target hook.  This allows us to codegen a loop as:

LBB1_1: @cond_next
        mov r2, #0
        str r2, [r0, +r3, lsl #2]
        add r3, r3, #1
        cmn r3, #1
        bne LBB1_1      @cond_next

instead of:

LBB1_1: @cond_next
        mov r2, #0
        str r2, [r0], #+4
        add r3, r3, #1
        cmn r3, #1
        bne LBB1_1      @cond_next

This looks the same, but has one fewer induction variable (and therefore,
one fewer register) live in the loop.

llvm-svn: 35592

llvm-svn: 35588

llvm-svn: 35587

test/Transforms/InstCombine/xor.ll:test28

llvm-svn: 35584

isel has its own particular features that it wants in the CFG, in order to
reduce the number of times a constant is computed, etc.  Make sure that we
clean up the CFG before doing any other things for isel.  Doing so can
dramatically reduce the number of split edges and reduce the number of
places that constants get computed.  For example, this shrinks
CodeGen/Generic/phi-immediate-factoring.ll from 44 to 37 instructions on X86,
and from 21 to 17 MBB's in the output.  This is primarily a code size win,
not a performance win.

This implements CodeGen/Generic/phi-immediate-factoring.ll and PR1296.

llvm-svn: 35575

llvm-svn: 35563

llvm-svn: 35561

llvm-svn: 35555

Support overloaded intrinsics bswap, ctpop, cttz, ctlz.

llvm-svn: 35547

llvm-svn: 35536

llvm-svn: 35528

llvm-svn: 35525

llvm-svn: 35524

llvm-svn: 35510

   amount is safe.
2. Use new method on ConstantInt instead of (? :) operator.
3. Use new method uge() on ConstantInt to simplify codes.

llvm-svn: 35505

llvm-svn: 35503

2. Let APInt variable do the binary operation stuff instead of using
   ConstantExpr::getXXX.

llvm-svn: 35450

llvm-svn: 35446

1. Line out nested call of APInt::zext/trunc.
2. Make more use of APInt::getHighBitsSet/getLowBitsSet.
3. Use APInt[] operator instead of expression like "APIntVal & SignBit".

llvm-svn: 35444

   instead of using ConstantExpr::getXX.
2. Use constant reference to APInt if possible instead of expensive
   APInt copy.

llvm-svn: 35443

llvm-svn: 35431

2. Use APInt[] instead of "X & SignBit".
3. Clean up some codes.
4. Make the expression like "ShiftAmt = ShiftAmtC->getZExtValue()" safe.

llvm-svn: 35424

2. Make the APInt value do the zext/trunc stuff instead of using
   ConstantExpr::getZExt().

llvm-svn: 35422

llvm-svn: 35418

llvm-svn: 35414

1. Line out nested use of zext/trunc.
2. Make more use of getHighBitsSet/getLowBitsSet.
3. Use APInt[] != 0 instead of "(APInt & SignBit) != 0".

llvm-svn: 35408

When converting an add/xor/and triplet into a trunc/sext, only do so if the
intermediate integer type is a bitwidth that the targets can handle.

llvm-svn: 35400

llvm-svn: 35383

llvm-svn: 35373

Fix another incorrectly converted shift mask.

llvm-svn: 35371

llvm-svn: 35361

original and new instruction. A slight performance hit with ostringstream
but it is only for debug.
Also, clean up an uninitialized variable warning noticed in a release build.

llvm-svn: 35358

llvm-svn: 35357

Fix SingleSource/Regression/C/2003-05-21-UnionBitFields.c by changing a
getHighBitsSet call to getLowBitsSet call that was incorrectly converted
from the original lshr constant expression.

llvm-svn: 35348

llvm-svn: 35347

Remove a use of getLowBitsSet that caused the mask used for replacement of
shl/lshr pairs with an AND instruction to be computed incorrectly. Its not
clear exactly why this is the case. This solves the disappearing shifts
problem, but it doesn't fix Regression/C/2003-05-21-UnionBitFields. It
seems there is more going on.

llvm-svn: 35342

llvm-svn: 35341

* Don't assume shift amounts are <= 64 bits
* Avoid creating an extra APInt in SubOne and AddOne by using -- and ++
* Add another use of getLowBitsSet
* Convert a series of if statements to a switch

llvm-svn: 35339

using the facilities of APInt. While this duplicates a tiny fraction of
the constant folding code, it also makes the code easier to read and
avoids large ConstantExpr overhead for simple, known computations.

llvm-svn: 35335

2. Use isStrictlyPositive() instead of isPositive() in two places where
   they need APInt value > 0 not only >=0.

llvm-svn: 35333