some constant exprs to apints).
Thanks to Anton for tracking down a small testcase that triggered this!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35633 91177308-0d34-0410-b5e6-96231b3b80d8
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".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35408 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35348 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35342 91177308-0d34-0410-b5e6-96231b3b80d8
