include system/countbits_impl

lib/pure/bitops.nim

@@ -491,7 +491,7 @@ func countSetBits*(x: SomeInteger): int {.inline.} =
     doAssert countSetBits(0b0000_0011'u8) == 2
     doAssert countSetBits(0b1010_1010'u8) == 4
 
-  result = countSetBitsImpl(x)
+  result = countSetBitsSysimpl(x)
 
 func popcount*(x: SomeInteger): int {.inline.} =
   ## Alias for `countSetBits <#countSetBits,SomeInteger>`_ (Hamming weight).

lib/pure/math.nim

@@ -58,7 +58,6 @@ import std/private/since
                        # of the standard library!
 
 import std/[bitops, fenv]
-import system/countbits_impl
 
 when defined(nimPreviewSlimSystem):
   import std/assertions
@@ -1302,7 +1301,7 @@ func gcd*[T](x, y: T): T =
     swap x, y
   abs x
 
-when useBuiltins:
+when not defined(noIntrinsicsBitOpts):
   ## this func uses bitwise comparisons from C compilers, which are not always available.
   func gcd*(x, y: SomeInteger): SomeInteger =
     ## Computes the greatest common (positive) divisor of `x` and `y`,

lib/std/private/bitops_utils.nim

@@ -1,3 +1,10 @@
+const useBuiltins = not defined(noIntrinsicsBitOpts)
+const noUndefined = defined(noUndefinedBitOpts)
+const useGCC_builtins = (defined(gcc) or defined(llvm_gcc) or
+                         defined(clang)) and useBuiltins
+const useICC_builtins = defined(icc) and useBuiltins
+const useVCC_builtins = defined(vcc) and useBuiltins
+
 template forwardImpl(impl, arg) {.dirty.} =
   when sizeof(x) <= 4:
     when x is SomeSignedInt:

lib/system.nim

@@ -2340,7 +2340,7 @@ when not defined(js):
 
 
 when notJSnotNims:
-  import system/countbits_impl
+  include system/countbits_impl
   include "system/sets"
 
   when defined(gogc):

lib/system/countbits_impl.nim

@@ -11,13 +11,7 @@
 
 include std/private/bitops_utils
 
-const useBuiltins* = not defined(noIntrinsicsBitOpts)
-const noUndefined* = defined(noUndefinedBitOpts)
-const useGCC_builtins* = (defined(gcc) or defined(llvm_gcc) or
-                         defined(clang)) and useBuiltins
-const useICC_builtins* = defined(icc) and useBuiltins
-const useVCC_builtins* = defined(vcc) and useBuiltins
-const arch64* = sizeof(int) == 8
+const arch64 = sizeof(int) == 8
 
 template countBitsImpl(n: uint32): int =
   # generic formula is from: https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
@@ -60,7 +54,7 @@ elif useICC_builtins:
       importc: "_popcnt64", header: "<immintrin.h>".}
 
 
-func countSetBitsImpl*(x: SomeInteger): int {.inline.} =
+func countSetBitsImpl(x: SomeInteger): int {.inline.} =
   ## Counts the set bits in an integer (also called `Hamming weight`:idx:).
   # TODO: figure out if ICC support _popcnt32/_popcnt64 on platform without POPCNT.
   # like GCC and MSVC
@@ -85,3 +79,6 @@ func countSetBitsImpl*(x: SomeInteger): int {.inline.} =
     else:
       when sizeof(x) <= 4: result = countBitsImpl(x.uint32)
       else: result = countBitsImpl(x.uint64)
+
+func countSetBitsSysimpl*(x: SomeInteger): int {.inline.} =
+  result = countSetBitsImpl(x)