optimizer: do not delete statements that may not :terminate (JuliaL…

…ang#52999)

Fixes JuliaLang#52991.
Currently this commit marks the test case added in JuliaLang#52954 as `broken`
since it has relied on the behavior of JuliaLang#52991.
I'm planning to add followup changes in a separate commit.

base/compiler/optimize.jl

@@ -48,9 +48,9 @@ const IR_FLAG_INACCESSIBLEMEM_OR_ARGMEM = one(UInt32) << 11
 const NUM_IR_FLAGS = 12 # sync with julia.h
 
 const IR_FLAGS_EFFECTS =
- IR_FLAG_CONSISTENT | IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW | IR_FLAG_NOUB
+ IR_FLAG_CONSISTENT | IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW | IR_FLAG_TERMINATES | IR_FLAG_NOUB
 
-const IR_FLAGS_REMOVABLE = IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+const IR_FLAGS_REMOVABLE = IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW | IR_FLAG_TERMINATES
 
 const IR_FLAGS_NEEDS_EA = IR_FLAG_EFIIMO | IR_FLAG_INACCESSIBLEMEM_OR_ARGMEM
 
@@ -69,6 +69,9 @@ function flags_for_effects(effects::Effects)
  if is_nothrow(effects)
  flags |= IR_FLAG_NOTHROW
  end
+ if is_terminates(effects)
+ flags |= IR_FLAG_TERMINATES
+ end
  if is_inaccessiblemem_or_argmemonly(effects)
  flags |= IR_FLAG_INACCESSIBLEMEM_OR_ARGMEM
  end
@@ -331,7 +334,8 @@ function stmt_effect_flags(𝕃ₒ::AbstractLattice, @nospecialize(stmt), @nospe
  consistent = is_consistent(effects)
  effect_free = is_effect_free(effects)
  nothrow = is_nothrow(effects)
- removable = effect_free & nothrow
+ terminates = is_terminates(effects)
+ removable = effect_free & nothrow & terminates
  return (consistent, removable, nothrow)
  elseif head === :new
  return new_expr_effect_flags(𝕃ₒ, args, src)
@@ -342,7 +346,8 @@ function stmt_effect_flags(𝕃ₒ::AbstractLattice, @nospecialize(stmt), @nospe
  consistent = is_consistent(effects)
  effect_free = is_effect_free(effects)
  nothrow = is_nothrow(effects)
- removable = effect_free & nothrow
+ terminates = is_terminates(effects)
+ removable = effect_free & nothrow & terminates
  return (consistent, removable, nothrow)
  elseif head === :new_opaque_closure
  length(args) < 4 && return (false, false, false)

base/dict.jl

@@ -868,34 +868,25 @@ struct PersistentDict{K,V} <: AbstractDict{K,V}
  @noinline function KeyValue.set(::Type{PersistentDict{K, V}}, ::Nothing, key, val) where {K, V}
  new{K, V}(HAMT.HAMT{K, V}(key => val))
  end
- @noinline @Base.assume_effects :effect_free function KeyValue.set(dict::PersistentDict{K, V}, key, val) where {K, V}
+ @noinline Base.@assume_effects :effect_free :terminates_globally KeyValue.set(
+ dict::PersistentDict{K, V}, key, val) where {K, V} = @inline _keyvalueset(dict, key, val)
+ @noinline Base.@assume_effects :nothrow :effect_free :terminates_globally KeyValue.set(
+ dict::PersistentDict{K, V}, key::K, val::V) where {K, V} = @inline _keyvalueset(dict, key, val)
+ global function _keyvalueset(dict::PersistentDict{K, V}, key, val) where {K, V}
  trie = dict.trie
  h = HAMT.HashState(key)
- found, present, trie, i, bi, top, hs = HAMT.path(trie, key, h, #=persistent=# true)
+ found, present, trie, i, bi, top, hs = HAMT.path(trie, key, h, #=persistent=#true)
  HAMT.insert!(found, present, trie, i, bi, hs, val)
  return new{K, V}(top)
  end
- @noinline @Base.assume_effects :nothrow :effect_free function KeyValue.set(dict::PersistentDict{K, V}, key::K, val::V) where {K, V}
+ @noinline Base.@assume_effects :effect_free :terminates_globally KeyValue.set(
+ dict::PersistentDict{K, V}, key) where {K, V} = @inline _keyvalueset(dict, key)
+ @noinline Base.@assume_effects :nothrow :effect_free :terminates_globally KeyValue.set(
+ dict::PersistentDict{K, V}, key::K) where {K, V} = @inline _keyvalueset(dict, key)
+ global function _keyvalueset(dict::PersistentDict{K, V}, key) where {K, V}
  trie = dict.trie
  h = HAMT.HashState(key)
- found, present, trie, i, bi, top, hs = HAMT.path(trie, key, h, #=persistent=# true)
- HAMT.insert!(found, present, trie, i, bi, hs, val)
- return new{K, V}(top)
- end
- @noinline @Base.assume_effects :effect_free function KeyValue.set(dict::PersistentDict{K, V}, key) where {K, V}
- trie = dict.trie
- h = HAMT.HashState(key)
- found, present, trie, i, bi, top, _ = HAMT.path(trie, key, h, #=persistent=# true)
- if found && present
- deleteat!(trie.data, i)
- HAMT.unset!(trie, bi)
- end
- return new{K, V}(top)
- end
- @noinline @Base.assume_effects :nothrow :effect_free function KeyValue.set(dict::PersistentDict{K, V}, key::K) where {K, V}
- trie = dict.trie
- h = HAMT.HashState(key)
- found, present, trie, i, bi, top, _ = HAMT.path(trie, key, h, #=persistent=# true)
+ found, present, trie, i, bi, top, _ = HAMT.path(trie, key, h, #=persistent=#true)
  if found && present
  deleteat!(trie.data, i)
  HAMT.unset!(trie, bi)

test/compiler/irpasses.jl

@@ -1836,3 +1836,48 @@ let code = Any[
  @test made_changes
  @test (ir[Core.SSAValue(length(ir.stmts))][:flag] & Core.Compiler.IR_FLAG_REFINED) != 0
 end
+
+# JuliaLang/julia#52991: statements that may not :terminate should not be deleted
+@noinline Base.@assume_effects :effect_free :nothrow function issue52991(n)
+ local s = 0
+ try
+ while true
+ yield()
+ if n - rand(1:10) > 0
+ s += 1
+ else
+ break
+ end
+ end
+ catch
+ end
+ return s
+end
+@test !Core.Compiler.is_removable_if_unused(Base.infer_effects(issue52991, (Int,)))
+let src = code_typed1((Int,)) do x
+ issue52991(x)
+ nothing
+ end
+ @test count(isinvoke(:issue52991), src.code) == 1
+end
+let t = @async begin
+ issue52991(11) # this call never terminates
+ nothing
+ end
+ sleep(1)
+ if istaskdone(t)
+ ok = false
+ else
+ ok = true
+ schedule(t, InterruptException(); error=true)
+ end
+ @test ok
+end
+
+# JuliaLang/julia47664
+@test !fully_eliminated() do
+ any(isone, Iterators.repeated(0))
+end
+@test !fully_eliminated() do
+ all(iszero, Iterators.repeated(0))
+end