actually *removes* one of the operands, instead of just assigning both operands
the same register.  This make reasoning about instructions unnecessarily complex,
because you need to know if you are before or after register allocation to match
up operand #'s with the target description file.

Changing this also gets rid of a bunch of hacky code in various places.

This patch also includes changes to fold loads into cmp/test instructions in
the X86 backend, along with a significant simplification to the X86 spill
folding code.

llvm-svn: 30108

llvm-svn: 30099

llvm-svn: 30098

llvm-svn: 30066

llvm-svn: 30065

Restore it, which re-fixes X86/2006-08-21-ExtraMovInst.ll

llvm-svn: 30050

method for joining the live ranges instead of the fully-general one.

llvm-svn: 30049

need recursion.

llvm-svn: 30015

analysis 16% on crafty.

Wrap long lines.

llvm-svn: 30012

crafty with and without it).  Removing it speeds up live intervals 6%.

llvm-svn: 30010

llvm-svn: 29996

llvm-svn: 29995

llvm-svn: 29994

llvm-svn: 29989

number of copies, potentially defining live ranges that appear to have
differing value numbers that become identical when coallsced.  Among other
things, this fixes CodeGen/X86/shift-coalesce.ll and PR687.

llvm-svn: 29968

llvm-svn: 29921

llvm-svn: 29910

llvm-svn: 29896

paves the way for future changes, increases coallescing opportunities (in
theory, not witnessed in practice), and eliminates the really expensive
LiveIntervals::overlapsAliases method.

llvm-svn: 29890

instructions which define each value#) to simplify and improve the coallescer.
In particular, this patch:

1. Implements iterative coallescing.
2. Reverts an unsafe hack from handlePhysRegDef, superceeding it with a
   better solution.
3. Implements PR865, "coallescing" away the second copy in code like:

   A = B
   ...
   B = A

This also includes changes to symbolically print registers in intervals
when possible.

llvm-svn: 29862

defines each value# tracked by the interval.  This will be used to improve
coallescing.

llvm-svn: 29830

llvm-svn: 29805

*** Register mapping ***
  reg 1024 -> %reg1028
  reg 1026 -> EAX
  reg 1027 -> %reg1028

instead of:

*** Register mapping ***
  reg 1024 -> reg 1028
  reg 1026 -> reg 15
  reg 1027 -> reg 1028

llvm-svn: 29803

llvm-svn: 29250

llvm-svn: 29220

by Anton Korobeynikov!  This is a step towards closing PR786.

llvm-svn: 28447

llvm-svn: 28236

spilled.

llvm-svn: 28220

llvm-svn: 28197

llvm-svn: 28102

llvm-svn: 28039

But this is incorrect if the spilled value live range extends beyond the
current BB.
It is currently controlled by a temporary option -spiller-check-liveout.

llvm-svn: 28024

llvm-svn: 25515

llvm-svn: 25173

GDB use tolerable

llvm-svn: 25064

llvm-svn: 24019

For example, we can now join things like [0-30:0)[31-40:1)[52-59:2)
with [40:60:0) if the 52-59 range is defined by a copy from the 40-60 range.
The resultant range ends up being [0-30:0)[31-60:1).

This fires a lot through-out the test suite (e.g. shrinking bc from
19492 -> 18509 machineinstrs) though most gains are smaller (e.g. about
50 copies eliminated from crafty).

llvm-svn: 23866

llvm-svn: 23400

llvm-svn: 23294

only add a reload live range once for the instruction.  This is one step
towards fixing a regalloc pessimization that Nate notice, but is later undone
by the spiller (so no code is changed).

llvm-svn: 23293