auto merge of #13415 : thestinger/rust/f128, r=alexcrichton

This currently requires linking against a library like libquadmath (or
libgcc), because compiler-rt barely has any support for this and most
hardware does not yet have 128-bit precision floating point. For this
reason, it's currently hidden behind a feature gate.

When compiler-rt is updated to trunk, some tests can be added for
constant evaluation since there will be support for the comparison
operators.

Closes #13381

4 files changed, 12 insertions, 5 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 2b6f94e6bf5..a6146e0eaea 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -730,6 +730,7 @@ impl fmt::Show for UintTy {
 pub enum FloatTy {
     TyF32,
     TyF64,
+    TyF128
 }
 
 impl fmt::Show for FloatTy {
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
index 437f865b449..adb97af7490 100644
--- a/src/libsyntax/ast_util.rs
+++ b/src/libsyntax/ast_util.rs
@@ -187,7 +187,7 @@ pub fn uint_ty_max(t: UintTy) -> u64 {
 }
 
 pub fn float_ty_to_str(t: FloatTy) -> ~str {
-    match t { TyF32 => "f32".to_owned(), TyF64 => "f64".to_owned() }
+    match t { TyF32 => "f32".to_owned(), TyF64 => "f64".to_owned(), TyF128 => "f128".to_owned() }
 }
 
 pub fn is_call_expr(e: @Expr) -> bool {
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index 7d86b988077..68b0ef40b16 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -436,7 +436,8 @@ fn mk_token(cx: &ExtCtxt, sp: Span, tok: &token::Token) -> @ast::Expr {
         LIT_FLOAT(fident, fty) => {
             let s_fty = match fty {
                 ast::TyF32 => "TyF32".to_owned(),
-                ast::TyF64 => "TyF64".to_owned()
+                ast::TyF64 => "TyF64".to_owned(),
+                ast::TyF128 => "TyF128".to_owned()
             };
             let e_fty = cx.expr_ident(sp, id_ext(s_fty));
 
diff --git a/src/libsyntax/parse/lexer.rs b/src/libsyntax/parse/lexer.rs
index ff087d95e50..992d289b4e9 100644
--- a/src/libsyntax/parse/lexer.rs
+++ b/src/libsyntax/parse/lexer.rs
@@ -593,10 +593,15 @@ fn scan_number(c: char, rdr: &mut StringReader) -> token::Token {
             /* FIXME (#2252): if this is out of range for either a
             32-bit or 64-bit float, it won't be noticed till the
             back-end.  */
-        } else {
-            fatal_span(rdr, start_bpos, rdr.last_pos,
-                       "expected `f32` or `f64` suffix".to_owned());
+        } else if c == '1' && n == '2' && nextnextch(rdr).unwrap_or('\x00') == '8' {
+            bump(rdr);
+            bump(rdr);
+            bump(rdr);
+            check_float_base(rdr, start_bpos, rdr.last_pos, base);
+            return token::LIT_FLOAT(str_to_ident(num_str.as_slice()), ast::TyF128);
         }
+        fatal_span(rdr, start_bpos, rdr.last_pos,
+                   "expected `f32`, `f64` or `f128` suffix".to_owned());
     }
     if is_float {
         check_float_base(rdr, start_bpos, rdr.last_pos, base);