[Bug middle-end/60482] Loop optimization regression

jakub at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Mon Mar 10 17:31:00 GMT 2014


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60482

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The patch regresses the tree-ssa/ssa-ifcombine-10.c testcase, but that to me
just looks as tree-ssa-ifcombine.c being not enough flexible.  The difference
starting with VRP1 without -> with the patch is just:
@@ -27,14 +27,14 @@ f (int x, int a, int b)
   <bb 3>:
   _5 = x_3(D) & 4;
   if (_5 != 0)
-    goto <bb 4>;
-  else
     goto <bb 5>;
+  else
+    goto <bb 4>;

   <bb 4>:

   <bb 5>:
-  # t_1 = PHI <0(2), 3(4), 0(3)>
+  # t_1 = PHI <0(2), 3(3), 0(4)>
   return t_1;

which I'd say is quite unimportant difference ifcombine shouldn't care about,
but apparently it does.



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