Mimic Julia behaviour

Author: christiangnrd

src/device/intrinsics/math.jl

@@ -9,10 +9,17 @@ using Base.Math: throw_complex_domainerror
 # - consider emitting LLVM intrinsics and lowering those in the back-end
 
 ### Constants
-@device_override Core.Float32(::typeof(π), ::RoundingMode) = reinterpret(Float32, 0x40490fdb) # 3.1415927f0 reinterpret(UInt32,Float32(reinterpret(Float64,0x400921FB60000000)))
-@device_override Core.Float16(::typeof(π), ::RoundingMode) = reinterpret(Float16, 0x4248)     # Float16(3.14)
-@device_override Core.Float32(::typeof(ℯ), ::RoundingMode) = reinterpret(Float32, 0x402df854) # 2.7182817f0 reinterpret(UInt32,Float32(reinterpret(Float64,0x4005BF0A80000000)))
-@device_override Core.Float16(::typeof(ℯ), ::RoundingMode) = reinterpret(Float16, 0x4170)     # Float16(2.719)
+# π
+@device_override Core.Float32(::typeof(π), ::RoundingMode) = reinterpret(Float32, 0x40490fdb)        # 3.1415927f0 reinterpret(UInt32,Float32(reinterpret(Float64,0x400921FB60000000)))
+@device_override Core.Float32(::typeof(π), ::RoundingMode{:Down}) = reinterpret(Float32, 0x40490fda) # 3.1415925f0 prevfloat(reinterpret(UInt32,Float32(reinterpret(Float64,0x400921FB60000000))))
+@device_override Core.Float16(::typeof(π), ::RoundingMode{:Up}) = reinterpret(Float16, 0x4249)       # Float16(3.143)
+@device_override Core.Float16(::typeof(π), ::RoundingMode) = reinterpret(Float16, 0x4248)            # Float16(3.14)
+
+# ℯ
+@device_override Core.Float32(::typeof(ℯ), ::RoundingMode{:Up}) = reinterpret(Float32, 0x402df855)   # 2.718282f0 nextfloat(reinterpret(UInt32,Float32(reinterpret(Float64,0x4005BF0A80000000))))
+@device_override Core.Float32(::typeof(ℯ), ::RoundingMode) = reinterpret(Float32, 0x402df854)        # 2.7182817f0 reinterpret(UInt32,Float32(reinterpret(Float64,0x4005BF0A80000000)))
+@device_override Core.Float16(::typeof(ℯ), ::RoundingMode) = reinterpret(Float16, 0x4170)            # Float16(2.719)
+@device_override Core.Float16(::typeof(ℯ), ::RoundingMode{:Down}) = reinterpret(Float16, 0x416f)     # Float16(2.717)
 
 ### Common Intrinsics
 @device_function clamp_fast(x::Float32, minval::Float32, maxval::Float32) = ccall("extern air.fast_clamp.f32", llvmcall, Cfloat, (Cfloat, Cfloat, Cfloat), x, minval, maxval)

test/device/intrinsics/math.jl

@@ -312,11 +312,31 @@ end
         @test occursin(Regex("@air\\.sign\\.f$(8*sizeof(T))"), ir)
     end
 
-    let # "issue551"
-        mtl_pi = only(Array(T.(MtlArray([π]), RoundNearest)))
-        @test mtl_pi == T(π)
-        mtl_ℯ = only(Array(T.(MtlArray([ℯ]), RoundNearest)))
-        @test mtl_ℯ == T(ℯ)
+    # Borrowed from the Julia "Irrationals compared with Rationals and Floats" testset
+    @testset "Comparisons with $irr" for irr in (π, ℯ)
+        function convert_test_32(res)
+            res[1] = Float32(irr,RoundDown) < irr
+            res[2] = Float32(irr,RoundUp) > irr
+            res[3] = !(Float32(irr,RoundDown) > irr)
+            res[4] = !(Float32(irr,RoundUp) < irr)
+            return nothing
+        end
+
+        res_32 = MtlArray(zeros(Bool,4))
+        Metal.@sync @metal convert_test_32(res_32)
+        @test all(Array(res_32))
+
+        function convert_test_16(res)
+            res[1] = Float16(irr,RoundDown) < irr
+            res[2] = Float16(irr,RoundUp) > irr
+            res[3] = !(Float16(irr,RoundDown) > irr)
+            res[4] = !(Float16(irr,RoundUp) < irr)
+            return nothing
+        end
+
+        res_16 = MtlArray(zeros(Bool,4))
+        Metal.@sync @metal convert_test_16(res_16)
+        @test all(Array(res_16))
     end
 end
 end