llvm-project/llvm/test/Transforms/InstCombine/known-phi-br.ll

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

;
; Tests to show cases where computeKnownBits should be able to determine
; the known bits of a phi edge based off a conditional branch feeding the phi.
;

; %x either eq 7 or is set to 7
define i64 @limit_i64_eq_7(i64 %x) {
; CHECK-LABEL: @limit_i64_eq_7(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i64 [[X:%.*]], 7
; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    ret i64 7
;
entry:
  %cmp = icmp eq i64 %x, 7
  br i1 %cmp, label %end, label %body
body:
  br label %end
end:
  %res = phi i64 [ %x, %entry ], [ 7, %body ]
  ret i64 %res
}

; %x either eq 255 or is set to 255
define i64 @limit_i64_ne_255(i64 %x) {
; CHECK-LABEL: @limit_i64_ne_255(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[X:%.*]], 255
; CHECK-NEXT:    call void @use(i1 [[CMP]])
; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
; CHECK:       body:
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    ret i64 255
;
entry:
  %cmp = icmp ne i64 %x, 255
  call void @use(i1 %cmp)
  br i1 %cmp, label %body, label %end
body:
  br label %end
end:
  %res = phi i64 [ %x, %entry ], [ 255, %body ]
  ret i64 %res
}
declare void @use(i1)

; %x either ule 15 or is masked with 15
define i64 @limit_i64_ule_15(i64 %x) {
; CHECK-LABEL: @limit_i64_ule_15(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 16
; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 15
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
; CHECK-NEXT:    ret i64 [[X_MASK]]
;
entry:
  %cmp = icmp ule i64 %x, 15
  br i1 %cmp, label %end, label %body
body:
  %mask = and i64 %x, 15
  br label %end
end:
  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
  %res = and i64 %x.mask, 15
  ret i64 %res
}

; %x either uge 8 or is masked with 7
define i64 @limit_i64_uge_8(i64 %x) {
; CHECK-LABEL: @limit_i64_uge_8(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i64 [[X:%.*]], 7
; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
; CHECK-NEXT:    ret i64 [[X_MASK]]
;
entry:
  %cmp = icmp uge i64 %x, 8
  br i1 %cmp, label %body, label %end
body:
  %mask = and i64 %x, 7
  br label %end
end:
  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
  %res = and i64 %x.mask, 7
  ret i64 %res
}

; %x either ult 8 or is masked with 7
define i64 @limit_i64_ult_8(i64 %x) {
; CHECK-LABEL: @limit_i64_ult_8(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 8
; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
; CHECK-NEXT:    ret i64 [[X_MASK]]
;
entry:
  %cmp = icmp ult i64 %x, 8
  br i1 %cmp, label %end, label %body
body:
  %mask = and i64 %x, 7
  br label %end
end:
  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
  %res = and i64 %x.mask, 7
  ret i64 %res
}

; %x either ugt 7 or is masked with 7
define i64 @limit_i64_ugt_7(i64 %x) {
; CHECK-LABEL: @limit_i64_ugt_7(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i64 [[X:%.*]], 7
; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
; CHECK-NEXT:    ret i64 [[X_MASK]]
;
entry:
  %cmp = icmp ugt i64 %x, 7
  br i1 %cmp, label %body, label %end
body:
  %mask = and i64 %x, 7
  br label %end
end:
  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
  %res = and i64 %x.mask, 7
  ret i64 %res
}

;
; negative tests
;

; %x either ule 15 or is masked with 15
define i64 @limit_i64_ule_15_mask3(i64 %x) {
; CHECK-LABEL: @limit_i64_ule_15_mask3(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 16
; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 15
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 3
; CHECK-NEXT:    ret i64 [[RES]]
;
entry:
  %cmp = icmp ule i64 %x, 15
  br i1 %cmp, label %end, label %body
body:
  %mask = and i64 %x, 15
  br label %end
end:
  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
  %res = and i64 %x.mask, 3
  ret i64 %res
}

; %x either ult 8 or is masked with 7
define i64 @limit_i64_ult_8_mask1(i64 %x) {
; CHECK-LABEL: @limit_i64_ult_8_mask1(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 8
; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
; CHECK:       body:
; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
; CHECK-NEXT:    br label [[END]]
; CHECK:       end:
; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 1
; CHECK-NEXT:    ret i64 [[RES]]
;
entry:
  %cmp = icmp ult i64 %x, 8
  br i1 %cmp, label %end, label %body
body:
  %mask = and i64 %x, 7
  br label %end
end:
  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
  %res = and i64 %x.mask, 1
  ret i64 %res
}