Fix tests on AArch64

Author: vchuravy

test/intrinsics.jl

@@ -169,11 +169,21 @@ end
     @test_intrinsic Core.Intrinsics.fptoui UInt Float16(3.3) UInt(3)
 end
 
-extendhfsf2(x::Float16) = ccall("extern __extendhfsf2", llvmcall, Float32, (Float16,), x)
-gnu_h2f_ieee(x::Float16) = ccall("extern __gnu_h2f_ieee", llvmcall, Float32, (Float16,), x)
-truncsfhf2(x::Float32) = ccall("extern __truncsfhf2", llvmcall, Float16, (Float32,), x)
-gnu_f2h_ieee(x::Float32) = ccall("extern __gnu_f2h_ieee", llvmcall, Float16, (Float32,), x)
-truncdfhf2(x::Float64) = ccall("extern __truncdfhf2", llvmcall, Float16, (Float64,), x)
+if Sys.ARCH == :aarch64
+    # On AArch64 we are following the `_Float16` ABI. Buthe these functions expect `Int16`.
+    # TODO: SHould we have `Chalf == Int16` and `Cfloat16 == Float16`?
+    extendhfsf2(x::Float16) = ccall("extern __extendhfsf2", llvmcall, Float32, (Int16,), reinterpret(Int16, x))
+    gnu_h2f_ieee(x::Float16) = ccall("extern __gnu_h2f_ieee", llvmcall, Float32, (Int16,), reinterpret(Int16, x))
+    truncsfhf2(x::Float32) = reinterpret(Float16, ccall("extern __truncsfhf2", llvmcall, Int16, (Float32,), x))
+    gnu_f2h_ieee(x::Float32) = reinterpret(Float16, ccall("extern __gnu_f2h_ieee", llvmcall, Int16, (Float32,), x))
+    truncdfhf2(x::Float64) = reinterpret(Float16, ccall("extern __truncdfhf2", llvmcall, Int16, (Float64,), x))
+else
+    extendhfsf2(x::Float16) = ccall("extern __extendhfsf2", llvmcall, Float32, (Float16,), x)
+    gnu_h2f_ieee(x::Float16) = ccall("extern __gnu_h2f_ieee", llvmcall, Float32, (Float16,), x)
+    truncsfhf2(x::Float32) = ccall("extern __truncsfhf2", llvmcall, Float16, (Float32,), x)
+    gnu_f2h_ieee(x::Float32) = ccall("extern __gnu_f2h_ieee", llvmcall, Float16, (Float32,), x)
+    truncdfhf2(x::Float64) = ccall("extern __truncdfhf2", llvmcall, Float16, (Float64,), x)
+end
 
 @testset "Float16 intrinsics (crt)" begin
     @test extendhfsf2(Float16(3.3)) == 3.3007812f0