[test] Use -passes=instsimplify instead of -instsimplify in a number of tests. NFC

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

Differential Revision: htt

[test] Use -passes=instsimplify instead of -instsimplify in a number of tests. NFC

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

Differential Revision: https://reviews.llvm.org/D119080

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[InstSimplify] (-1 << x) s>> x --> -1

This was noticed in:
https://llvm.org/PR51351

https://alive2.llvm.org/ce/z/aLxunD

[InstSimplify] add tests for (-1 << x) s>> x; NFC

[InstSimplify] Add more poison folding optimizations

This adds more poison folding optimizations to InstSimplify.

Since all binary operators propagate poison, these are fine.

Also, the preconditio

[InstSimplify] Add more poison folding optimizations

This adds more poison folding optimizations to InstSimplify.

Since all binary operators propagate poison, these are fine.

Also, the precondition of `select cond, undef, x` -> `x` is relaxed to allow the case when `x` is undef.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D104661

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[InstSimplify] Fold out-of-bounds shift to poison

Make InstSimplify return poison rather than undef for out-of-bounds
shifts, as specified by LandRef:

> If op2 is (statically or dynamically) equal

[InstSimplify] Fold out-of-bounds shift to poison

Make InstSimplify return poison rather than undef for out-of-bounds
shifts, as specified by LandRef:

> If op2 is (statically or dynamically) equal to or larger than the
> number of bits in op1, this instruction returns a poison value.

Differential Revision: https://reviews.llvm.org/D93998

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[InstSimplify] Add tests that fold instructions with poison operands (NFC)

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

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

[InstSimplify] fold extracting from std::pair (1/2)

This patch intends to enable jump threading when a method whose return type is std::pair<int, bool> or std::pair<bool, int> is inlined.
For exampl

[InstSimplify] fold extracting from std::pair (1/2)

This patch intends to enable jump threading when a method whose return type is std::pair<int, bool> or std::pair<bool, int> is inlined.
For example, jump threading does not happen for the if statement in func.

std::pair<int, bool> callee(int v) {
int a = dummy(v);
if (a) return std::make_pair(dummy(v), true);
else return std::make_pair(v, v < 0);
}

int func(int v) {
std::pair<int, bool> rc = callee(v);
if (rc.second) {
// do something
}

SROA executed before the method inlining replaces std::pair by i64 without splitting in both callee and func since at this point no access to the individual fields is seen to SROA.
After inlining, jump threading fails to identify that the incoming value is a constant due to additional instructions (like or, and, trunc).

This series of patch add patterns in InstructionSimplify to fold extraction of members of std::pair. To help jump threading, actually we need to optimize the code sequence spanning multiple BBs.
These patches does not handle phi by itself, but these additional patterns help NewGVN pass, which calls instsimplify to check opportunities for simplifying instructions over phi, apply phi-of-ops optimization to result in successful jump threading.
SimplifyDemandedBits in InstCombine, can do more general optimization but this patch aims to provide opportunities for other optimizers by supporting a simple but common case in InstSimplify.

This first patch in the series handles code sequences that merges two values using shl and or and then extracts one value using lshr.

Differential Revision: https://reviews.llvm.org/D48828

llvm-svn: 338485

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[InstSimplify] tests for D48828, D49981: fold extraction from std::pair

Minor touch up in the previous comment.

llvm-svn: 338351

[InstSimplify] tests for D48828, D49981: fold extraction from std::pair

Updated unit tests for D48828 and D49981.

llvm-svn: 338350

[InstSimplify] tests for D48828: fold extraction from std::pair

This commit includes unit tests for D48828, which enhances InstSimplify to enable jump threading with a method whose return type is st

[InstSimplify] tests for D48828: fold extraction from std::pair

This commit includes unit tests for D48828, which enhances InstSimplify to enable jump threading with a method whose return type is std::pair<int, bool> or std::pair<bool, int>.
I am going to commit the actual transformation later.

llvm-svn: 338107

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[InstSimplify] fold shifts by sext bool

https://rise4fun.com/Alive/c3Y

llvm-svn: 335633

[InstSimplify] add tests for shifts by sext bool; NFC

llvm-svn: 335631

[PatternMatch] allow undef elements when matching a vector zero

This is the last step in getting constant pattern matchers to allow
undef elements in constant vectors.

I'm adding a dedicated m_Zero

[PatternMatch] allow undef elements when matching a vector zero

This is the last step in getting constant pattern matchers to allow
undef elements in constant vectors.

I'm adding a dedicated m_ZeroInt() function and building m_Zero() from
that. In most cases, calling code can be updated to use m_ZeroInt()
directly when there's no need to match pointers, but I'm leaving that
efficiency optimization as a follow-up step because it's not always
clear when that's ok.

There are just enough icmp folds in InstSimplify that can be used for
integer or pointer types, that we probably still want a generic m_Zero()
for those cases. Otherwise, we could eliminate it (and possibly add a
m_NullPtr() as an alias for isa<ConstantPointerNull>()).

We're conservatively returning a full zero vector (zeroinitializer) in
InstSimplify/InstCombine on some of these folds (see diffs in InstSimplify),
but I'm not sure if that's actually necessary in all cases. We may be
able to propagate an undef lane instead. One test where this happens is
marked with 'TODO'.


llvm-svn: 330550

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[InstSimplify, InstCombine] add vector tests with undef elts; NFC

llvm-svn: 330543

[InstSimplify] move tests for shifts; NFC

llvm-svn: 330516