InstCombine: Correctly propagate NSW/NUW for x-(-A) -> x+A

We can only propagate the nsw bits if both subtraction instructions are
marked with the appropriate bit.

N.B. We only propagate the nsw b

InstCombine: Correctly propagate NSW/NUW for x-(-A) -> x+A

We can only propagate the nsw bits if both subtraction instructions are
marked with the appropriate bit.

N.B. We only propagate the nsw bit in InstCombine because the nuw case
is already handled in InstSimplify.

This fixes PR20189.

llvm-svn: 214385

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Fix Typo (first commit to test commit access)

llvm-svn: 213228

Make helper functions static.

llvm-svn: 212460

InstCombine: Don't turn -(x/INT_MIN) -> x/INT_MIN

It is not safe to negate the smallest signed integer, doing so yields
the same number back.

This fixes PR20186.

llvm-svn: 212164

Added instruction combine to transform few more negative values addition to subtraction (Part 3)
This patch enables transforms for

(x + (~(y | c) + 1) --> x - (y | c) if c is odd

Differential Revis

Added instruction combine to transform few more negative values addition to subtraction (Part 3)
This patch enables transforms for

(x + (~(y | c) + 1) --> x - (y | c) if c is odd

Differential Revision: http://reviews.llvm.org/D4210

llvm-svn: 211881

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This patch removed duplicate code for matching patterns
which are now handled in SimplifyUsingDistributiveLaws()
(after r211261)

Differential Revision: http://reviews.llvm.org/D4253

llvm-svn: 211

This patch removed duplicate code for matching patterns
which are now handled in SimplifyUsingDistributiveLaws()
(after r211261)

Differential Revision: http://reviews.llvm.org/D4253

llvm-svn: 211768

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Added instruction combine to transform few more negative values addition to subtraction (Part 2)
This patch enables transforms for

(x + (~(y | c) + 1) --> x - (y | c) if c is even

Differential

Added instruction combine to transform few more negative values addition to subtraction (Part 2)
This patch enables transforms for

(x + (~(y | c) + 1) --> x - (y | c) if c is even

Differential Revision: http://reviews.llvm.org/D4209

llvm-svn: 211765

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Added instruction combine to transform few more negative values addition to subtraction (Part 1)
This patch enables transforms for following patterns.
(x + (~(y & c) + 1) --> x - (y & c)
(x +

Added instruction combine to transform few more negative values addition to subtraction (Part 1)
This patch enables transforms for following patterns.
(x + (~(y & c) + 1) --> x - (y & c)
(x + (~((y >> z) & c) + 1) --> x - ((y>>z) & c)

Differential Revision: http://reviews.llvm.org/D3733

llvm-svn: 211266

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Refactored and updated SimplifyUsingDistributiveLaws() to
* Find factorization opportunities using identity values.
* Find factorization opportunities by treating shl(X, C) as mul (X, shl(C))
* K

Refactored and updated SimplifyUsingDistributiveLaws() to
* Find factorization opportunities using identity values.
* Find factorization opportunities by treating shl(X, C) as mul (X, shl(C))
* Keep NSW flag while simplifying instruction using factorization.

This fixes PR19263.

Differential Revision: http://reviews.llvm.org/D3799

llvm-svn: 211261

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[InstCombine] mark ADD with nuw if no unsigned overflow

Summary:
As a starting step, we only use one simple heuristic: if the sign bits
of both a and b are zero, we can prove "add a, b" do not unsig

[InstCombine] mark ADD with nuw if no unsigned overflow

Summary:
As a starting step, we only use one simple heuristic: if the sign bits
of both a and b are zero, we can prove "add a, b" do not unsigned
overflow, and thus convert it to "add nuw a, b".

Updated all affected tests and added two new tests (@zero_sign_bit and
@zero_sign_bit2) in AddOverflow.ll

Test Plan: make check-all

Reviewers: eliben, rafael, meheff, chandlerc

Reviewed By: chandlerc

Subscribers: chandlerc, llvm-commits

Differential Revision: http://reviews.llvm.org/D4144

llvm-svn: 211084

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InstCombine: Improvement to check if signed addition overflows.

This patch implements two things:

1. If we know one number is positive and another is negative, we return true as
signed addition

InstCombine: Improvement to check if signed addition overflows.

This patch implements two things:

1. If we know one number is positive and another is negative, we return true as
signed addition of two opposite signed numbers will never overflow.

2. Implemented TODO : If one of the operands only has one non-zero bit, and if
the other operand has a known-zero bit in a more significant place than it
(not including the sign bit) the ripple may go up to and fill the zero, but
won't change the sign. e.x - (x & ~4) + 1

We make sure that we are ignoring 0 at MSB.

Patch by Suyog Sarda.

llvm-svn: 210186

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Add back commit r210029.

The code was actually correct. Sorry for the confusion. I have expanded the
comment saying why the analysis is valid to avoid me misunderstaning it
again in the future.

llv

Add back commit r210029.

The code was actually correct. Sorry for the confusion. I have expanded the
comment saying why the analysis is valid to avoid me misunderstaning it
again in the future.

llvm-svn: 210052

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Revert "Add the nsw flag when we detect that an add will not signed overflow."

This reverts commit r210029.

It was not correctly handling cases where LHS and RHS had multiple but different
sign bit

Revert "Add the nsw flag when we detect that an add will not signed overflow."

This reverts commit r210029.

It was not correctly handling cases where LHS and RHS had multiple but different
sign bits.

llvm-svn: 210048

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Add the nsw flag when we detect that an add will not signed overflow.

We already had a function for checking this, we were just using it only in
specialized cases.

llvm-svn: 210029

Revert "Revert "Revert "InstCombine: Improvement to check if signed addition overflows."""

This reverts commit r209776.

It was miscompiling llvm::SelectionDAGISel::MorphNode.

llvm-svn: 209817

Revert "Revert "InstCombine: Improvement to check if signed addition overflows.""

This reverts commit r209762, bringing back r209746. It was not responsible for the libc++ build failure

llvm-svn: 2

Revert "Revert "InstCombine: Improvement to check if signed addition overflows.""

This reverts commit r209762, bringing back r209746. It was not responsible for the libc++ build failure

llvm-svn: 209776

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Revert "InstCombine: Improvement to check if signed addition overflows."

This reverts commit r209746.

It looks it is causing a crash while building libcxx. I am trying to get a
reduced testcase.

l

Revert "InstCombine: Improvement to check if signed addition overflows."

This reverts commit r209746.

It looks it is causing a crash while building libcxx. I am trying to get a
reduced testcase.

llvm-svn: 209762

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InstCombine: Improvement to check if signed addition overflows.

This patch implements two things:

1. If we know one number is positive and another is negative, we return true as
signed addition

InstCombine: Improvement to check if signed addition overflows.

This patch implements two things:

1. If we know one number is positive and another is negative, we return true as
signed addition of two opposite signed numbers will never overflow.

2. Implemented TODO : If one of the operands only has one non-zero bit, and if
the other operand has a known-zero bit in a more significant place than it
(not including the sign bit) the ripple may go up to and fill the zero, but
won't change the sign. e.x - (x & ~4) + 1

We make sure that we are ignoring 0 at MSB.

Patch by Suyog Sarda.

llvm-svn: 209746

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Rename ComputeMaskedBits to computeKnownBits. "Masked" has been
inappropriate since it lost its Mask parameter in r154011.

llvm-svn: 208811

Reorder shuffle and binary operation.

This patch enables transformations:

BinOp(shuffle(v1), shuffle(v2)) -> shuffle(BinOp(v1, v2))
BinOp(shuffle(v1), const1) -> shuffle(BinOp, const2)

The

Reorder shuffle and binary operation.

This patch enables transformations:

BinOp(shuffle(v1), shuffle(v2)) -> shuffle(BinOp(v1, v2))
BinOp(shuffle(v1), const1) -> shuffle(BinOp, const2)

They allow to eliminate extra shuffles in some cases.

Differential Revision: http://reviews.llvm.org/D3525

llvm-svn: 208488

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[C++] Use 'nullptr'. Transforms edition.

llvm-svn: 207196

[Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a co

[Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.

Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.

llvm-svn: 206844

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[Modules] Sink all the DEBUG_TYPE defines for InstCombine out of the
header files and into the cpp files.

These files will require more touches as the header files actually use
DEBUG(). Eventually,

[Modules] Sink all the DEBUG_TYPE defines for InstCombine out of the
header files and into the cpp files.

These files will require more touches as the header files actually use
DEBUG(). Eventually, I'll have to introduce a matched #define and #undef
of DEBUG_TYPE for the header files, but that comes as step N of many to
clean all of this up.

llvm-svn: 206777

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[Modules] Move the LLVM IR pattern match header into the IR library, it
obviously is coupled to the IR.

llvm-svn: 202818

[Modules] Move GetElementPtrTypeIterator into the IR library. As its
name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.

Another step o

[Modules] Move GetElementPtrTypeIterator into the IR library. As its
name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.

Another step of modularizing the support library.

llvm-svn: 202815

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