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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35575 91177308-0d34-0410-b5e6-96231b3b80d8
amount is safe.
2. Use new method on ConstantInt instead of (? :) operator.
3. Use new method uge() on ConstantInt to simplify codes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35505 91177308-0d34-0410-b5e6-96231b3b80d8
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".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35444 91177308-0d34-0410-b5e6-96231b3b80d8
instead of using ConstantExpr::getXX.
2. Use constant reference to APInt if possible instead of expensive
APInt copy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35443 91177308-0d34-0410-b5e6-96231b3b80d8
2. Use APInt[] instead of "X & SignBit".
3. Clean up some codes.
4. Make the expression like "ShiftAmt = ShiftAmtC->getZExtValue()" safe.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35424 91177308-0d34-0410-b5e6-96231b3b80d8
1. Line out nested use of zext/trunc.
2. Make more use of getHighBitsSet/getLowBitsSet.
3. Use APInt[] != 0 instead of "(APInt & SignBit) != 0".
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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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35400 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35358 91177308-0d34-0410-b5e6-96231b3b80d8
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.
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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.
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* 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
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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.
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2. Use isStrictlyPositive() instead of isPositive() in two places where
they need APInt value > 0 not only >=0.
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* Convert the last use of a uint64_t that should have been an APInt.
* Change ComputeMaskedBits to have a const reference argument for the Mask
so that recursions don't cause unneeded temporaries. This causes temps
to be needed in other places (where the mask has to change) but this
change optimizes for the recursion which is more frequent.
* Remove two instances of &ing a Mask with getAllOnesValue. Its not
needed any more because APInt is accurate in its bit computations.
* Start using the getLowBitsSet and getHighBits set methods on APInt
instead of shifting. This makes it more clear in the code what is
going on.
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Convert some calls to ConstantInt::getZExtValue() into getValue() and
use APInt facilities in the subsequent computations.
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* APIntify visitAdd and visitSelectInst
* Remove unused uint64_t versions of utility functions that have been
replaced with APInt versions.
This completes most of the changes for APIntification of InstCombine. This
passes llvm-test and llvm/test/Transforms/InstCombine/APInt.
Patch by Zhou Sheng.
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