Instead of producing code like this:

Loop:
  X = phi 0, X2
  ...

  X2 = X + 1
  if (X != N-1) goto Loop

We now generate code that looks like this:

Loop:
  X = phi 0, X2
  ...

  X2 = X + 1
  if (X2 != N) goto Loop

This has two big advantages:
  1. The trip count of the loop is now explicit in the code, allowing
     the direct implementation of Loop::getTripCount()
  2. This reduces register pressure in the loop, and allows X and X2 to be
     put into the same register.

As a consequence of the second point, the code we generate for loops went
from:

.LBB2:  # no_exit.1
	...
        mov %EDI, %ESI
        inc %EDI
        cmp %ESI, 2
        mov %ESI, %EDI
        jne .LBB2 # PC rel: no_exit.1

To:

.LBB2:  # no_exit.1
	...
        inc %ESI
        cmp %ESI, 3
        jne .LBB2 # PC rel: no_exit.1

... which has two fewer moves, and uses one less register.

llvm-svn: 12961

llvm-svn: 12960

llvm-svn: 12958

llvm-svn: 12956

insert it once!

llvm-svn: 12955

The iterator is pointing at the next instruction which should not disappear
when doing the load/store replacement.

llvm-svn: 12954

llvm-svn: 12953

at the bottom of the loop instead of the top.  This reduces the number of
overlapping live ranges a lot, for example, eliminating a spill in an important
loop in 183.equake with linear scan.

I still need to make the exit comparison of the loop use the post-incremented
version of this variable, but this is an easy first step.

llvm-svn: 12952

This should unbreak the Sparc JIT again.

llvm-svn: 12949

functions and is not needed here.
Simplify the pointer type check per Chris's suggestions.

llvm-svn: 12945

that matches its return type.

llvm-svn: 12944

Sorry these didn't get in yesterday.

llvm-svn: 12942

llvm-svn: 12940

even when the "optimization" I added before is turned off.  It generates this
extremely pointless code:

test:
        fld QWORD PTR [%ESP + 4]
        mov %AL, 0
        test %AL, %AL
        fcmove %ST(0), %ST(0)
        ret

Good thing the optimizer will have removed this before code generation
anyway.  :)

llvm-svn: 12939

On x86, memory operations occur in-order, so these are just lowered into
volatile loads and stores.

llvm-svn: 12936

X86/2004-04-13-FPCMOV-Crash.llx

A more robust fix is to follow.

llvm-svn: 12935

test/Regression/Transforms/SCCP/calltest.ll

llvm-svn: 12921

llvm-svn: 12919

llvm-svn: 12917

llvm-svn: 12905

llvm-svn: 12903

Fix several bugs in the intrinsics:
  1. Make sure to copy the input registers before the instructions that use them
  2. Make sure to copy the value returned by 'in' out of EAX into the register
     it is supposed to be in.

This fixes assertions when using in/out and linear scan.

llvm-svn: 12896

llvm-svn: 12895

llvm-svn: 12894

llvm-svn: 12893

LoopSimplify was not updating dominator frontiers correctly in some cases.

llvm-svn: 12890

llvm-svn: 12888

This is fairly straight-forward, but was a real nightmare to get just
perfect.  aarg.  :)

llvm-svn: 12884

llvm-svn: 12874

llvm-svn: 12872

llvm-svn: 12871

llvm-svn: 12869

llvm-svn: 12866

execute other CallGraphSCCPasses after the inliner without crashing.

llvm-svn: 12861

SCC passes much more useful.  In particular, this should fix the incredibly
stupid missed inlining opportunities that the inliner suffered from.

llvm-svn: 12860

llvm-svn: 12859

llvm-svn: 12858

llvm-svn: 12857

llvm-svn: 12856

llvm-svn: 12855