fix IEEE compliancy in floating point min/max reductions on LLVM vers…

…ion that supports it (#130)

Co-authored-by: KristofferC <[email protected]>

src/LLVM_intrinsics.jl

@@ -806,9 +806,11 @@ end
 # Horizontal reductions (LLVM 9) #
 ##################################
 
+const SUPPORTS_FMAXIMUM_FMINIMUM = Base.libllvm_version >= v"18"
+
 const HORZ_REDUCTION_OPS_FLOAT = [
-    :fmax
-    :fmin
+    SUPPORTS_FMAXIMUM_FMINIMUM ? :fmaximum : :fmax
+    SUPPORTS_FMAXIMUM_FMINIMUM ? :fminimum : :fmin
 ]
 
 const HORZ_REDUCTION_OPS_INT = [

src/simdvec.jl

@@ -458,10 +458,10 @@ const HORZ_REDUCTION_OPS = [
     (|   , Union{IntegerTypes, Bool}  , Intrinsics.reduce_or)
     (max , IntTypes      , Intrinsics.reduce_smax)
     (max , UIntTypes     , Intrinsics.reduce_umax)
-    (max , FloatingTypes , Intrinsics.reduce_fmax)
+    (max , FloatingTypes , Intrinsics.SUPPORTS_FMAXIMUM_FMINIMUM ? Intrinsics.reduce_fmaximum : Intrinsics.reduce_fmax)
     (min , IntTypes      , Intrinsics.reduce_smin)
     (min , UIntTypes     , Intrinsics.reduce_umin)
-    (min , FloatingTypes , Intrinsics.reduce_fmin)
+    (min , FloatingTypes , Intrinsics.SUPPORTS_FMAXIMUM_FMINIMUM ? Intrinsics.reduce_fminimum : Intrinsics.reduce_fmin)
     (+   , Union{IntegerTypes, Bool}  , Intrinsics.reduce_add)
     (*   , IntegerTypes  , Intrinsics.reduce_mul)
     (+   , FloatingTypes , Intrinsics.reduce_fadd)

test/runtests.jl

@@ -354,6 +354,15 @@ llvm_ir(f, args) = sprint(code_llvm, f, Base.typesof(args...))
 
         @test sum(Vec{3,Float64}(1)) === 3.0
         @test prod(Vec{5,Float64}(2)) === 32.0
+
+        # Floating point reduce IEEEE # https://github.com/eschnett/SIMD.jl/issues/129
+        if SIMD.Intrinsics.SUPPORTS_FMAXIMUM_FMINIMUM
+            t = (1.0, 2.0, NaN, 0.5)
+            tv = SIMD.Vec(t)
+
+            @test isnan(reduce(min, t))
+            @test isnan(reduce(min, tv))
+        end
     end
 
     @testset "Load and store functions" begin