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  1. Jun 29, 2012
  2. Jun 28, 2012
  3. Jun 26, 2012
    • Jakob Stoklund Olesen's avatar
      Allow targets to inject passes before the virtual register rewriter. · 59a0d324
      Jakob Stoklund Olesen authored
      Such passes can be used to tweak the register assignments in a
      target-dependent way, for example to avoid write-after-write
      dependencies.
      
      llvm-svn: 159209
      59a0d324
    • Chandler Carruth's avatar
      Update a bunch of stale comments that dated from when this folled the · 9139f44d
      Chandler Carruth authored
      very first (and worst) placement algorithm. These should now more
      accurately reflect the reality of the pass.
      
      llvm-svn: 159185
      9139f44d
    • Andrew Trick's avatar
      Enable the new LoopInfo algorithm by default. · fb2ba3e1
      Andrew Trick authored
      The primary advantage is that loop optimizations will be applied in a
      stable order. This helps debugging and unit test creation. It is also
      a better overall implementation without pathologically bad performance
      on deep functions.
      
      On large functions (llvm-stress --size=200000 | opt -loops)
      Before: 0.1263s
      After:  0.0225s
      
      On deep functions (after tweaking llvm-stress, thanks Nadav):
      Before: 0.2281s
      After:  0.0227s
      
      See r158790 for more comments.
      
      The loop tree is now consistently generated in forward order, but loop
      passes are applied in reverse order over the program. If we have a
      loop optimization that prefers forward order, that can easily be
      achieved by adding a different type of LoopPassManager.
      
      llvm-svn: 159183
      fb2ba3e1
    • Evan Cheng's avatar
      Make sure type is not extended or untyped before create a constant of the... · 4c6f917d
      Evan Cheng authored
      Make sure type is not extended or untyped before create a constant of the type. No test case. Found by inspection.
      
      llvm-svn: 159179
      4c6f917d
  4. Jun 25, 2012
    • Jakob Stoklund Olesen's avatar
      Enforce stricter liveness rules for PHIs. · a57fc12e
      Jakob Stoklund Olesen authored
      Verify that all paths from the entry block to a virtual register read
      pass through a def. Enable this check even when MRI->isSSA() is false.
      
      Verify that the live range of a virtual register is live out of all
      predecessor blocks, even for PHI-values.
      
      This requires that PHIElimination sometimes inserts IMPLICIT_DEF
      instruction in predecessor blocks.
      
      llvm-svn: 159150
      a57fc12e
    • Jakob Stoklund Olesen's avatar
      Run ProcessImplicitDefs on SSA form where it can be much simpler. · eb495664
      Jakob Stoklund Olesen authored
      Implicitly defined virtual registers can simply have the <undef> bit set
      on all uses, and copies can be turned into implicit defs recursively.
      
      Physical registers are a bit trickier. We handle the common case where a
      physreg def is used by a nearby instruction in the same basic block. For
      more complicated cases, just leave the IMPLICIT_DEF instruction in.
      
      llvm-svn: 159149
      eb495664
    • Jakob Stoklund Olesen's avatar
      Teach PHIElimination to handle <undef> operands. · 70ed924e
      Jakob Stoklund Olesen authored
      When a PHI use is <undef>, don't emit a copy in the predecessor block,
      but insert an IMPLICIT_DEF instruction instead. This ensures that
      virtual register uses are always jointly dominated by defs, even if some
      of them are IMPLICIT_DEF.
      
      llvm-svn: 159121
      70ed924e
    • Jakob Stoklund Olesen's avatar
      Handle <undef> operands in TwoAddressInstructionPass. · 6b556f82
      Jakob Stoklund Olesen authored
      When the source register to a 2-addr instruction is undefined, there is
      no need to attempt any transformations - simply replace the source
      register with the destination register.
      
      This also comes up when lowering IMPLICIT_DEF instructions - make sure
      the <undef> flag is moved to the new partial register def operand:
      
        %vreg8<def> = INSERT_SUBREG %vreg9<undef>, %vreg0<kill>, sub_16bit
      rewrite undef:
        %vreg8<def> = INSERT_SUBREG %vreg8<undef>, %vreg0<kill>, sub_16bit
      convert to:
        %vreg8:sub_16bit<def,read-undef> = COPY %vreg0<kill>
      
      llvm-svn: 159120
      6b556f82
  5. Jun 24, 2012
  6. Jun 23, 2012
  7. Jun 22, 2012
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