[InstCombine] rename variable for easier reading; NFC

We usually give constants a 'C' somewhere in the name...

llvm-svn: 299474

[InstCombine] Turn subtract of vectors of i1 into xor like we do for scalar i1. Matches what we already do for add.

llvm-svn: 299472

[InstCombine] Fix typo last->least. NFC

llvm-svn: 299123

NFC. InstCombiner::visitFAdd extract LHSIntVal/RHSIntVal local variables

llvm-svn: 298359

[InstCombine] don't try SimplifyDemandedInstructionBits from add/sub because it's slow and unlikely to succeed

Notably, no regression tests change when we remove these calls, and these are expensive

[InstCombine] don't try SimplifyDemandedInstructionBits from add/sub because it's slow and unlikely to succeed

Notably, no regression tests change when we remove these calls, and these are expensive calls.

The motivation comes from the general acknowledgement that the compiler is getting slower:
http://lists.llvm.org/pipermail/llvm-dev/2017-January/109188.html
http://lists.llvm.org/pipermail/llvm-dev/2016-December/108279.html

And specifically the test case attached to PR32037:
https://bugs.llvm.org//show_bug.cgi?id=32037

Profiling the middle-end (opt) part of the compile:
$ ./opt -O2 row_common.bc -o /dev/null

...visitAdd and visitSub are near the top of the instcombine list, and the calls to SimplifyDemandedInstructionBits()
are high within each of those. Those calls account for 1%+ of the opt time in either debug or release profiles. And
that's the rough win I see from this patch when testing opt built release from r295864 on an iMac with Haswell 4GHz
(model 4790K).

It seems unlikely that we'd be able to eliminate add/sub or change their operands given that add/sub normally affect
all bits, and the PR32037 example shows no IR difference after this change using -O2.

Also worth noting - the code comment in visitAdd:
// This handles stuff like (X & 254)+1 -> (X&254)|1
...isn't true. That transform is handled later with a call to haveNoCommonBitsSet().

Differential Revision: https://reviews.llvm.org/D30270

llvm-svn: 295898

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[InstCombine] add nsw/nuw X, signbit --> or X, signbit

Changing to 'or' (rather than 'xor' when no wrapping flags are set)
allows icmp simplifies to happen as expected.

Differential Revision: https

[InstCombine] add nsw/nuw X, signbit --> or X, signbit

Changing to 'or' (rather than 'xor' when no wrapping flags are set)
allows icmp simplifies to happen as expected.

Differential Revision: https://reviews.llvm.org/D29729

llvm-svn: 295574

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[InstCombine] improve formatting; NFC

llvm-svn: 295237

[InstCombine] add a wrapper for a common pair of transforms; NFCI

Some of the callers are artificially limiting this transform to integer types;
this should make it easier to incrementally remove th

[InstCombine] add a wrapper for a common pair of transforms; NFCI

Some of the callers are artificially limiting this transform to integer types;
this should make it easier to incrementally remove that restriction.

llvm-svn: 291620

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[InstCombine] Combine adds across a zext

We can perform the following:
(add (zext (add nuw X, C1)), C2) -> (zext (add nuw X, C1+C2))

This is only possible if C2 is negative and C2 is greater than o

[InstCombine] Combine adds across a zext

We can perform the following:
(add (zext (add nuw X, C1)), C2) -> (zext (add nuw X, C1+C2))

This is only possible if C2 is negative and C2 is greater than or equal to negative C1.

llvm-svn: 290927

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[InstCombine] Address post-commit feedback

llvm-svn: 290741

[InstCombine] More thoroughly canonicalize the position of zexts

We correctly canonicalized (add (sext x), (sext y)) to (sext (add x, y))
where possible. However, we didn't perform the same canonic

[InstCombine] More thoroughly canonicalize the position of zexts

We correctly canonicalized (add (sext x), (sext y)) to (sext (add x, y))
where possible. However, we didn't perform the same canonicalization
for zexts or for muls.

llvm-svn: 290733

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Revert @llvm.assume with operator bundles (r289755-r289757)

This creates non-linear behavior in the inliner (see more details in
r289755's commit thread).

llvm-svn: 290086

Remove the AssumptionCache

After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is mo

Remove the AssumptionCache

After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is more computationally efficient, and also we need much less
code...

llvm-svn: 289756

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[InstCombine] use m_APInt to allow sub with constant folds for splat vectors

llvm-svn: 284247

[InstCombine] sub X, sext(bool Y) -> add X, zext(bool Y)

Prefer add/zext because they are better supported in terms of value-tracking.

Note that the backend should be prepared for this IR canonical

[InstCombine] sub X, sext(bool Y) -> add X, zext(bool Y)

Prefer add/zext because they are better supported in terms of value-tracking.

Note that the backend should be prepared for this IR canonicalization
(including vector types) after:
https://reviews.llvm.org/rL284015

Differential Revision: https://reviews.llvm.org/D25135

llvm-svn: 284241

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InstCombine: Replace some never-null pointers with references. NFC

llvm-svn: 277792

[InstCombine] fold add(zext(xor X, C), C) --> sext X when C is INT_MIN in the source type

The pattern may look more obviously like a sext if written as:

define i32 @g(i16 %x) {
%zext = zext i

[InstCombine] fold add(zext(xor X, C), C) --> sext X when C is INT_MIN in the source type

The pattern may look more obviously like a sext if written as:

define i32 @g(i16 %x) {
%zext = zext i16 %x to i32
%xor = xor i32 %zext, 32768
%add = add i32 %xor, -32768
ret i32 %add
}

We already have that fold in visitAdd().

Differential Revision: https://reviews.llvm.org/D22477

llvm-svn: 276035

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[InstCombine] allow X + signbit --> X ^ signbit for vector splats

llvm-svn: 275691

Apply clang-tidy's modernize-loop-convert to most of lib/Transforms.

Only minor manual fixes. No functionality change intended.

llvm-svn: 273808

Delete more dead code.

Found by gcc 6.

llvm-svn: 273402

Remove uses of builtin comma operator.

Cleanup for upcoming Clang warning -Wcomma. No functionality change intended.

llvm-svn: 261270

Fix Clang-tidy readability-redundant-control-flow warnings; other minor fixes.

Differential revision: http://reviews.llvm.org/D16793

llvm-svn: 259539

function names start with a lowercase letter; NFC

llvm-svn: 259425

[InstCombine] Fix indentation. NFC.

llvm-svn: 256131

Fix some Clang-tidy modernize warnings, other minor fixes.

Fixed warnings are: modernize-use-override, modernize-use-nullptr and modernize-redundant-void-arg.

Differential revision: http://reviews.

Fix some Clang-tidy modernize warnings, other minor fixes.

Fixed warnings are: modernize-use-override, modernize-use-nullptr and modernize-redundant-void-arg.

Differential revision: http://reviews.llvm.org/D14312

llvm-svn: 252087

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