Fixes http://llvm.org/PR16221, http://llvm.org/PR15927
Phabricator: http://llvm-reviews.chandlerc.com/D1236

Patch by Andrew Tulloch!

llvm-svn: 195016

[ASan] Fix PR17867 - make sure ASan doesn't crash if use-after-scope and use-after-return are combined.

llvm-svn: 195014

In some case the loop exit count computation can overflow. Extend the type to
prevent most of those cases.

The problem is loops like:
int main ()
{
  int a = 1;
  char b = 0;
  lbl:
    a &= 4;
    b--;
    if (b) goto lbl;
  return a;
}

The backedge count is 255. The induction variable type is i8. If we add one to
255 to get the exit count we overflow to zero.

To work around this issue we extend the type of the induction variable to i32 in
the case of i8 and i16.

PR17532

llvm-svn: 195008

Fixed an inappropriate use of BuildPairF64 when compiling for MIPS32 with FP64
which resulted in an impossible constraint on the register allocation. It now
uses BuildPairF64_64.

llvm-svn: 195007

Note that there's no hardware yet that relies on that encoding.

llvm-svn: 195006

    
The immediate field should be encoded as "imm - 1" as the CPU always adds one to that field.

llvm-svn: 195004

This change is incorrect. If you delete virtual destructor of both a base class
and a subclass, then the following code:
  Base *foo = new Child();
  delete foo;
will not cause the destructor for members of Child class. As a result, I observe
plently of memory leaks. Notable examples I investigated are:
ObjectBuffer and ObjectBufferStream, AttributeImpl and StringSAttributeImpl.

llvm-svn: 194997

Set some unspecified bits of INS/DUP to zero as ARMARM requested.

llvm-svn: 194996

The functions are like: vst1_s8_x2 ...

llvm-svn: 194990

Debug info verifier is part of the verifier which is a Function Pass.
Tot currently tries to pull all reachable debug info MDNodes in each function,
which is too time-consuming. The correct fix seems to be separating debug info
verification to its own module pass.

I will disable the debug info verifier until a correct fix is found.

For Bill's testing case, enabling debug info verifier increase compile
time from 11s to 11m.

llvm-svn: 194986

llvm-svn: 194985

llvm-svn: 194981

llvm-svn: 194980

llvm-svn: 194979

llvm-svn: 194975

We used to collect debug info MDNodes in doInitialization and verify them in
doFinalization. That is incorrect since MDNodes can be modified by passes run
between doInitialization and doFinalization.

To fix the problem, we handle debug info MDNodes that can be reached from a
function in runOnFunction (i.e we collect those nodes by calling processDeclare,
processValue and processLocation, and then verify them in runOnFunction).

We handle debug info MDNodes that can be reached from named metadata in
doFinalization. This is in line with how Verifier handles module-level data
(they are verified in doFinalization).

rdar://15472296

llvm-svn: 194974

We used to depend on running processModule before the other public functions
such as processDeclare, processValue and processLocation. We are now relaxing
the constraint by adding a module argument to the three functions and
letting the three functions to initialize the type map. This will be used in
a follow-on patch that collects nodes reachable from a Function.

llvm-svn: 194973

eraseFromParent() invalidates OldName.

llvm-svn: 194970

This adds a boolean member variable to the PassManagerBuilder to control loop
rerolling (just like we have for unrolling and the various vectorization
options). This is necessary for control by the frontend. Loop rerolling remains
disabled by default at all optimization levels.

llvm-svn: 194966

This reverts commit f1d9fe9d04ce93f6d5dcebbd2cb6a07414d7a029.

This was causing PR17964. We need to use thread data before regular data.

llvm-svn: 194960

llvm-svn: 194959

[block-freq] Add BlockFrequency::scale that returns a remainder from the division and make the private scale in BlockFrequency more performant.

This change is the first in a series of changes improving LLVM's Block
Frequency propogation implementation to not lose probability mass in
branchy code when propogating block frequency information from a basic
block to its successors. This patch is a simple infrastructure
improvement that does not actually modify the block frequency
algorithm. The specific changes are:

1. Changes the division algorithm used when scaling block frequencies by
branch probabilities to a short division algorithm. This gives us the
remainder for free as well as provides a nice speed boost. When I
benched the old routine and the new routine on a Sandy Bridge iMac with
disabled turbo mode performing 8192 iterations on an array of length
32768, I saw ~600% increase in speed in mean/median performance.

2. Exposes a scale method that returns a remainder. This is important so
we can ensure that when we scale a block frequency by some branch
probability BP = N/D, the remainder from the division by D can be
retrieved and propagated to other children to ensure no probability mass
is lost (more to come on this).

llvm-svn: 194950

llvm-svn: 194945

llvm-svn: 194944

Generally speaking, control flow paths with error reporting calls are cold.
So far, error reporting calls are calls to perror and calls to fprintf,
fwrite, etc. with stderr as the stream. This can be extended in the future.

The primary motivation is to improve block placement (the cold attribute
affects the static branch prediction heuristics).

llvm-svn: 194943

Implementing this on bigendian platforms could get strange. I added a
target hook, getStackSlotRange, per Jakob's recommendation to make
this as explicit as possible.

llvm-svn: 194942

llvm-svn: 194941

llvm-svn: 194940

This adds a loop rerolling pass: the opposite of (partial) loop unrolling. The
transformation aims to take loops like this:

for (int i = 0; i < 3200; i += 5) {
  a[i]     += alpha * b[i];
  a[i + 1] += alpha * b[i + 1];
  a[i + 2] += alpha * b[i + 2];
  a[i + 3] += alpha * b[i + 3];
  a[i + 4] += alpha * b[i + 4];
}

and turn them into this:

for (int i = 0; i < 3200; ++i) {
  a[i] += alpha * b[i];
}

and loops like this:

for (int i = 0; i < 500; ++i) {
  x[3*i] = foo(0);
  x[3*i+1] = foo(0);
  x[3*i+2] = foo(0);
}

and turn them into this:

for (int i = 0; i < 1500; ++i) {
  x[i] = foo(0);
}

There are two motivations for this transformation:

  1. Code-size reduction (especially relevant, obviously, when compiling for
code size).

  2. Providing greater choice to the loop vectorizer (and generic unroller) to
choose the unrolling factor (and a better ability to vectorize). The loop
vectorizer can take vector lengths and register pressure into account when
choosing an unrolling factor, for example, and a pre-unrolled loop limits that
choice. This is especially problematic if the manual unrolling was optimized
for a machine different from the current target.

The current implementation is limited to single basic-block loops only. The
rerolling recognition should work regardless of how the loop iterations are
intermixed within the loop body (subject to dependency and side-effect
constraints), but the significant restriction is that the order of the
instructions in each iteration must be identical. This seems sufficient to
capture all current use cases.

This pass is not currently enabled by default at any optimization level.

llvm-svn: 194939

llvm-svn: 194936

InstCombine, in visitFPTrunc, applies the following optimization to sqrt calls:

  (fptrunc (sqrt (fpext x))) -> (sqrtf x)

but does not apply the same optimization to llvm.sqrt. This is a problem
because, to enable vectorization, Clang generates llvm.sqrt instead of sqrt in
fast-math mode, and because this optimization is being applied to sqrt and not
applied to llvm.sqrt, sometimes the fast-math code is slower.

This change makes InstCombine apply this optimization to llvm.sqrt as well.

This fixes the specific problem in PR17758, although the same underlying issue
(optimizations applied to libcalls are not applied to intrinsics) exists for
other optimizations in SimplifyLibCalls.

llvm-svn: 194935

llvm-svn: 194934

llvm-svn: 194932

Fix ScalarEvolution bugs uncovered by this.

llvm-svn: 194928

llvm-svn: 194927

Per Rafael's review of r194514.

llvm-svn: 194926

This is common in bitfield code.

llvm-svn: 194925

No functionality change.

llvm-svn: 194917

llvm-svn: 194906

The tests just hit this with a different sized
address space since I haven't figured out how
to use this to break it.

I thought I committed this a long time ago,
and I'm not sure why missing this hasn't caused
any problems.

llvm-svn: 194903