llvm-project/llvm/test/Transforms/InstCombine/icmp-div-constant.ll

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

target datalayout = "n32"

define i1 @is_rem2_neg_i8(i8 %x) {
; CHECK-LABEL: @is_rem2_neg_i8(
; CHECK-NEXT:    [[TMP1:%.*]] = and i8 [[X:%.*]], -127
; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[TMP1]], -127
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i8 %x, 2
  %r = icmp slt i8 %s, 0
  ret i1 %r
}

define <2 x i1> @is_rem2_pos_v2i8(<2 x i8> %x) {
; CHECK-LABEL: @is_rem2_pos_v2i8(
; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i8> [[X:%.*]], <i8 -127, i8 -127>
; CHECK-NEXT:    [[R:%.*]] = icmp eq <2 x i8> [[TMP1]], <i8 1, i8 1>
; CHECK-NEXT:    ret <2 x i1> [[R]]
;
  %s = srem <2 x i8> %x, <i8 2, i8 2>
  %r = icmp sgt <2 x i8> %s, zeroinitializer
  ret <2 x i1> %r
}

; i8 -97 == 159 == 0b10011111

define i1 @is_rem32_pos_i8(i8 %x) {
; CHECK-LABEL: @is_rem32_pos_i8(
; CHECK-NEXT:    [[TMP1:%.*]] = and i8 [[X:%.*]], -97
; CHECK-NEXT:    [[R:%.*]] = icmp sgt i8 [[TMP1]], 0
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i8 %x, 32
  %r = icmp sgt i8 %s, 0
  ret i1 %r
}

; i16 -32765 == 32771 == 0b1000000000000011

define i1 @is_rem4_neg_i16(i16 %x) {
; CHECK-LABEL: @is_rem4_neg_i16(
; CHECK-NEXT:    [[TMP1:%.*]] = and i16 [[X:%.*]], -32765
; CHECK-NEXT:    [[R:%.*]] = icmp ugt i16 [[TMP1]], -32768
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i16 %x, 4
  %r = icmp slt i16 %s, 0
  ret i1 %r
}

declare void @use(i32)

; TODO: This is still worth folding because srem is difficult?

define i1 @is_rem32_neg_i32_extra_use(i32 %x) {
; CHECK-LABEL: @is_rem32_neg_i32_extra_use(
; CHECK-NEXT:    [[S:%.*]] = srem i32 [[X:%.*]], 32
; CHECK-NEXT:    call void @use(i32 [[S]])
; CHECK-NEXT:    [[R:%.*]] = icmp slt i32 [[S]], 0
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i32 %x, 32
  call void @use(i32 %s)
  %r = icmp slt i32 %s, 0
  ret i1 %r
}

; Negative test - wrong compare constant

define i1 @is_rem8_nonneg_i16(i16 %x) {
; CHECK-LABEL: @is_rem8_nonneg_i16(
; CHECK-NEXT:    [[S:%.*]] = srem i16 [[X:%.*]], 8
; CHECK-NEXT:    [[R:%.*]] = icmp sgt i16 [[S]], -1
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i16 %x, 8
  %r = icmp sgt i16 %s, -1
  ret i1 %r
}

; Negative test - wrong remainder constant

define i1 @is_rem3_neg_i8(i8 %x) {
; CHECK-LABEL: @is_rem3_neg_i8(
; CHECK-NEXT:    [[S:%.*]] = srem i8 [[X:%.*]], 3
; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[S]], 0
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i8 %x, 3
  %r = icmp slt i8 %s, 0
  ret i1 %r
}

; Negative test - wrong compare constant

define i1 @is_rem16_something_i8(i8 %x) {
; CHECK-LABEL: @is_rem16_something_i8(
; CHECK-NEXT:    [[S:%.*]] = srem i8 [[X:%.*]], 16
; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[S]], 7
; CHECK-NEXT:    ret i1 [[R]]
;
  %s = srem i8 %x, 16
  %r = icmp slt i8 %s, 7
  ret i1 %r
}

; PR30281 - https://llvm.org/bugs/show_bug.cgi?id=30281

; All of these tests contain foldable division-by-constant instructions, but we
; can't assert that those folds have occurred before we process the later icmp.

define i32 @icmp_div(i16 %a, i16 %c) {
; CHECK-LABEL: @icmp_div(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i16 [[A:%.*]], 0
; CHECK-NEXT:    br i1 [[TOBOOL]], label [[THEN:%.*]], label [[EXIT:%.*]]
; CHECK:       then:
; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i16 [[C:%.*]], 0
; CHECK-NEXT:    [[PHI_BO:%.*]] = sext i1 [[CMP]] to i32
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       exit:
; CHECK-NEXT:    [[PHI:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[PHI_BO]], [[THEN]] ]
; CHECK-NEXT:    ret i32 [[PHI]]
;
entry:
  %tobool = icmp eq i16 %a, 0
  br i1 %tobool, label %then, label %exit

then:
  %div = sdiv i16 %c, -1
  %cmp = icmp ne i16 %div, 0
  br label %exit

exit:
  %phi = phi i1 [ false, %entry ], [ %cmp, %then ]
  %zext = zext i1 %phi to i32
  %add = add nsw i32 %zext, -1
  ret i32 %add
}

define i32 @icmp_div2(i16 %a, i16 %c) {
; CHECK-LABEL: @icmp_div2(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i16 [[A:%.*]], 0
; CHECK-NEXT:    br i1 [[TOBOOL]], label [[THEN:%.*]], label [[EXIT:%.*]]
; CHECK:       then:
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       exit:
; CHECK-NEXT:    ret i32 -1
;
entry:
  %tobool = icmp eq i16 %a, 0
  br i1 %tobool, label %then, label %exit

then:
  %div = sdiv i16 %c, 0
  %cmp = icmp ne i16 %div, 0
  br label %exit

exit:
  %phi = phi i1 [ false, %entry ], [ %cmp, %then ]
  %zext = zext i1 %phi to i32
  %add = add nsw i32 %zext, -1
  ret i32 %add
}

define i32 @icmp_div3(i16 %a, i16 %c) {
; CHECK-LABEL: @icmp_div3(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i16 [[A:%.*]], 0
; CHECK-NEXT:    br i1 [[TOBOOL]], label [[THEN:%.*]], label [[EXIT:%.*]]
; CHECK:       then:
; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i16 [[C:%.*]], 0
; CHECK-NEXT:    [[PHI_BO:%.*]] = sext i1 [[CMP]] to i32
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       exit:
; CHECK-NEXT:    [[PHI:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[PHI_BO]], [[THEN]] ]
; CHECK-NEXT:    ret i32 [[PHI]]
;
entry:
  %tobool = icmp eq i16 %a, 0
  br i1 %tobool, label %then, label %exit

then:
  %div = sdiv i16 %c, 1
  %cmp = icmp ne i16 %div, 0
  br label %exit

exit:
  %phi = phi i1 [ false, %entry ], [ %cmp, %then ]
  %zext = zext i1 %phi to i32
  %add = add nsw i32 %zext, -1
  ret i32 %add
}