[Bug optimization/13301] [tree-ssa] deficiency in jump threading

["law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From law at redhat dot com  2003-12-04 22:19 -------
Subject: Re:  [tree-ssa] deficiency in jump threading 

In message <20031204111206.14420.qmail@sources.redhat.com>, "rth at redhat dot 
com" writes:
 >
 >------- Additional Comments From rth at redhat dot com  2003-12-04 11:12 ----
 >---
 >Subject: Re:  [tree-ssa] deficiency in jump threading
 >
 >On Thu, Dec 04, 2003 at 10:45:19AM -0000, pinskia at gcc dot gnu dot org wrot
 >e:
 >> I do not know if the tree jump threading supports switch tables at all...
 >
 >It does, but that's not the problem.  Past the switch, the 
 >"return NULL" gets compiled to "retval = NULL; goto retloc;"
 >and we must thread *that* goto with the if condition that
 >immediately follows.
 >
 >> but it would be good to know the real case of this bug.
 >
 >I have no doubt that there is a PHI node in the block that
 >contains the if condition, and that it is causing the 
 >existing jump threading pass to give up.
 >
 >I also happen to know that Jeff said that he is working on
 >this type of problem, so I assigned the PR to him.
Yup.  I've gone back to jump threading from the not-so-brief poking at
memory consumption issues. 

jeff




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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13301