test/Transforms/Reassociate/2002-05-15-SubReassociate.ll

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

; With sub reassociation, constant folding can eliminate all of the constants.
define i32 @test1(i32 %A, i32 %B) {
; CHECK-LABEL: @test1(
; CHECK-NEXT:    [[Z:%.*]] = sub i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT:    ret i32 [[Z]]
;
  %W = add i32 5, %B
  %X = add i32 -7, %A
  %Y = sub i32 %X, %W
  %Z = add i32 %Y, 12
  ret i32 %Z
}

; With sub reassociation, constant folding can eliminate the two 12 constants.
define i32 @test2(i32 %A, i32 %B, i32 %C, i32 %D) {
; CHECK-LABEL: @test2(
; CHECK-NEXT:    [[TMP1:%.*]] = add i32 [[B:%.*]], [[A:%.*]]
; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[TMP1]], [[C:%.*]]
; CHECK-NEXT:    [[Q:%.*]] = sub i32 [[D:%.*]], [[TMP2]]
; CHECK-NEXT:    ret i32 [[Q]]
;
  %M = add i32 %A, 12
  %N = add i32 %M, %B
  %O = add i32 %N, %C
  %P = sub i32 %D, %O
  %Q = add i32 %P, 12
  ret i32 %Q
}