From cd68571afa8bde3fca5fa1277047ce10e31e8eff Mon Sep 17 00:00:00 2001
From: Jeff Bezanson <jeff.bezanson@gmail.com>
Date: Mon, 14 Jun 2021 15:41:02 -0400
Subject: [PATCH] fix #34288, method errors in nothrow inference of division
 intrinsics (#41178)

---
 base/compiler/tfuncs.jl    | 9 ++++++---
 test/compiler/inference.jl | 4 ++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/base/compiler/tfuncs.jl b/base/compiler/tfuncs.jl
index 56fe9d1591848..57b86bf504217 100644
--- a/base/compiler/tfuncs.jl
+++ b/base/compiler/tfuncs.jl
@@ -1568,6 +1568,10 @@ end
 
 # Query whether the given intrinsic is nothrow
 
+_iszero(x) = x === Intrinsics.xor_int(x, x)
+_isneg1(x) = _iszero(Intrinsics.not_int(x))
+_istypemin(x) = !_iszero(x) && Intrinsics.neg_int(x) === x
+
 function intrinsic_nothrow(f::IntrinsicFunction, argtypes::Array{Any, 1})
     # First check that we have the correct number of arguments
     iidx = Int(reinterpret(Int32, f::IntrinsicFunction)) + 1
@@ -1594,11 +1598,10 @@ function intrinsic_nothrow(f::IntrinsicFunction, argtypes::Array{Any, 1})
             return false
         end
         den_val = argtypes[2].val
-        den_val !== zero(typeof(den_val)) || return false
+        _iszero(den_val) && return false
         f !== Intrinsics.checked_sdiv_int && return true
         # Nothrow as long as we additionally don't do typemin(T)/-1
-        return den_val !== -1 || (isa(argtypes[1], Const) &&
-            argtypes[1].val !== typemin(typeof(den_val)))
+        return !_isneg1(den_val) || (isa(argtypes[1], Const) && !_istypemin(argtypes[1].val))
     end
     if f === Intrinsics.pointerref
         # Nothrow as long as the types are ok. N.B.: dereferencability is not
diff --git a/test/compiler/inference.jl b/test/compiler/inference.jl
index 76fd93bb75763..52602a58c517b 100644
--- a/test/compiler/inference.jl
+++ b/test/compiler/inference.jl
@@ -3319,3 +3319,7 @@ end |> first === Tuple{Int, String}
 # issue #40804
 @test Base.return_types(()) do; ===(); end == Any[Union{}]
 @test Base.return_types(()) do; typeassert(); end == Any[Union{}]
+
+primitive type UInt24ish 24 end
+f34288(x) = Core.Intrinsics.checked_sdiv_int(x, Core.Intrinsics.trunc_int(UInt24ish, 0))
+@test Base.return_types(f34288, (UInt24ish,)) == Any[UInt24ish]