render float128 literals (#24182)

fixes #23639

Not sure if these are meant to be supported but it's better than
crashing.

compiler/renderer.nim

@@ -442,6 +442,11 @@ proc atom(g: TSrcGen; n: PNode): string =
       result = $n.floatVal & "\'f64"
     else:
       result = litAux(g, n, (cast[ptr int64](addr(n.floatVal)))[], 8) & "\'f64"
+  of nkFloat128Lit:
+    if n.flags * {nfBase2, nfBase8, nfBase16} == {}:
+      result = $n.floatVal & "\'f128"
+    else:
+      result = litAux(g, n, (cast[ptr int64](addr(n.floatVal)))[], 8) & "\'f128"
   of nkNilLit: result = "nil"
   of nkType:
     if (n.typ != nil) and (n.typ.sym != nil): result = n.typ.sym.name.s

tests/macros/tastrepr.nim

@@ -24,6 +24,9 @@ for i, (x, y) in pairs(data):
 var (a, b) = (1, 2)
 type
   A* = object
+
+var t04 = 1.0'f128
+t04 = 2.0'f128
 '''
 """
 
@@ -49,3 +52,7 @@ echoTypedAndUntypedRepr:
     discard
   var (a,b) = (1,2)
   type A* = object # issue #22933
+
+echoUntypedRepr:
+  var t04 = 1'f128
+  t04 = 2'f128