added float32 schubfach algorithm; wip (#18155)

* added float32 schubfach algorithm; wip

* fixes #18418

compiler/ccgexprs.nim

@@ -2300,7 +2300,11 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
   of mInt64ToStr: genDollar(p, e, d, "#nimInt64ToStr($1)")
   of mBoolToStr: genDollar(p, e, d, "#nimBoolToStr($1)")
   of mCharToStr: genDollar(p, e, d, "#nimCharToStr($1)")
-  of mFloatToStr: genDollar(p, e, d, "#nimFloatToStr($1)")
+  of mFloatToStr:
+    if e[1].typ.skipTypes(abstractInst).kind == tyFloat32:
+      genDollar(p, e, d, "#nimFloat32ToStr($1)")
+    else:
+      genDollar(p, e, d, "#nimFloatToStr($1)")
   of mCStrToStr: genDollar(p, e, d, "#cstrToNimstr($1)")
   of mStrToStr, mUnown: expr(p, e[1], d)
   of mIsolate: genCall(p, e, d)

lib/system/dollars.nim

@@ -58,6 +58,10 @@ proc `$`*(x: float): string {.magic: "FloatToStr", noSideEffect.}
   ## The stringify operator for a float argument. Returns `x`
   ## converted to a decimal string.
 
+proc `$`*(x: float32): string {.magic: "FloatToStr", noSideEffect.}
+  ## The stringify operator for a float32 argument. Returns `x`
+  ## converted to a decimal string.
+
 proc `$`*(x: bool): string {.magic: "BoolToStr", noSideEffect.}
   ## The stringify operator for a boolean argument. Returns `x`
   ## converted to the string "false" or "true".