From 3b448f597344109183c2436d477deed0ed820d6f Mon Sep 17 00:00:00 2001
From: Xavier Leroy <xavier.leroy@college-de-france.fr>
Date: Tue, 27 Apr 2021 09:27:18 +0200
Subject: Support __builtin_expect

Not yet used for optimizations.

Actually, __builtin_expect is removed during C2C conversion, otherwise
the conversion to type "long" produces inefficient code on 64-bit platforms.
---
 cfrontend/C2C.ml | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'cfrontend')

diff --git a/cfrontend/C2C.ml b/cfrontend/C2C.ml
index 8b205d19..1256043e 100644
--- a/cfrontend/C2C.ml
+++ b/cfrontend/C2C.ml
@@ -271,6 +271,8 @@ let builtins_generic = {
   (* Optimization hints *)
     "__builtin_unreachable",
         (TVoid [], [], false);
+    "__builtin_expect",
+        (TInt(ILong, []), [TInt(ILong, []); TInt(ILong, [])], false);
   (* Helper functions for int64 arithmetic *)
     "__compcert_i64_dtos",
         (TInt(ILongLong, []),
@@ -992,6 +994,9 @@ let rec convertExpr env e =
       ewrap (Ctyping.eselection (convertExpr env arg1)
                                 (convertExpr env arg2) (convertExpr env arg3))
 
+  | C.ECall({edesc = C.EVar {name = "__builtin_expect"}}, [arg1; arg2]) ->
+      convertExpr env arg1
+
   | C.ECall({edesc = C.EVar {name = "printf"}}, args)
     when !Clflags.option_interp ->
       let targs = convertTypArgs env [] args
-- 
cgit