[PPL-devel] [GIT] ppl/ppl(floating_point): Never add a rounding error when casting the 0 value.

[Fabio Bossi]

Module: ppl/ppl
Branch: floating_point
Commit: 500981d998d62c82210b01b5c22994e9c7ef1f4b
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=500981d998d62c82210b01b5c22994e9c7ef1f4b

Author: Fabio Bossi <bossi at cs.unipr.it>
Date:   Tue Oct  5 10:51:03 2010 +0200

Never add a rounding error when casting the 0 value.

---

 src/linearize.hh |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/linearize.hh b/src/linearize.hh
index 8767f80..5374a93 100644
--- a/src/linearize.hh
+++ b/src/linearize.hh
@@ -600,8 +600,12 @@ cast_linearize(const Cast_Operator<Target>& cast_expr,
     if (!linearize(*cast_arg, oracle, lf_store, result))
       return false;
     if (!is_less_precise_than(analyzed_format,
-                              cast_arg->type().floating_point_format()))
-      // We are casting to a more precise format. Do not add errors.
+                              cast_arg->type().floating_point_format()) ||
+        result == FP_Linear_Form(FP_Interval_Type(0)))
+      /*
+        We are casting to a more precise format or casting the 0 value.
+        Do not add errors.
+      */
       return true;
   }
   else {
@@ -609,8 +613,12 @@ cast_linearize(const Cast_Operator<Target>& cast_expr,
     if (!oracle.get_integer_expr_value(*cast_arg, expr_value))
       return false;
     result = FP_Linear_Form(expr_value);
-    if (is_less_precise_than(Float<analyzer_format>::Binary::floating_point_format, analyzed_format))
-      // We are rounding to a less precise format. Do not add errors.
+    if (is_less_precise_than(Float<analyzer_format>::Binary::floating_point_format, analyzed_format) ||
+        result == FP_Linear_Form(FP_Interval_Type(0)))
+      /*
+        We are casting to a more precise format or casting the 0 value.
+        Do not add errors.
+      */
       return true;
   }