[Bug middle-end/40021] [4.5 Regression] Revision 146817 miscompiled DAXPY in BLAS

[hjl dot tools at gmail dot com]

------- Comment #9 from hjl dot tools at gmail dot com  2009-05-05 16:28 -------
(In reply to comment #8)
> Created an attachment (id=17803)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17803&action=view) [edit]
> fix for the problem
> 
> I'm regstrapping this patch, it fixes the problem in the testcase.
> 

Shouldn't

+       {
+         rtx insn;
+         remove_edge (false_edge);
+         /* Now, we have a single successor block, if we have insns to
+            insert on the remaining edge we potentially will insert
+            it at the end of this block (if the dest block isn't feasible)
+            in order to avoid splitting the edge.  This insertion will take
+            place in front of the last jump.  But we might have emitted
+            multiple jumps (conditional and one unconditional) to the
+            same destination.  Inserting in front of the last one then
+            is a problem.  See PR 40021.  We fix this by deleting all
+            jumps except the last unconditional one.  */
+         insn = PREV_INSN (get_last_insn ());
+         /* Make sure we have an unconditional jump.  Otherwise we're
+            confused.  */
+         gcc_assert (JUMP_P (insn) && !any_condjump_p (insn));
+         for (insn = PREV_INSN (insn); insn != BB_HEAD (bb);)
+           {
+             insn = PREV_INSN (insn);
+             if (JUMP_P (NEXT_INSN (insn)))
+               delete_insn (NEXT_INSN (insn));
+           }
+       }

in a standalone function since it is used twice?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40021