[LLVMbugs] [Bug 174] [taildup] Tail duplication does not update SSA form correctly

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=174

sabre at nondot.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED



------- Additional Comments From sabre at nondot.org  2004-02-01 01:28 -------
This patch:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20040126/011043.html

... "fixes" the problem by disabling tail duplication in any "tricky" case. 
This is overkill, and it pessimizes the optimization unfortunately, but there is
no good way to fix this without a nice implementation of an incremental
dominator updating utility (which is enhancement request Bug 217).

Since this bug is finally fixed, this patch can now go in:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20040126/011044.html

Which dramatically improves the performance of programs compiled with LLVM.  For
example, it improves the stepanov benchmark from 55.56 mega-additions/sec to
98.04 Ma/s.  It also improves the oopack/iterator benchmark from 338.3MFLOPS/s
to 1103.4MFLOPS/s.  Less noteworthy, it improves oopack/matrix from 573 -> 641
MFLOPS/s.

-Chris




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