llvm-svn: 21778

llvm-svn: 21776

in.  This tends to get cases like this:

  X = cast ubyte to int
  Y = shr int X, ...

Tested by: shift.ll:test24

llvm-svn: 21775

llvm-svn: 21772

llvm-svn: 21771

llvm-svn: 21770

of trying to do local reassociation tweaks at each level, only process an expression
tree once (at its root).  This does not improve the reassociation pass in any real way.

llvm-svn: 21768

    strlen(x) != 0 -> *x != 0
    strlen(x) == 0 -> *x == 0
* Change nested statistics to use style of other LLVM statistics so that
  only the name of the optimization (simplify-libcalls) is used as the
  statistic name, and the description indicates which specific all is
  optimized. Cuts down on some redundancy and saves a few bytes of space.
* Make note of stpcpy optimization that could be done.

llvm-svn: 21766

llvm-svn: 21762

Reassociate/shifttest.ll

llvm-svn: 21761

llvm-svn: 21759

llvm-svn: 21758

llvm-svn: 21752

llvm-svn: 21751

still to come.

llvm-svn: 21749

llvm-svn: 21748

llvm-svn: 21747

llvm-svn: 21746

llvm-svn: 21743

varargs munging code

llvm-svn: 21742

not change code after testing it without retesting!

llvm-svn: 21741

llvm-svn: 21740

llvm-svn: 21739

llvm-svn: 21738

llvm-svn: 21737

llvm-svn: 21736

llvm-svn: 21734

llvm-svn: 21729

llvm-svn: 21727

Alexander Friedman.

llvm-svn: 21722

llvm-svn: 21720

llvm-svn: 21719

llvm-svn: 21718

and.ll:test31

llvm-svn: 21717

the result, turn signed shift rights into unsigned shift rights if possible.

This leads to later simplification and happens *often* in 176.gcc.  For example,
this testcase:

struct xxx { unsigned int code : 8; };
enum codes { A, B, C, D, E, F };
int foo(struct xxx *P) {
  if ((enum codes)P->code == A)
     bar();
}

used to be compiled to:

int %foo(%struct.xxx* %P) {
        %tmp.1 = getelementptr %struct.xxx* %P, int 0, uint 0           ; <uint*> [#uses=1]
        %tmp.2 = load uint* %tmp.1              ; <uint> [#uses=1]
        %tmp.3 = cast uint %tmp.2 to int                ; <int> [#uses=1]
        %tmp.4 = shl int %tmp.3, ubyte 24               ; <int> [#uses=1]
        %tmp.5 = shr int %tmp.4, ubyte 24               ; <int> [#uses=1]
        %tmp.6 = cast int %tmp.5 to sbyte               ; <sbyte> [#uses=1]
        %tmp.8 = seteq sbyte %tmp.6, 0          ; <bool> [#uses=1]
        br bool %tmp.8, label %then, label %UnifiedReturnBlock

Now it is compiled to:

        %tmp.1 = getelementptr %struct.xxx* %P, int 0, uint 0           ; <uint*> [#uses=1]
        %tmp.2 = load uint* %tmp.1              ; <uint> [#uses=1]
        %tmp.2 = cast uint %tmp.2 to sbyte              ; <sbyte> [#uses=1]
        %tmp.8 = seteq sbyte %tmp.2, 0          ; <bool> [#uses=1]
        br bool %tmp.8, label %then, label %UnifiedReturnBlock

which is the difference between this:

foo:
        subl $4, %esp
        movl 8(%esp), %eax
        movl (%eax), %eax
        shll $24, %eax
        sarl $24, %eax
        testb %al, %al
        jne .LBBfoo_2

and this:

foo:
        subl $4, %esp
        movl 8(%esp), %eax
        movl (%eax), %eax
        testb %al, %al
        jne .LBBfoo_2

This occurs 3243 times total in the External tests, 215x in povray,
6x in each f2c'd program, 1451x in 176.gcc, 7x in crafty, 20x in perl,
25x in gap, 3x in m88ksim, 25x in ijpeg.

Maybe this will cause a little jump on gcc tommorow :)

llvm-svn: 21715

llvm-svn: 21713

llvm-svn: 21712

llvm-svn: 21709

* Remove commented-out debug printouts

llvm-svn: 21707

llvm-svn: 21706