For example:
bar() {
  int a = A[i];
  int b = A[i+1];
  B[i] = a;
  B[i+1] = b;
  foo(a);  <--- a is used outside the vectorized expression.
}

llvm-svn: 181648

llvm-svn: 181647

The shift amount may be larger than the type leading to undefined behavior.
Limit the transform to constant shift amounts. While there update the bits to
clear in the result which may enable additional optimizations.

PR15959.

llvm-svn: 181604

PR15952.

llvm-svn: 181586

llvm-svn: 181551

  iteration.
  
  This on step toward non-iterative GVN. My local hack suggests that getting rid
of iteration will speedup GVN by 30%+ on a medium sized input (2k LOC, C++).
I cannot explain why not 2x or more at this moment.

llvm-svn: 181532

When we replace an internal alias with its target, be careful not to
replace the entry in llvm.used (and llvm.compiler_used).

llvm-svn: 181524

That's obviously wrong. Conservatively restrict it to the sign bit, which
matches the original intention of this analysis. Fixes PR15940.

llvm-svn: 181518

A computable loop exit count does not imply the presence of an induction
variable. Scalar evolution can return a value for an infinite loop.

Fixes PR15926.

llvm-svn: 181495

- requires existing debug information to be present
- fixes up file name and line number information in metadata
- emits a "<orig_filename>-debug.ll" succinct IR file (without !dbg metadata
  or debug intrinsics) that can be read by a debugger
- initialize pass in opt tool to enable the "-debug-ir" flag
- lit tests to follow

llvm-svn: 181467

by switching to a ValueMap. Patch by Andrea DiBiagio!

llvm-svn: 181397

The two nested loops were confusing and also conservative in identifying
reduction variables. This patch replaces them by a worklist based approach.

llvm-svn: 181369

We were passing an i32 to ConstantInt::get where an i64 was needed and we must
also pass the sign if we pass negatives numbers. The start index passed to
getConsecutiveVector must also be signed.

Should fix PR15882.

llvm-svn: 181286

llvm-svn: 181249

Test case by Michele Scandale!

Fixes PR10293: Load not hoisted out of loop with multiple exits.

There are few regressions with this patch, now tracked by
rdar:13817079, and a roughly equal number of improvements. The
regressions are almost certainly back luck because LoopRotate has very
little idea of whether rotation is profitable. Doing better requires a
more comprehensive solution.

This checkin is a quick fix that lacks generality (PR10293 has
a counter-example). But it trivially fixes the case in PR10293 without
interfering with other cases, and it does satify the criteria that
LoopRotate is a loop canonicalization pass that should avoid
heuristics and special cases.

I can think of two approaches that would probably be better in
the long run. Ultimately they may both make sense.

(1) LoopRotate should check that the current header would make a good
loop guard, and that the loop does not already has a sufficient
guard. The artifical SimplifiedLoopLatch check would be unnecessary,
and the design would be more general and canonical. Two difficulties:

- We need a strong guarantee that we won't endlessly rotate, so the
  analysis would need to be precise in order to avoid the
  SimplifiedLoopLatch precondition.

- Analysis like this are usually based on SCEV, which we don't want to
  rely on.

(2) Rotate on-demand in late loop passes. This could even be done by
shoving the loop back on the queue after the optimization that needs
it. This could work well when we find LICM opportunities in
multi-branch loops. This requires some work, and it doesn't really
solve the problem of SCEV wanting a loop guard before the analysis.

llvm-svn: 181230

A * (1 - (uitofp i1 C)) -> select C, 0, A
B * (uitofp i1 C) -> select C, B, 0
select C, 0, A + select C, B, 0 -> select C, B, A

These come up in code that has been hand-optimized from a select to a linear blend, 
on platforms where that may have mattered. We want to undo such changes 
with the following transform:
A*(1 - uitofp i1 C) + B*(uitofp i1 C) -> select C, A, B

llvm-svn: 181216

llvm-svn: 181178

Thanks Nick Lewycky for pointing this out.

llvm-svn: 181177

We used to disable constant merging not only if a constant is llvm.used, but
also if an alias of a constant is llvm.used. This change fixes that.

llvm-svn: 181175

llvm-svn: 181157

Add support for min/max reductions when "no-nans-float-math" is enabled. This
allows us to assume we have ordered floating point math and treat ordered and
unordered predicates equally.

radar://13723044

llvm-svn: 181144

No need for setting the operands. The pointers are going to be bound by the
matcher.

radar://13723044

llvm-svn: 181142

We can just use the initial element that feeds the reduction.

  max(max(x, y), z) == max(max(x,y), max(x,z))

radar://13723044

llvm-svn: 181141

Patch by Robert Wilhelm.

llvm-svn: 181138

llvm-svn: 181082

Decompose GVN::processNonLocalLoad() (about 400 LOC) into smaller helper functions. No function change. 

This function consists of following steps:
   1. Collect dependent memory accesses.
   2. Analyze availability.
   3. Perform fully redundancy elimination, or 
   4. Perform PRE, depending on the availability

 Step 2, 3 and 4 are now moved to three helper routines.

llvm-svn: 181047

By supporting the vectorization of PHINodes with more than two incoming values we can increase the complexity of nested if statements.

We can now vectorize this loop:

int foo(int *A, int *B, int n) {
  for (int i=0; i < n; i++) {
    int x = 9;
    if (A[i] > B[i]) {
      if (A[i] > 19) {
        x = 3;
      } else if (B[i] < 4 ) {
        x = 4;
      } else {
        x = 5;
      }
    }
    A[i] = x;
  }
}

llvm-svn: 181037

Actually it took me couple of hours trying to make sense of them and
only to find they are dead code.  I guess the original author used
"allSingleSucc" to indicate if there are any critial edge emanating
from some blocks, and tried to perform code motion (actually speculation)
in the presence of these critical edges; but later on he/she changed mind
and decided to perform edge-splitting first.

llvm-svn: 180951

the things, and renames it to CBindingWrapping.h.  I also moved 
CBindingWrapping.h into Support/.

This new file just contains the macros for defining different wrap/unwrap 
methods.

The calls to those macros, as well as any custom wrap/unwrap definitions 
(like for array of Values for example), are put into corresponding C++ 
headers.

Doing this required some #include surgery, since some .cpp files relied 
on the fact that including Wrap.h implicitly caused the inclusion of a 
bunch of other things.

This also now means that the C++ headers will include their corresponding 
C API headers; for example Value.h must include llvm-c/Core.h.  I think 
this is harmless, since the C API headers contain just external function 
declarations and some C types, so I don't believe there should be any 
nasty dependency issues here.

llvm-svn: 180881

SROA: Generate selects instead of shuffles when blending values because this is the cannonical form.
Shuffles are more difficult to lower and we usually don't touch them, while we do optimize selects more often.

llvm-svn: 180875

This reverts commit r180802

There's ongoing discussion about whether this is the right place to make
this transformation. Reverting for now while we figure it out.

llvm-svn: 180834

prevent this, capture the location before RI is freed.

llvm-svn: 180824

llvm-svn: 180806

Always fold a shuffle-of-shuffle into a single shuffle when there's only one
input vector in the first place. Continue to be more conservative when there's
multiple inputs.

rdar://13402653
PR15866

llvm-svn: 180802

llvm-svn: 180794

the inlined function has multiple returns.

rdar://problem/12415623

llvm-svn: 180793

Differences in bitwidth between X and Y could exist even if C1 and C2 have
the same Log2 representation.

llvm-svn: 180779

This fixes the optimization introduced in r179748 and reverted in r179750.

While the optimization was sound, it did not properly respect differences in
bit-width.

llvm-svn: 180777

This resurrects r179957, but adds code that makes sure we don't touch
atomic/volatile stores:

This transformation will transform a conditional store with a preceeding
uncondtional store to the same location:

 a[i] =
 may-alias with a[i] load
 if (cond)
   a[i] = Y

into an unconditional store.

 a[i] = X
 may-alias with a[i] load
 tmp = cond ? Y : X;
 a[i] = tmp

We assume that on average the cost of a mispredicted branch is going to be
higher than the cost of a second store to the same location, and that the
secondary benefits of creating a bigger basic block for other optimizations to
work on outway the potential case where the branch would be correctly predicted
and the cost of the executing the second store would be noticably reflected in
performance.

hmmer's execution time improves by 30% on an imac12,2 on ref data sets. With
this change we are on par with gcc's performance (gcc also performs this
transformation). There was a 1.2 % performance improvement on a ARM swift chip.
Other tests in the test-suite+external seem to be mostly uninfluenced in my
experiments:
This optimization was triggered on 41 tests such that the executable was
different before/after the patch. Only 1 out of the 40 tests (dealII) was
reproducable below 100% (by about .4%). Given that hmmer benefits so much I
believe this to be a fair trade off.

llvm-svn: 180731

llvm-svn: 180700