llvm/test/Transforms/InstSimplify/phi.ll

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

; PR12189
define i1 @test1(i32 %x) {
; CHECK-LABEL: @test1(
; CHECK-NEXT:    br i1 true, label [[A:%.*]], label [[B:%.*]]
; CHECK:       a:
; CHECK-NEXT:    [[AA:%.*]] = or i32 [[X:%.*]], 10
; CHECK-NEXT:    br label [[C:%.*]]
; CHECK:       b:
; CHECK-NEXT:    [[BB:%.*]] = or i32 [[X]], 10
; CHECK-NEXT:    br label [[C]]
; CHECK:       c:
; CHECK-NEXT:    [[CC:%.*]] = phi i32 [ [[BB]], [[B]] ], [ [[AA]], [[A]] ]
; CHECK-NEXT:    [[D:%.*]] = urem i32 [[CC]], 2
; CHECK-NEXT:    [[E:%.*]] = icmp eq i32 [[D]], 0
; CHECK-NEXT:    ret i1 [[E]]
;
  br i1 true, label %a, label %b

a:
  %aa = or i32 %x, 10
  br label %c

b:
  %bb = or i32 %x, 10
  br label %c

c:
  %cc = phi i32 [ %bb, %b ], [%aa, %a ]
  %d = urem i32 %cc, 2
  %e = icmp eq i32 %d, 0
  ret i1 %e
}

; D63489 - https://reviews.llvm.org/D63489
; If this single-value phi form needs to be preserved to enable
; further analysis, then -passes=instsimplify should not be running?

define i32 @lcssa-phi(i32 %x) {
; CHECK-LABEL: @lcssa-phi(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[END:%.*]]
; CHECK:       end:
; CHECK-NEXT:    ret i32 [[X:%.*]]
;
entry:
  br label %end

end:
  %counter.lcssa = phi i32 [ %x, %entry ]
  ret i32 %counter.lcssa
}

define i32 @poison(i1 %cond, i32 %v) {
; CHECK-LABEL: @poison(
; CHECK-NEXT:    br i1 [[COND:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK:       A:
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       B:
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       EXIT:
; CHECK-NEXT:    ret i32 [[V:%.*]]
;
  br i1 %cond, label %A, label %B
A:
  br label %EXIT
B:
  br label %EXIT
EXIT:
  %w = phi i32 [%v, %A], [poison, %B]
  ret i32 %w
}

define i32 @undef(i1 %cond, i32 %v) {
; CHECK-LABEL: @undef(
; CHECK-NEXT:    br i1 [[COND:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK:       A:
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       B:
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       EXIT:
; CHECK-NEXT:    [[W:%.*]] = phi i32 [ [[V:%.*]], [[A]] ], [ undef, [[B]] ]
; CHECK-NEXT:    ret i32 [[W]]
;
  br i1 %cond, label %A, label %B
A:
  br label %EXIT
B:
  br label %EXIT
EXIT:
  %w = phi i32 [%v, %A], [undef, %B]
  ret i32 %w
}

define i8 @undef_poison(i1 %cond) {
; CHECK-LABEL: @undef_poison(
; CHECK-NEXT:    br i1 [[COND:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK:       A:
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       B:
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       EXIT:
; CHECK-NEXT:    ret i8 undef
;
  br i1 %cond, label %A, label %B
A:
  br label %EXIT
B:
  br label %EXIT
EXIT:
  %r = phi i8 [undef, %A], [poison, %B]
  ret i8 %r
}

define i8 @only_undef(i1 %cond) {
; CHECK-LABEL: @only_undef(
; CHECK-NEXT:    br i1 [[COND:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK:       A:
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       B:
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       EXIT:
; CHECK-NEXT:    ret i8 undef
;
  br i1 %cond, label %A, label %B
A:
  br label %EXIT
B:
  br label %EXIT
EXIT:
  %r = phi i8 [undef, %A], [undef, %B]
  ret i8 %r
}

define i8 @only_poison(i1 %cond) {
; CHECK-LABEL: @only_poison(
; CHECK-NEXT:    br i1 [[COND:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK:       A:
; CHECK-NEXT:    br label [[EXIT:%.*]]
; CHECK:       B:
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       EXIT:
; CHECK-NEXT:    ret i8 poison
;
  br i1 %cond, label %A, label %B
A:
  br label %EXIT
B:
  br label %EXIT
EXIT:
  %r = phi i8 [poison, %A], [poison, %B]
  ret i8 %r
}

; Should not fold srem to -1 due to incorrect context instruction when
; threading over phi.
define i32 @pr61312() {
; CHECK-LABEL: @pr61312(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[FOR_COND:%.*]]
; CHECK:       for.cond:
; CHECK-NEXT:    [[A_0:%.*]] = phi i32 [ 2, [[ENTRY:%.*]] ], [ [[DEC:%.*]], [[FOR_INC:%.*]] ]
; CHECK-NEXT:    [[CMP:%.*]] = icmp sge i32 [[A_0]], 0
; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_INC]], label [[FOR_END:%.*]]
; CHECK:       for.inc:
; CHECK-NEXT:    [[DEC]] = add nsw i32 [[A_0]], -1
; CHECK-NEXT:    br label [[FOR_COND]]
; CHECK:       for.end:
; CHECK-NEXT:    [[REM:%.*]] = srem i32 -1, [[A_0]]
; CHECK-NEXT:    ret i32 [[REM]]
;
entry:
  br label %for.cond

for.cond:
  %a.0 = phi i32 [ 2, %entry ], [ %dec, %for.inc ]
  %cmp = icmp sge i32 %a.0, 0
  br i1 %cmp, label %for.inc, label %for.end

for.inc:
  %dec = add nsw i32 %a.0, -1
  br label %for.cond

for.end:
  %rem = srem i32 -1, %a.0
  ret i32 %rem
}