mark fastmath operations as not :consistent (JuliaLang#46143)

We also need to mark `muladd` as not IPO-`:consistent, but it requires
to revive JuliaLang#31193 to preserve the currently available optimizations so
I left it as TODO for now.

Author: aviatesk

base/compiler/tfuncs.jl

@@ -1875,6 +1875,30 @@ const _ARGMEM_BUILTINS = Any[
     swapfield!,
 ]
 
+const _INCONSISTENT_INTRINSICS = Any[
+    Intrinsics.pointerref,      # this one is volatile
+    Intrinsics.arraylen,        # this one is volatile
+    Intrinsics.sqrt_llvm_fast,  # this one may differ at runtime (by a few ulps)
+    Intrinsics.have_fma,        # this one depends on the runtime environment
+    Intrinsics.cglobal,         # cglobal lookup answer changes at runtime
+    # ... and list fastmath intrinsics:
+    # join(string.("Intrinsics.", sort(filter(endswith("_fast")∘string, names(Core.Intrinsics)))), ",\n")
+    Intrinsics.add_float_fast,
+    Intrinsics.div_float_fast,
+    Intrinsics.eq_float_fast,
+    Intrinsics.le_float_fast,
+    Intrinsics.lt_float_fast,
+    Intrinsics.mul_float_fast,
+    Intrinsics.ne_float_fast,
+    Intrinsics.neg_float_fast,
+    Intrinsics.rem_float_fast,
+    Intrinsics.sqrt_llvm_fast,
+    Intrinsics.sub_float_fast
+    # TODO needs to revive #31193 to mark this as inconsistent to be accurate
+    # while preserving the currently optimizations for many math operations
+    # Intrinsics.muladd_float,    # this is not interprocedurally consistent
+]
+
 const _SPECIAL_BUILTINS = Any[
     Core._apply_iterate,
 ]
@@ -2142,13 +2166,7 @@ function intrinsic_effects(f::IntrinsicFunction, argtypes::Vector{Any})
         return Effects()
     end
 
-    consistent = !(
-        f === Intrinsics.pointerref ||      # this one is volatile
-        f === Intrinsics.arraylen ||        # this one is volatile
-        f === Intrinsics.sqrt_llvm_fast ||  # this one may differ at runtime (by a few ulps)
-        f === Intrinsics.have_fma ||        # this one depends on the runtime environment
-        f === Intrinsics.cglobal            # cglobal lookup answer changes at runtime
-        ) ? ALWAYS_TRUE : ALWAYS_FALSE
+    consistent = contains_is(_INCONSISTENT_INTRINSICS, f) ? ALWAYS_FALSE : ALWAYS_TRUE
     effect_free = !(f === Intrinsics.pointerset) ? ALWAYS_TRUE : ALWAYS_FALSE
     nothrow = (!(!isempty(argtypes) && isvarargtype(argtypes[end])) && intrinsic_nothrow(f, argtypes))
 

test/compiler/effects.jl

@@ -301,6 +301,9 @@ end |> !Core.Compiler.is_nothrow
     Core.svec(nothing, 1, "foo")
 end |> Core.Compiler.is_consistent
 
+# fastmath operations are inconsistent
+@test !Core.Compiler.is_consistent(Base.infer_effects((a,b)->@fastmath(a+b), (Float64,Float64)))
+
 # issue 46122: @assume_effects for @ccall
 @test Base.infer_effects((Vector{Int},)) do a
     Base.@assume_effects :effect_free @ccall jl_array_ptr(a::Any)::Ptr{Int}