llvm/test/Transforms/InstSimplify/icmp-equiv-zero.ll

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

; Test that comparisons with -1 and 1 are transformed to equivalent
; comparisons with 0, enabling simplifyICmpWithZero optimizations.

; ============================================================================
; Tests for icmp sgt X, -1 --> icmp sge X, 0
; ============================================================================

define i1 @sgt_minus1_nonnegative(i32 %x) {
; CHECK-LABEL: @sgt_minus1_nonnegative(
; CHECK-NEXT:    ret i1 true
;
  %nonneg = and i32 %x, 2147483647  ; Clear sign bit, making x non-negative
  %cmp = icmp sgt i32 %nonneg, -1
  ret i1 %cmp
}

define i1 @sgt_minus1_positive(i32 %x) {
; CHECK-LABEL: @sgt_minus1_positive(
; CHECK-NEXT:    ret i1 true
;
  %pos = or i32 %x, 1  ; Set bit 0
  %masked = and i32 %pos, 2147483647  ; Clear sign bit, making it non-negative and non-zero
  %cmp = icmp sgt i32 %masked, -1
  ret i1 %cmp
}

define i1 @sgt_minus1_negative(i32 %x) {
; CHECK-LABEL: @sgt_minus1_negative(
; CHECK-NEXT:    ret i1 false
;
  %neg = or i32 %x, -2147483648  ; Set sign bit, making x negative
  %cmp = icmp sgt i32 %neg, -1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp sle X, -1 --> icmp slt X, 0
; ============================================================================

define i1 @sle_minus1_nonnegative(i32 %x) {
; CHECK-LABEL: @sle_minus1_nonnegative(
; CHECK-NEXT:    ret i1 false
;
  %nonneg = and i32 %x, 2147483647  ; Clear sign bit
  %cmp = icmp sle i32 %nonneg, -1
  ret i1 %cmp
}

define i1 @sle_minus1_negative(i32 %x) {
; CHECK-LABEL: @sle_minus1_negative(
; CHECK-NEXT:    ret i1 true
;
  %neg = or i32 %x, -2147483648  ; Set sign bit
  %cmp = icmp sle i32 %neg, -1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp ugt X, -1 --> icmp ult X, 0
; ============================================================================
; Note: -1 in unsigned is the maximum value (all bits set), so ugt X, -1 is always false

define i1 @ugt_minus1_any(i32 %x) {
; CHECK-LABEL: @ugt_minus1_any(
; CHECK-NEXT:    ret i1 false
;
  %cmp = icmp ugt i32 %x, -1
  ret i1 %cmp
}

define i1 @ugt_minus1_zero(i32 %x) {
; CHECK-LABEL: @ugt_minus1_zero(
; CHECK-NEXT:    ret i1 false
;
  %zero = and i32 %x, 0  ; Make x = 0
  %cmp = icmp ugt i32 %zero, -1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp ule X, -1 --> icmp uge X, 0
; ============================================================================
; Note: -1 in unsigned is the maximum value, so ule X, -1 is always true

define i1 @ule_minus1_any(i32 %x) {
; CHECK-LABEL: @ule_minus1_any(
; CHECK-NEXT:    ret i1 true
;
  %cmp = icmp ule i32 %x, -1
  ret i1 %cmp
}

define i1 @ule_minus1_nonzero(i32 %x) {
; CHECK-LABEL: @ule_minus1_nonzero(
; CHECK-NEXT:    ret i1 true
;
  %nonzero = or i32 %x, 1  ; Make x non-zero
  %cmp = icmp ule i32 %nonzero, -1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp sge X, 1 --> icmp sgt X, 0
; ============================================================================

define i1 @sge_1_positive(i32 %x) {
; CHECK-LABEL: @sge_1_positive(
; CHECK-NEXT:    ret i1 true
;
  %pos = or i32 %x, 1  ; Set bit 0
  %masked = and i32 %pos, 2147483647  ; Clear sign bit, making it positive
  %cmp = icmp sge i32 %masked, 1
  ret i1 %cmp
}

define i1 @sge_1_zero(i32 %x) {
; CHECK-LABEL: @sge_1_zero(
; CHECK-NEXT:    ret i1 false
;
  %zero = and i32 %x, 0  ; Make x = 0
  %cmp = icmp sge i32 %zero, 1
  ret i1 %cmp
}

define i1 @sge_1_negative(i32 %x) {
; CHECK-LABEL: @sge_1_negative(
; CHECK-NEXT:    ret i1 false
;
  %neg = or i32 %x, -2147483648  ; Set sign bit
  %cmp = icmp sge i32 %neg, 1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp uge X, 1 --> icmp ugt X, 0
; ============================================================================

define i1 @uge_1_nonzero(i32 %x) {
; CHECK-LABEL: @uge_1_nonzero(
; CHECK-NEXT:    ret i1 true
;
  %nonzero = or i32 %x, 1  ; Make x non-zero (at least 1)
  %cmp = icmp uge i32 %nonzero, 1
  ret i1 %cmp
}

define i1 @uge_1_zero(i32 %x) {
; CHECK-LABEL: @uge_1_zero(
; CHECK-NEXT:    ret i1 false
;
  %zero = and i32 %x, 0  ; Make x = 0
  %cmp = icmp uge i32 %zero, 1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp slt X, 1 --> icmp sle X, 0
; ============================================================================

define i1 @slt_1_zero(i32 %x) {
; CHECK-LABEL: @slt_1_zero(
; CHECK-NEXT:    ret i1 true
;
  %zero = and i32 %x, 0  ; Make x = 0
  %cmp = icmp slt i32 %zero, 1
  ret i1 %cmp
}

define i1 @slt_1_negative(i32 %x) {
; CHECK-LABEL: @slt_1_negative(
; CHECK-NEXT:    ret i1 true
;
  %neg = or i32 %x, -2147483648  ; Set sign bit
  %cmp = icmp slt i32 %neg, 1
  ret i1 %cmp
}

define i1 @slt_1_positive(i32 %x) {
; CHECK-LABEL: @slt_1_positive(
; CHECK-NEXT:    ret i1 false
;
  %pos = or i32 %x, 1  ; Set bit 0
  %masked = and i32 %pos, 2147483647  ; Clear sign bit, making it positive
  %cmp = icmp slt i32 %masked, 1
  ret i1 %cmp
}

; ============================================================================
; Tests for icmp ult X, 1 --> icmp ule X, 0
; ============================================================================

define i1 @ult_1_zero(i32 %x) {
; CHECK-LABEL: @ult_1_zero(
; CHECK-NEXT:    ret i1 true
;
  %zero = and i32 %x, 0  ; Make x = 0
  %cmp = icmp ult i32 %zero, 1
  ret i1 %cmp
}

define i1 @ult_1_nonzero(i32 %x) {
; CHECK-LABEL: @ult_1_nonzero(
; CHECK-NEXT:    ret i1 false
;
  %nonzero = or i32 %x, 1  ; Make x non-zero (at least 1)
  %cmp = icmp ult i32 %nonzero, 1
  ret i1 %cmp
}