Skip to content
Snippets Groups Projects
  1. Oct 16, 2010
  2. Oct 14, 2010
  3. Oct 13, 2010
  4. Oct 12, 2010
  5. Oct 10, 2010
  6. Oct 08, 2010
  7. Oct 07, 2010
  8. Oct 01, 2010
  9. Sep 30, 2010
  10. Sep 29, 2010
  11. Sep 28, 2010
  12. Sep 27, 2010
  13. Sep 25, 2010
    • Owen Anderson's avatar
      LoadPRE was not properly checking that the load it was PRE'ing post-dominated... · b590a927
      Owen Anderson authored
      LoadPRE was not properly checking that the load it was PRE'ing post-dominated the block it was being hoisted to.
      Splitting critical edges at the merge point only addressed part of the issue; it is also possible for non-post-domination
      to occur when the path from the load to the merge has branches in it.  Unfortunately, full anticipation analysis is
      time-consuming, so for now approximate it.  This is strictly more conservative than real anticipation, so we will miss
      some cases that real PRE would allow, but we also no longer insert loads into paths where they didn't exist before. :-)
      
      This is a very slight net positive on SPEC for me (0.5% on average).  Most of the benchmarks are largely unaffected, but
      when it pays off it pays off decently: 181.mcf improves by 4.5% on my machine.
      
      llvm-svn: 114785
      b590a927
Loading