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

a far more logical place.  Other methods should also be moved if anyone
is interested. :)

llvm-svn: 25912

llvm-svn: 25911

llvm-svn: 25910

llvm-svn: 25909

llvm-svn: 25908

llvm-svn: 25907

llvm-svn: 25906

llvm-svn: 25905

llvm-svn: 25903

llvm-svn: 25902

and instruction.  This allows us to compile stuff like this:

bool %X(int %X) {
        %Y = add int %X, 14
        %Z = setne int %Y, 12345
        ret bool %Z
}

to this:

_X:
        cmpl $12331, 4(%esp)
        setne %al
        movzbl %al, %eax
        ret

instead of this:

_X:
        cmpl $12331, 4(%esp)
        setne %al
        movzbl %al, %eax
        andl $1, %eax
        ret

This occurs quite a bit with the X86 backend.  For example, 25 times in
lambda, 30 times in 177.mesa, 14 times in galgel,  70 times in fma3d,
25 times in vpr, several hundred times in gcc, ~45 times in crafty,
~60 times in parser, ~140 times in eon, 110 times in perlbmk, 55 on gap,
16 times on bzip2, 14 times on twolf, and 1-2 times in many other SPEC2K
programs.

llvm-svn: 25901

llvm-svn: 25900

llvm-svn: 25899

(C1-X) == C2 --> X == C1-C2
(X+C1) == C2 --> X == C2-C1

This allows us to compile this:

bool %X(int %X) {
        %Y = add int %X, 14
        %Z = setne int %Y, 12345
        ret bool %Z
}

into this:

_X:
        cmpl $12331, 4(%esp)
        setne %al
        movzbl %al, %eax
        andl $1, %eax
        ret

not this:

_X:
        movl $14, %eax
        addl 4(%esp), %eax
        cmpl $12345, %eax
        setne %al
        movzbl %al, %eax
        andl $1, %eax
        ret

Testcase here: Regression/CodeGen/X86/compare-add.ll

nukage of the and coming up next.

llvm-svn: 25898

llvm-svn: 25897

llvm-svn: 25896

llvm-svn: 25895

llvm-svn: 25894

%C = call int asm "xyz $0, $1, $2, $3", "=r,r,r,0"(int %A, int %B, int 4)

and get:

xyz r2, r3, r4, r2

note that the r2's are pinned together.  Yaay for 2-address instructions.

2342 ----------------------------------------------------------------------

llvm-svn: 25893

llvm-svn: 25892

llvm-svn: 25891

llvm-svn: 25890

llvm-svn: 25889

llvm-svn: 25888

llvm-svn: 25887

substituted operands.  For this testcase:

int %test(int %A, int %B) {
  %C = call int asm "xyz $0, $1, $2", "=r,r,r"(int %A, int %B)
  ret int %C
}

we now emit:

_test:
        or r2, r3, r3
        or r3, r4, r4
        xyz r2, r2, r3  ;; look here
        or r3, r2, r2
        blr

... note the substituted operands. :)

llvm-svn: 25886

llvm-svn: 25885

llvm-svn: 25884

llvm-svn: 25883

llvm-svn: 25882

llvm-svn: 25881

llvm-svn: 25880

llvm-svn: 25879

int %test(int %A, int %B) {
  %C = call int asm "xyz $0, $1, $2", "=r,r,r"(int %A, int %B)
  ret int %C
}

into:

 (0x8906130, LLVM BB @0x8902220):
        %r2 = OR4 %r3, %r3
        %r3 = OR4 %r4, %r4
        INLINEASM <es:xyz $0, $1, $2>, %r2<def>, %r2, %r3
        %r3 = OR4 %r2, %r2
        BLR

which asmprints as:

_test:
        or r2, r3, r3
        or r3, r4, r4
        xyz $0, $1, $2      ;; need to print the operands now :)
        or r3, r2, r2
        blr

llvm-svn: 25878