[InstCombine] Infer zext nneg flag (#71534)

Use KnownBits to infer the nneg flag on zext instructions.

Currently we only set nneg when converting sext -> zext, but don't set
it when we have a ze

[InstCombine] Infer zext nneg flag (#71534)

Use KnownBits to infer the nneg flag on zext instructions.

Currently we only set nneg when converting sext -> zext, but don't set
it when we have a zext in the first place. If we want to use it in
optimizations, we should make sure the flag inference is consistent.

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[IR] Remove zext and sext constant expressions (#71040)

Remove support for zext and sext constant expressions. All places
creating them have been removed beforehand, so this just removes the
APIs

[IR] Remove zext and sext constant expressions (#71040)

Remove support for zext and sext constant expressions. All places
creating them have been removed beforehand, so this just removes the
APIs and uses of these constant expressions in tests.

There is some additional cleanup that can be done on top of this, e.g.
we can remove the ZExtInst vs ZExtOperator footgun.

This is part of
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.

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[test][InstCombine] Update some test cases to use opaque pointers

These tests cases were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34

Differential Re

[test][InstCombine] Update some test cases to use opaque pointers

These tests cases were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34

Differential Revision: https://reviews.llvm.org/D135094

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[InstCombine] avoid splitting a constant expression with div/rem fold

Follow-up to d4940c0f3d43 to further limit the transform
to avoid an unintended pattern/fold of a constant expression.

[InstCombine] fix miscompile from urem/udiv transform with constant expression

The isa<Constant> check could misfire on an instruction with 2 constant
operands. This bug was introduced with bb789381

[InstCombine] fix miscompile from urem/udiv transform with constant expression

The isa<Constant> check could misfire on an instruction with 2 constant
operands. This bug was introduced with bb789381fc11cce (D36988).

See issue #56810 for a C source example that exposed the bug.

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[InstCombine] add tests for udiv/urem miscompile; NFC

See issue #56810

[test] Use -passes=instcombine instead of -instcombine in lots of tests. NFC

Another step moving away from the deprecated syntax of specifying
pass pipeline in opt.

Differential Revision: https://r

[test] Use -passes=instcombine instead of -instcombine in lots of tests. NFC

Another step moving away from the deprecated syntax of specifying
pass pipeline in opt.

Differential Revision: https://reviews.llvm.org/D119081

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Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

[InstCombine] fix and enhance udiv/urem narrowing

There are 3 small independent changes here:

1. Account for multiple uses in the pattern matching: avoid the transform if it increases the instruc

[InstCombine] fix and enhance udiv/urem narrowing

There are 3 small independent changes here:

1. Account for multiple uses in the pattern matching: avoid the transform if it increases the instruction count.
2. Add a missing fold for the case where the numerator is the constant: http://rise4fun.com/Alive/E2p
3. Enable all folds for vector types.

There's still one more potential change - use "shouldChangeType()" to keep from transforming to an illegal integer type.

Differential Revision: https://reviews.llvm.org/D36988

llvm-svn: 311726

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[InstCombine] add udiv/urem tests with constant numerator; NFC

llvm-svn: 311396

[InstCombine] add more tests for udiv/urem narrowing; NFC

We don't currently limit these folds with hasOneUse() or shouldChangeType().

llvm-svn: 311390

[InstCombine] add vector tests; NFC

llvm-svn: 311339

[InstCombine] regenerate test checks; NFC

llvm-svn: 311337

Update Transforms tests to use CHECK-LABEL for easier debugging. No functionality change.

This update was done with the following bash script:

find test/Transforms -name "*.ll" | \
while read N

Update Transforms tests to use CHECK-LABEL for easier debugging. No functionality change.

This update was done with the following bash script:

find test/Transforms -name "*.ll" | \
while read NAME; do
echo "$NAME"
if ! grep -q "^; *RUN: *llc" $NAME; then
TEMP=`mktemp -t temp`
cp $NAME $TEMP
sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \
while read FUNC; do
sed -i '' "s/;\(.*\)\([A-Za-z0-9_]*\):\( *\)@$FUNC\([( ]*\)\$/;\1\2-LABEL:\3@$FUNC(/g" $TEMP
done
mv $TEMP $NAME
fi
done

llvm-svn: 186268

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InstCombine: Turn (zext A) udiv (zext B) into (zext (A udiv B)). Same for urem or constant B.

This obviously helps a lot if the division would be turned into a libcall
(think i64 udiv on i386), but

InstCombine: Turn (zext A) udiv (zext B) into (zext (A udiv B)). Same for urem or constant B.

This obviously helps a lot if the division would be turned into a libcall
(think i64 udiv on i386), but div is also one of the few remaining instructions
on modern CPUs that become more expensive when the bitwidth gets bigger.

This also helps register pressure on i386 when dividing chars, divb needs
two 8-bit parts of a 16 bit register as input where divl uses two registers.

int foo(unsigned char a) { return a/10; }
int bar(unsigned char a, unsigned char b) { return a/b; }

compiles into (x86_64)
_foo:
imull $205, %edi, %eax
shrl $11, %eax
ret
_bar:
movzbl %dil, %eax
divb %sil, %al
movzbl %al, %eax
ret

llvm-svn: 130615

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make instcombine only rewrite a chain of computation
(eliminating some extends) if the new type of the
computation is legal or if both the source and dest
are illegal. This prevents instcombine fro

make instcombine only rewrite a chain of computation
(eliminating some extends) if the new type of the
computation is legal or if both the source and dest
are illegal. This prevents instcombine from changing big
chains of computation into i64 on 32-bit targets for
example.

llvm-svn: 86398

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Change tests from "opt %s" to "opt < %s" so that opt doesn't see the
input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally ma

Change tests from "opt %s" to "opt < %s" so that opt doesn't see the
input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally match
strings in the input filename.

llvm-svn: 81537

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Use opt -S instead of piping bitcode output through llvm-dis.

llvm-svn: 81257

Change these tests to feed the assembly files to opt directly, instead
of using llvm-as, now that opt supports this.

llvm-svn: 81226

PR4548: optimize zext+udiv+trunc to udiv.

llvm-svn: 75539