TheRock/compiler/amd-llvm/llvm/test/Transforms/InstSimplify/result-of-add-of-negative-is-non-zero-and-no-underflow.ll

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

; Here we add unsigned two values, check that addition did not underflow AND
; that the result is non-zero. This can be simplified just to a comparison
; between the base and negated offset.

declare void @use8(i8)

declare void @use1(i1)
declare void @llvm.assume(i1)

; If we are checking that the result is not null or no underflow happened,
; it is tautological (always-true).
define i1 @t1(i8 %base, i8 %offset) {
; CHECK-LABEL: @t1(
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT:    ret i1 true
;
  %cmp = icmp slt i8 %base, 0
  call void @llvm.assume(i1 %cmp)

  %adjusted = add i8 %base, %offset
  call void @use8(i8 %adjusted)
  %not_null = icmp ne i8 %adjusted, 0
  %no_underflow = icmp ult i8 %adjusted, %base
  %r = or i1 %not_null, %no_underflow
  ret i1 %r
}
define i1 @t2_commutative(i8 %base, i8 %offset) {
; CHECK-LABEL: @t2_commutative(
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT:    ret i1 true
;
  %cmp = icmp slt i8 %base, 0
  call void @llvm.assume(i1 %cmp)

  %adjusted = add i8 %base, %offset
  call void @use8(i8 %adjusted)
  %not_null = icmp ne i8 %adjusted, 0
  %no_underflow = icmp ugt i8 %base, %adjusted
  %r = or i1 %not_null, %no_underflow
  ret i1 %r
}

; If we are checking that the result is null and underflow happened,
; it is tautological (always-false).
define i1 @t3(i8 %base, i8 %offset) {
; CHECK-LABEL: @t3(
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT:    ret i1 false
;
  %cmp = icmp slt i8 %base, 0
  call void @llvm.assume(i1 %cmp)

  %adjusted = add i8 %base, %offset
  call void @use8(i8 %adjusted)
  %not_null = icmp eq i8 %adjusted, 0
  %no_underflow = icmp uge i8 %adjusted, %base
  %r = and i1 %not_null, %no_underflow
  ret i1 %r
}
define i1 @t4_commutative(i8 %base, i8 %offset) {
; CHECK-LABEL: @t4_commutative(
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT:    ret i1 false
;
  %cmp = icmp slt i8 %base, 0
  call void @llvm.assume(i1 %cmp)

  %adjusted = add i8 %base, %offset
  call void @use8(i8 %adjusted)
  %not_null = icmp eq i8 %adjusted, 0
  %no_underflow = icmp ule i8 %base, %adjusted
  %r = and i1 %not_null, %no_underflow
  ret i1 %r
}

; We only need to know that any of the 'add' operands is non-zero,
; not necessarily the one used in the comparison.
define i1 @t5(i8 %base, i8 %offset) {
; CHECK-LABEL: @t5(
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[OFFSET:%.*]], 0
; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET]]
; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
; CHECK-NEXT:    [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
; CHECK-NEXT:    ret i1 [[R]]
;
  %cmp = icmp slt i8 %offset, 0
  call void @llvm.assume(i1 %cmp)

  %adjusted = add i8 %base, %offset
  call void @use8(i8 %adjusted)
  %not_null = icmp ne i8 %adjusted, 0
  %no_underflow = icmp ult i8 %adjusted, %base
  %r = or i1 %not_null, %no_underflow
  ret i1 %r
}