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  1. Feb 03, 2006
    • Chris Lattner's avatar
      the X86 backend no longer needs to delete its own noop copies · a1eac9b9
      Chris Lattner authored
      llvm-svn: 25923
      a1eac9b9
    • Chris Lattner's avatar
      Add code that checks for noop copies, which triggers when either: · 1ef239af
      Chris Lattner authored
      1. a target doesn't know how to fold load/stores into copies, or
      2. the spiller rewrites the input to a copy to the same register as the dest
         instead of to the reloaded reg.
      
      This will be moved/improved in the near future, but allows elimination of
      some ancient x86 hacks.  This eliminates 92 copies from SMG2000 on X86 and
      163 copies from 252.eon.
      
      llvm-svn: 25922
      1ef239af
    • Chris Lattner's avatar
      Add a note · f0a2d66d
      Chris Lattner authored
      llvm-svn: 25921
      f0a2d66d
    • Evan Cheng's avatar
      Added case HANDLENODE to getOperationName(). · 02b5b9cd
      Evan Cheng authored
      llvm-svn: 25920
      02b5b9cd
    • Chris Lattner's avatar
      Physregs may hold multiple stack slot values at the same time. Keep track · b7f24de4
      Chris Lattner authored
      of this, and use it to our advantage (bwahahah).  This allows us to eliminate another
      60 instructions from smg2000 on PPC (probably significantly more on X86).  A common
      old-new diff looks like this:
      
              stw r2, 3304(r1)
      -       lwz r2, 3192(r1)
              stw r2, 3300(r1)
      -       lwz r2, 3192(r1)
              stw r2, 3296(r1)
      -       lwz r2, 3192(r1)
              stw r2, 3200(r1)
      -       lwz r2, 3192(r1)
              stw r2, 3196(r1)
      -       lwz r2, 3192(r1)
      +       or r2, r2, r2
              stw r2, 3188(r1)
      
      and
      
      -       lwz r31, 604(r1)
      -       lwz r13, 604(r1)
      -       lwz r14, 604(r1)
      -       lwz r15, 604(r1)
      -       lwz r16, 604(r1)
      -       lwz r30, 604(r1)
      +       or r31, r30, r30
      +       or r13, r30, r30
      +       or r14, r30, r30
      +       or r15, r30, r30
      +       or r16, r30, r30
      +       or r30, r30, r30
      
      Removal of the R = R copies is coming next...
      
      llvm-svn: 25919
      b7f24de4
    • Chris Lattner's avatar
      update a note · 9b178ce2
      Chris Lattner authored
      llvm-svn: 25918
      9b178ce2
    • Chris Lattner's avatar
      Fix a deficiency in the spiller that Evan noticed. In particular, consider · f3aef1b0
      Chris Lattner authored
      this code:
      
        store [stack slot #0],  R10
          = add R14, [stack slot #0]
      
      The spiller didn't know that the store made the value of [stackslot#0] available
      in R10 *IF* the store came from a copy instruction with the store folded into it.
      
      This patch teaches VirtRegMap to look at these stores and recognize the values
      they make available.  In one case Evan provided, this code:
      
              divsd %XMM0, %XMM1
              movsd %XMM1, QWORD PTR [%ESP + 40]
      1)      movsd QWORD PTR [%ESP + 48], %XMM1
      2)      movsd %XMM1, QWORD PTR [%ESP + 48]
              addsd %XMM1, %XMM0
      3)      movsd QWORD PTR [%ESP + 48], %XMM1
              movsd QWORD PTR [%ESP + 4], %XMM0
      
      turns into:
      
              divsd %XMM0, %XMM1
              movsd %XMM1, QWORD PTR [%ESP + 40]
              addsd %XMM1, %XMM0
      3)      movsd QWORD PTR [%ESP + 48], %XMM1
              movsd QWORD PTR [%ESP + 4], %XMM0
      
      In this case, instruction #2 was removed because of the value made
      available by #1, and inst #1 was later deleted because it is now
      never used before the stack slot is redefined by #3.
      
      This occurs here and there in a lot of code with high spilling, on PPC
      most of the removed loads/stores are LSU-reject-causing loads, which is
      nice.
      
      On X86, things are much better (because it spills more), where we nuke
      about 1% of the instructions from SMG2000 and several hundred from eon.
      
      More improvements to come...
      
      llvm-svn: 25917
      f3aef1b0
  2. Feb 02, 2006
  3. Feb 01, 2006
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