From 5e7b6dd090791ca545897d9625a82cae34c116b1 Mon Sep 17 00:00:00 2001
From: Shuhei Kadowaki <40514306+aviatesk@users.noreply.github.com>
Date: Mon, 14 Feb 2022 10:06:55 +0900
Subject: [PATCH] inference: look for `:terminate_globally` override in
 backedge termination check (#44106)

Now we can "fix" #41694:
```julia
Base.@assume_effects :terminates_globally function issue41694(x)
    res = 1
    1 < x < 20 || throw("bad")
    while x > 1
        res *= x
        x -= 1
    end
    return res
end
@test fully_eliminated() do
    issue41694(2)
end
```
---
 base/compiler/abstractinterpretation.jl |  9 ++++++---
 base/compiler/types.jl                  |  4 ++--
 test/compiler/inline.jl                 | 14 ++++++++++++++
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/base/compiler/abstractinterpretation.jl b/base/compiler/abstractinterpretation.jl
index 219208ab3b80d..342b7e7d5e13a 100644
--- a/base/compiler/abstractinterpretation.jl
+++ b/base/compiler/abstractinterpretation.jl
@@ -1878,7 +1878,7 @@ function abstract_eval_statement(interp::AbstractInterpreter, @nospecialize(e),
                 effects.consistent ? ALWAYS_TRUE : TRISTATE_UNKNOWN,
                 effects.effect_free ? ALWAYS_TRUE : TRISTATE_UNKNOWN,
                 effects.nothrow ? ALWAYS_TRUE : TRISTATE_UNKNOWN,
-                effects.terminates ? ALWAYS_TRUE : TRISTATE_UNKNOWN,
+                effects.terminates_globally ? ALWAYS_TRUE : TRISTATE_UNKNOWN,
             ))
         else
             tristate_merge!(sv, Effects())
@@ -2052,8 +2052,11 @@ end
 function handle_control_backedge!(frame::InferenceState, from::Int, to::Int)
     if from > to
         def = frame.linfo.def
-        if isa(def, Method) && decode_effects_override(def.purity).terminates_locally
-            return nothing
+        if isa(def, Method)
+            effects = decode_effects_override(def.purity)
+            if effects.terminates_globally || effects.terminates_locally
+                return nothing
+            end
         end
         tristate_merge!(frame, Effects(EFFECTS_TOTAL, terminates=TRISTATE_UNKNOWN))
     end
diff --git a/base/compiler/types.jl b/base/compiler/types.jl
index cebb560a2010b..3b19b509f11bf 100644
--- a/base/compiler/types.jl
+++ b/base/compiler/types.jl
@@ -89,7 +89,7 @@ struct EffectsOverride
     consistent::Bool
     effect_free::Bool
     nothrow::Bool
-    terminates::Bool
+    terminates_globally::Bool
     terminates_locally::Bool
 end
 
@@ -98,7 +98,7 @@ function encode_effects_override(eo::EffectsOverride)
     eo.consistent && (e |= 0x01)
     eo.effect_free && (e |= 0x02)
     eo.nothrow && (e |= 0x04)
-    eo.terminates && (e |= 0x08)
+    eo.terminates_globally && (e |= 0x08)
     eo.terminates_locally && (e |= 0x10)
     e
 end
diff --git a/test/compiler/inline.jl b/test/compiler/inline.jl
index 8a3d88fb9d1e0..9347acc83f13f 100644
--- a/test/compiler/inline.jl
+++ b/test/compiler/inline.jl
@@ -1055,3 +1055,17 @@ function f_call_invoke_callback(f::FCallback)
     return nothing
 end
 @test !fully_eliminated(f_call_invoke_callback, Tuple{FCallback})
+
+# https://github.com/JuliaLang/julia/issues/41694
+Base.@assume_effects :terminates_globally function issue41694(x)
+    res = 1
+    1 < x < 20 || throw("bad")
+    while x > 1
+        res *= x
+        x -= 1
+    end
+    return res
+end
+@test fully_eliminated() do
+    issue41694(2)
+end