First teach instcombine that sign bit checks only demand the
sign bit, this allows simplify demanded bits to hack on
expressions better.
Second, teach instcombine that ashr is useless if only the
sign bit is demanded.
llvm-svn: 39880
transformation. Also, keep track of which end of the integer interval overflows
occur on. This fixes Transforms/InstCombine/2007-06-21-DivCompareMiscomp.ll
and rdar://5278853, a miscompilation of perl.
llvm-svn: 37692
This sinks the two stores in this example into a single store in cond_next. In this
case, it allows elimination of the load as well:
store double 0.000000e+00, double* @s.3060
%tmp3 = fcmp ogt double %tmp1, 5.000000e-01 ; <i1> [#uses=1]
br i1 %tmp3, label %cond_true, label %cond_next
cond_true: ; preds = %entry
store double 1.000000e+00, double* @s.3060
br label %cond_next
cond_next: ; preds = %entry, %cond_true
%tmp6 = load double* @s.3060 ; <double> [#uses=1]
This implements Transforms/InstCombine/store-merge.ll:test2
llvm-svn: 36040
define i32 @test(i32 %X) {
entry:
%Y = and i32 %X, 4 ; <i32> [#uses=1]
icmp eq i32 %Y, 0 ; <i1>:0 [#uses=1]
sext i1 %0 to i32 ; <i32>:1 [#uses=1]
ret i32 %1
}
by moving code out of commonIntCastTransforms into visitZExt. Simplify the
APInt gymnastics in it etc.
llvm-svn: 35885
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
2. Use APInt[] instead of "X & SignBit".
3. Clean up some codes.
4. Make the expression like "ShiftAmt = ShiftAmtC->getZExtValue()" safe.
llvm-svn: 35424
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
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
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
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
* 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
* 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.
llvm-svn: 35321
* 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.
llvm-svn: 35287
* Re-enable the APInt version of MaskedValueIsZero.
* APIntify the Comput{Un}SignedMinMaxValuesFromKnownBits functions
* APIntify visitICmpInst.
llvm-svn: 35270
* Fix some indentation and comments in InsertRangeTest
* Add an "IsSigned" parameter to AddWithOverflow and make it handle signed
additions. Also, APIntify this function so it works with any bitwidth.
* For the icmp pred ([us]div %X, C1), C2 transforms, exit early if the
div instruction's RHS is zero.
* Finally, for icmp pred (sdiv %X, C1), -C2, fix an off-by-one error. The
HiBound needs to be incremented in order to get the range test correct.
llvm-svn: 35247
1. Replace getSignedMinValue() with getSignBit() for better code readability.
2. Replace APIntOps::shl() with operator<<= for convenience.
3. Make APInt construction more effective.
llvm-svn: 35060
Provide an APIntified version of MaskedValueIsZero. This will (temporarily)
cause a "defined but not used" message from the compiler. It will be used
in the next patch in this series.
Patch by Sheng Zhou.
llvm-svn: 35019
Add a new ComputeMaskedBits function that is APIntified. We'll slowly
convert things over to use this version. When its all done, we'll remove
the existing version.
llvm-svn: 35018
the order that instcombine processed instructions in the testcase. The end
result is that instcombine finished with:
define i16 @test1(i16 %a) {
%tmp = zext i16 %a to i32 ; <i32> [#uses=2]
%tmp21 = lshr i32 %tmp, 8 ; <i32> [#uses=1]
%tmp5 = shl i32 %tmp, 8 ; <i32> [#uses=1]
%tmp.upgrd.32 = or i32 %tmp21, %tmp5 ; <i32> [#uses=1]
%tmp.upgrd.3 = trunc i32 %tmp.upgrd.32 to i16 ; <i16> [#uses=1]
ret i16 %tmp.upgrd.3
}
which can't get matched as a bswap.
This patch makes instcombine more sophisticated about removing truncating
casts, allowing it to turn this into:
define i16 @test2(i16 %a) {
%tmp211 = lshr i16 %a, 8
%tmp52 = shl i16 %a, 8
%tmp.upgrd.323 = or i16 %tmp211, %tmp52
ret i16 %tmp.upgrd.323
}
which then matches as bswap. This fixes bswap.ll and implements
InstCombine/cast2.ll:test[12]. This also implements cast elimination of
add/sub.
llvm-svn: 34870
a value from the worklist required scanning the entire worklist to remove all
entries. We now use a combination map+vector to prevent duplicates from
happening and prevent the scan. This speeds up instcombine on a large file
from the llvm-gcc bootstrap from 189.7s to 4.84s in a debug build and from
5.04s to 1.37s in a release build.
llvm-svn: 34848
Make the Module's dependent library use a std::vector instead of SetVector
adjust #includes in .cpp files because SetVector.h is no longer included.
llvm-svn: 33855
This feature is needed in order to support shifts of more than 255 bits
on large integer types. This changes the syntax for llvm assembly to
make shl, ashr and lshr instructions look like a binary operator:
shl i32 %X, 1
instead of
shl i32 %X, i8 1
Additionally, this should help a few passes perform additional optimizations.
llvm-svn: 33776
pessimization where instcombine can sink a load (good for code size) that
prevents an alloca from being promoted by mem2reg (bad for everything).
llvm-svn: 33771
This occurs in C++ code like:
#include <iostream>
#include <iterator>
int a[] = { 1, 2, 3, 4, 5 };
int main() {
using namespace std;
copy(a, a + sizeof(a)/sizeof(a[0]), ostream_iterator<int>(cout, "\n"));
return 0;
}
Before we would decide the loop trip count is:
sdiv (i32 sub (i32 ptrtoint (i32* getelementptr ([5 x i32]* @a, i32 0, i32 5) to i32), i32 ptrtoint ([5 x i32]* @a to i32)), i32 4)
Now we decide it is "5". Amazing.
This code will need to be refactored, but I'm doing that as a separate
commit.
llvm-svn: 33665
changes: (1) don't special case for i1 any more, (2) use the new
TargetData::getTypeSizeInBits method to ensure source and dest are the
same bit width.
llvm-svn: 33427
We only want to do this if the src and destination types have the same
bit width. This patch uses TargetData::getTypeSizeInBits() instead of
making a special case for integer types and avoiding the transform if
they don't match.
llvm-svn: 33414
This is the final patch for this PR. It implements some minor cleanup
in the use of IntegerType, to wit:
1. Type::getIntegerTypeMask -> IntegerType::getBitMask
2. Type::Int*Ty changed to IntegerType* from Type*
3. ConstantInt::getType() returns IntegerType* now, not Type*
This also fixes PR1120.
Patch by Sheng Zhou.
llvm-svn: 33370
transform. Change some variable names so it is clear what is source and
what is dest of the cast. Also, add an assert to ensure that the integer
to integer case is asserting if the bitwidths are different. This prevents
illegal casts from being formed and catches bitwidth bugs sooner.
llvm-svn: 33337
because TargetData::getTypeSize() returns the same for i1 and i8. This fix
is not right for the full generality of bitwise types, but it fixes the
regression.
llvm-svn: 33237
rename Type::getIntegralTypeMask to Type::getIntegerTypeMask.
This makes naming much more consistent. For example, there are now no longer any
instances of IntegerType that are not considered isInteger! :)
llvm-svn: 33225
Implement the arbitrary bit-width integer feature. The feature allows
integers of any bitwidth (up to 64) to be defined instead of just 1, 8,
16, 32, and 64 bit integers.
This change does several things:
1. Introduces a new Derived Type, IntegerType, to represent the number of
bits in an integer. The Type classes SubclassData field is used to
store the number of bits. This allows 2^23 bits in an integer type.
2. Removes the five integer Type::TypeID values for the 1, 8, 16, 32 and
64-bit integers. These are replaced with just IntegerType which is not
a primitive any more.
3. Adjust the rest of LLVM to account for this change.
Note that while this incremental change lays the foundation for arbitrary
bit-width integers, LLVM has not yet been converted to actually deal with
them in any significant way. Most optimization passes, for example, will
still only deal with the byte-width integer types. Future increments
will rectify this situation.
llvm-svn: 33113
recommended that getBoolValue be replaced with getZExtValue and that
get(bool) be replaced by get(const Type*, uint64_t). This implements
those changes.
llvm-svn: 33110
This patch converts getPrimitiveSize to getPrimitiveSizeInBits where it is
appropriate to do so (comparison of integer primitive types).
llvm-svn: 33012
David Greene