [[REM]]
;
  %div = sdiv i8 %x, %y0
  call void @use8(i8 %div)
  %roundXdownToMultipleOfY = mul i8 %div, %y1
  %rem = sub i8 %x, %roundXdownToMultipleOfY
  ret i8 %rem
}