stride. For a set of uses of the IV of a stride which is a multiple
of another stride, do not insert a new IV expression. Rather, reuse the
previous IV and rewrite the uses as uses of IV expression multiplied by
the factor.

e.g.
x = 0 ...; x ++
y = 0 ...; y += 4
then use of y can be rewritten as use of 4*x for x86.

llvm-svn: 26803

A*A*B + A*A*C   -->   A*(A*B+A*C)   -->   A*(A*(B+C))

This implements Reassociate/mul-factor3.ll

llvm-svn: 26757

llvm-svn: 26755

(x<<1)+(y<<1) -> (X+Y)<<1.  This implements
Transforms/Reassociate/shift-factor.ll

llvm-svn: 26753

transformation decisions.

llvm-svn: 26738

arrays out of range in a horrible way, but we shouldn't break it anyway.
Details in the comments.

llvm-svn: 26606

llvm-svn: 26580

the pointer is known to come from either a global variable, alloca or
malloc.  This allows us to compile this:

  P = malloc(28);
  memset(P, 0, 28);

into explicit stores on PPC instead of a memset call.

llvm-svn: 26577

Transforms/InstCombine/vec_narrow.ll.  This add support for narrowing
extract_element(insertelement) also.

llvm-svn: 26538

Testcase here: Transforms/Reassociate/mulfactor.ll

llvm-svn: 26524

This implements Transforms/InstCombine/add.ll:test31

llvm-svn: 26519

llvm-svn: 26484

pointed out: realize the AND can provide factors and look through Casts.

llvm-svn: 26469

Transforms/InstCombine/2006-02-28-Crash.ll

llvm-svn: 26427

llvm-svn: 26415

llvm-svn: 26413

llvm-svn: 26411

Make this code more powerful by using ComputeMaskedBits instead of looking
for an AND operand.  This lets us fold this:

int %test23(int %a) {
        %tmp.1 = and int %a, 1
        %tmp.2 = seteq int %tmp.1, 0
        %tmp.3 = cast bool %tmp.2 to int  ;; xor tmp1, 1
        ret int %tmp.3
}

into: xor (and a, 1), 1
llvm-svn: 26396

and  (A-B) == A  ->  B == 0

llvm-svn: 26394

InstCombine/or.ll:test23.

llvm-svn: 26385

in the code that does "select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y)))".
We now compile this loop:

LBB1_1: ; no_exit
        add r6, r2, r3
        subf r3, r2, r3
        cmpwi cr0, r2, 0
        addi r7, r5, 4
        lwz r2, 0(r5)
        addi r4, r4, 1
        blt cr0, LBB1_4 ; no_exit
LBB1_3: ; no_exit
        mr r3, r6
LBB1_4: ; no_exit
        cmpwi cr0, r4, 16
        mr r5, r7
        bne cr0, LBB1_1 ; no_exit

into this instead:

LBB1_1: ; no_exit
        srawi r6, r2, 31
        add r2, r2, r6
        xor r6, r2, r6
        addi r7, r5, 4
        lwz r2, 0(r5)
        addi r4, r4, 1
        add r3, r3, r6
        cmpwi cr0, r4, 16
        mr r5, r7
        bne cr0, LBB1_1 ; no_exit

llvm-svn: 26356

caused SPASS to fail building last night.

We can't trivially unswitch a loop if the exit block has phi nodes in it,
because we don't know which predecessor to use.

llvm-svn: 26320

to rewrite with the wrong value.

llvm-svn: 26311

llvm-svn: 26289

llvm-svn: 26287

llvm-svn: 26285

Thanks to nate for pointing this out :)

llvm-svn: 26280

llvm-svn: 26279

the right loop.

llvm-svn: 26277

llvm-svn: 26258

risk :)

llvm-svn: 26248

and ComputeMaskedBits to match the new improved versions in instcombine.
Tested against all of multisource/benchmarks on ppc.

llvm-svn: 26238

Change SplitBlock to increment a BasicBlock::iterator, not an Instruction*.  Apparently they do different things :)

This fixes a testcase that nate reduced from spass.

Also included are a couple minor code changes that don't affect the generated
code at all.

llvm-svn: 26235

llvm-svn: 26228

llvm-svn: 26225

unswitch this loop on 2 before sweating to unswitch on 1/3.

void test4(int N, int i, int C, int*P, int*Q) {
  int j;
  for (j = 0; j < N; ++j) {
    switch (C) {                // general unswitching.
    default: P[i+j] = 0; break;
    case 1: Q[i+j] = 0; break;
    case 3: P[i+j] = Q[i+j]; break;
    case 2: break;              //  TRIVIAL UNSWITCH on C==2
    }
  }
}

llvm-svn: 26223

this for example:

  for (j = 0; j < N; ++j) {     // trivial unswitch
    if (C)
      P[i+j] = 0;
  }

turning it into the obvious code without bothering to duplicate an empty loop.

llvm-svn: 26220

Y = seteq bool X, true
instead of just using X :)

llvm-svn: 26215

llvm-svn: 26194

llvm-svn: 26191