https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64853

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-01-29
                 CC|                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |5.0
            Summary|wrong code at -Os and above |[5 Regression] wrong code
                   |on x86_64-linux-gnu         |at -Os and above on
                   |                            |x86_64-linux-gnu
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This started with r217560, the first difference is during VRP2:
 Visiting statement:
 _13 = (signed char) g_68;
+Match-and-simplified (signed char) g_68 to -56(OVF)
 Found new range for _13: [-56, -56]
and various others, leading to
-_10: ~[1, 254]
+_10: [255, +INF]
 .MEM_11: VARYING
-g_12: [0, 255]
-_13: VARYING
+g_12: [255, 255]
+_13: [-56, -1]
etc.  Haven't checked if the changes are correct or not.

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