store EAX -> [ss#0]
[ss#0] += 1
...
use(EAX)

In this case, it is not valid to rewrite this as:


store EAX -> [ss#0]
EAX += 1
store EAX -> [ss#0]  ;;; this would also delete the store above
...
use(EAX)

... because EAX is not a dead at that point.  Keep track of which registers
we are allowed to clobber, and which ones we aren't, and don't clobber the
ones we're not supposed to.  :)

This should resolve the issues on X86 last night.

llvm-svn: 25948

and PhysRegsAvailable maps out into a new AvailableSpills struct.  No
functionality change.

This paves the way for a bugfix, coming up next.

llvm-svn: 25947

llvm-svn: 25946

llvm-svn: 25945

llvm-svn: 25944

llvm-svn: 25943

llvm-svn: 25942

llvm-svn: 25941

llvm-svn: 25940

obsolete.  yaay :)

llvm-svn: 25939

instruction when possible.

llvm-svn: 25938

Remove the dead getRegClassForType method
minor formating changes.

llvm-svn: 25936

llvm-svn: 25935

llvm-svn: 25934

llvm-svn: 25932

llvm-svn: 25930

llvm-svn: 25929

llvm-svn: 25928

a std::multimap iterator value.  For some reason, GCC doesn't have a problem with this.

llvm-svn: 25927

llvm-svn: 25926

llvm-svn: 25925

llvm-svn: 25924

llvm-svn: 25923

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

llvm-svn: 25921

llvm-svn: 25920

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

llvm-svn: 25918

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

llvm-svn: 25916

llvm-svn: 25915

llvm-svn: 25914

Move isLoadFrom/StoreToStackSlot from MRegisterInfo to TargetInstrInfo,a far more logical place.  Other methods should also be moved if anyoneis interested. :)

llvm-svn: 25913

llvm-svn: 25911

llvm-svn: 25910

llvm-svn: 25908

llvm-svn: 25907

llvm-svn: 25906

llvm-svn: 25905

llvm-svn: 25903