Commit Graph

654 Commits

Author SHA1 Message Date
Nadav Rotem
b05130e1b2 Optimize sext <4 x i8> and <4 x i16> to <4 x i64>.
Patch by Ahmad, Muhammad T <muhammad.t.ahmad@intel.com>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177421 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-19 18:38:27 +00:00
Renato Golin
5ad5f5931e Improve long vector sext/zext lowering on ARM
The ARM backend currently has poor codegen for long sext/zext
operations, such as v8i8 -> v8i32. This patch addresses this
by performing a custom expansion in ARMISelLowering. It also
adds/changes the cost of such lowering in ARMTTI.

This partially addresses PR14867.

Patch by Pete Couperus

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177380 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-19 08:15:38 +00:00
Arnold Schwaighofer
bf37bf9e21 ARM cost model: Make some vector integer to float casts cheaper
The default logic marks them as too expensive.

For example, before this patch we estimated:
  cost of 16 for instruction:   %r = uitofp <4 x i16> %v0 to <4 x float>

While this translates to:
  vmovl.u16 q8, d16
  vcvt.f32.u32  q8, q8

All other costs are left to the values assigned by the fallback logic. Theses
costs are mostly reasonable in the sense that they get progressively more
expensive as the instruction sequences emitted get longer.

radar://13445992

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177334 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-18 22:47:09 +00:00
Arnold Schwaighofer
01f2571014 ARM cost model: Correct cost for some cheap float to integer conversions
Fix cost of some "cheap" cast instructions. Before this patch we used to
estimate for example:
  cost of 16 for instruction:   %r = fptoui <4 x float> %v0 to <4 x i16>

While we would emit:
  vcvt.s32.f32  q8, q8
  vmovn.i32 d16, q8
  vuzp.8  d16, d17

All other costs are left to the values assigned by the fallback logic. Theses
costs are mostly reasonable in the sense that they get progressively more
expensive as the instruction sequences emitted get longer.

radar://13434072

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177333 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-18 22:47:06 +00:00
Arnold Schwaighofer
5193e4ebe2 ARM cost model: Fix costs for some vector selects
I was too pessimistic in r177105. Vector selects that fit into a legal register
type lower just fine. I was mislead by the code fragment that I was using. The
stores/loads that I saw in those cases came from lowering the conditional off
an address.

Changing the code fragment to:

%T0_3 = type <8 x i18>
%T1_3 = type <8 x i1>

define void @func_blend3(%T0_3* %loadaddr, %T0_3* %loadaddr2,
                         %T1_3* %blend, %T0_3* %storeaddr) {
  %v0 = load %T0_3* %loadaddr
  %v1 = load %T0_3* %loadaddr2
==> FROM:
  ;%c = load %T1_3* %blend
==> TO:
  %c = icmp slt %T0_3 %v0, %v1
==> USE:
  %r = select %T1_3 %c, %T0_3 %v0, %T0_3 %v1

  store %T0_3 %r, %T0_3* %storeaddr
  ret void
}

revealed this mistake.

radar://13403975

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177170 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-15 18:31:01 +00:00
Arnold Schwaighofer
c0d8dc0eb6 ARM cost model: Fix cost of fptrunc and fpext instructions
A vector fptrunc and fpext simply gets split into scalar instructions.

radar://13192358

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177159 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-15 15:10:47 +00:00
Arnold Schwaighofer
d81511f0a6 ARM cost model: Increase cost of some vector selects we do terrible on
By terrible I mean we store/load from the stack.

This matters on PAQp8 in _Z5trainPsS_ii (which is inlined into Mixer::update)
where we decide to vectorize a loop with a VF of 8 resulting in a 25%
degradation on a cortex-a8.

LV: Found an estimated cost of 2 for VF 8 For instruction:   icmp slt i32
LV: Found an estimated cost of 2 for VF 8 For instruction:   select i1, i32, i32

The bug that tracks the CodeGen part is PR14868.

radar://13403975

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177105 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-14 19:17:02 +00:00
Arnold Schwaighofer
b6f4872d29 ARM cost model: Increase the cost for vector casts that use the stack
Increase the cost of v8/v16-i8 to v8/v16-i32 casts and truncates as the backend
currently lowers those using stack accesses.

This was responsible for a significant degradation on
MultiSource/Benchmarks/Trimaran/enc-pc1/enc-pc1
where we vectorize one loop to a vector factor of 16. After this patch we select
a vector factor of 4 which will generate reasonable code.

unsigned char cle[32];

void test(short c) {
  unsigned short compte;
  for (compte = 0; compte <= 31; compte++) {
    cle[compte] = cle[compte] ^ c;
  }
}

radar://13220512

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176898 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-12 21:19:22 +00:00
Jan Wen Voung
4323665bd8 Revert the test moves from 176733. Use "REQUIRES: asserts" instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176873 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-12 16:27:52 +00:00
Jan Wen Voung
fa785cb22d Disable statistics on Release builds and move tests that depend on -stats.
Summary:
Statistics are still available in Release+Asserts (any +Asserts builds),
and stats can also be turned on with LLVM_ENABLE_STATS.

Move some of the FastISel stats that were moved under DEBUG()
back out of DEBUG(), since stats are disabled across the board now.

Many tests depend on grepping "-stats" output.  Move those into
a orig_dir/Stats/. so that they can be marked as unsupported
when building without statistics.

Differential Revision: http://llvm-reviews.chandlerc.com/D486

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176733 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-08 22:56:31 +00:00
Shuxin Yang
985dac6579 Memory Dependence Analysis (not mem-dep test) take advantage of "invariant.load" metadata.
The "invariant.load" metadata indicates the memory unit being accessed is immutable.
A load annotated with this metadata can be moved across any store.

As I am not sure if it is legal to move such loads across barrier/fence, this
change dose not allow such transformation.

rdar://11311484

Thank Arnold for code review.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176562 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-06 17:48:48 +00:00
Arnold Schwaighofer
5f0d9dbdf4 X86 cost model: Adjust cost for custom lowered vector multiplies
This matters for example in following matrix multiply:

int **mmult(int rows, int cols, int **m1, int **m2, int **m3) {
  int i, j, k, val;
  for (i=0; i<rows; i++) {
    for (j=0; j<cols; j++) {
      val = 0;
      for (k=0; k<cols; k++) {
        val += m1[i][k] * m2[k][j];
      }
      m3[i][j] = val;
    }
  }
  return(m3);
}

Taken from the test-suite benchmark Shootout.

We estimate the cost of the multiply to be 2 while we generate 9 instructions
for it and end up being quite a bit slower than the scalar version (48% on my
machine).

Also, properly differentiate between avx1 and avx2. On avx-1 we still split the
vector into 2 128bits and handle the subvector muls like above with 9
instructions.
Only on avx-2 will we have a cost of 9 for v4i64.

I changed the test case in test/Transforms/LoopVectorize/X86/avx1.ll to use an
add instead of a mul because with a mul we now no longer vectorize. I did
verify that the mul would be indeed more expensive when vectorized with 3
kernels:

for (i ...)
   r += a[i] * 3;
for (i ...)
  m1[i] = m1[i] * 3; // This matches the test case in avx1.ll
and a matrix multiply.

In each case the vectorized version was considerably slower.

radar://13304919

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176403 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-02 04:02:52 +00:00
Benjamin Kramer
8611d4449a Cost model support for lowered math builtins.
We make the cost for calling libm functions extremely high as emitting the
calls is expensive and causes spills (on x86) so performance suffers. We still
vectorize important calls like ceilf and friends on SSE4.1. and fabs.

Differential Revision: http://llvm-reviews.chandlerc.com/D466

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176287 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-28 19:09:33 +00:00
Bill Wendling
351b7a10e2 Use references to attribute groups on the call/invoke instructions.
Listing all of the attributes for the callee of a call/invoke instruction is way
too much and makes the IR unreadable. Use references to attributes instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175877 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-22 09:09:42 +00:00
Elena Demikhovsky
52981c4b60 I optimized the following patterns:
sext <4 x i1> to <4 x i64>
 sext <4 x i8> to <4 x i64>
 sext <4 x i16> to <4 x i64>
 
I'm running Combine on SIGN_EXTEND_IN_REG and revert SEXT patterns:
 (sext_in_reg (v4i64 anyext (v4i32 x )), ExtraVT) -> (v4i64 sext (v4i32 sext_in_reg (v4i32 x , ExtraVT)))
 
 The sext_in_reg (v4i32 x) may be lowered to shl+sar operations.
 The "sar" does not exist on 64-bit operation, so lowering sext_in_reg (v4i64 x) has no vector solution.

I also added a cost of this operations to the AVX costs table.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175619 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-20 12:42:54 +00:00
Bill Wendling
7ab6c76ad1 Modify the LLVM assembly output so that it uses references to represent function attributes.
This makes the LLVM assembly look better. E.g.:

     define void @foo() #0 { ret void }
     attributes #0 = { nounwind noinline ssp }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175605 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-20 07:21:42 +00:00
Tim Northover
f13a7e2b21 AArch64: adjust tests which rely on a default JIT
Profiling tests *do* need a JIT. They'll pass if a cross-compiler targetting
AArch64 by default has been built, but fail if a native AArch64 compiler has
been build. Therefore XFAIL is inappropriate and we mark them unsupported.

ExecutionEngine tests are JIT by definition, they should also be unsupported.

Transforms/LICM only uses the interpreter to check the output is still sane
after optimisation. It can be switched to use an interpreter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175433 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-18 11:08:37 +00:00
Arnold Schwaighofer
6851623c54 ARM cost model: Add vector reverse shuffle costs
A reverse shuffle is lowered to a vrev and possibly a vext instruction (quad
word).

radar://13171406

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174933 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-12 02:40:39 +00:00
Bill Schmidt
0f58dbae4a Refine fix to bug 15041.
Thanks to help from Nadav and Hal, I have a more reasonable (and even
correct!) approach.  This specifically penalizes the insertelement
and extractelement operations for the performance hit that will occur
on PowerPC processors.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174725 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-08 18:19:17 +00:00
Arnold Schwaighofer
fb55a8fd7c ARM cost model: Address computation in vector mem ops not free
Adds a function to target transform info to query for the cost of address
computation. The cost model analysis pass now also queries this interface.
The code in LoopVectorize adds the cost of address computation as part of the
memory instruction cost calculation. Only there, we know whether the instruction
will be scalarized or not.
Increase the penality for inserting in to D registers on swift. This becomes
necessary because we now always assume that address computation has a cost and
three is a closer value to the architecture.

radar://13097204

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174713 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-08 14:50:48 +00:00
Arnold Schwaighofer
66f535a273 ARM cost model: Add costs for vector selects
Vector selects are cheap on NEON. They get lowered to a vbsl instruction.

radar://13158753

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174631 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-07 16:10:15 +00:00
Arnold Schwaighofer
e2d5590c33 ARM cost model: Cost for scalar integer casts and floating point conversions
Also adds some costs for vector integer float conversions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174371 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-05 14:05:55 +00:00
Arnold Schwaighofer
a7ad84851b ARM cost model: Penalize insertelement into D subregisters
Swift has a renaming dependency if we load into D subregisters. We don't have a
way of distinguishing between insertelement operations of values from loads and
other values. Therefore, we are pessimistic for now (The performance problem
showed up in example 14 of gcc-loops).

radar://13096933

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174300 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-04 02:52:05 +00:00
Hal Finkel
a8b289b70d Initial implementation of PPCTargetTransformInfo
This provides a place to add customized operation cost information and
control some other target-specific IR-level transformations.

The only non-trivial logic in this checkin assigns a higher cost to
unaligned loads and stores (covered by the included test case).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173520 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-25 23:05:59 +00:00
Nadav Rotem
b338d897f9 Make opt grab the triple from the module and use it to initialize the target machine.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171341 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-01 08:00:32 +00:00
Dmitri Gribenko
a6542923b8 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171250 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-30 02:33:22 +00:00
Dmitri Gribenko
a51edf0986 Add a check to the test Analysis/ScalarEvolution/2010-09-03-RequiredTransitive.ll
This test did not test anything at all (except for opt crashing, but that was
not the reason why it was added).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171248 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-30 01:42:34 +00:00
Dmitri Gribenko
b4912b9dcc Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171246 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-30 01:28:40 +00:00
Nadav Rotem
f85ec865f0 We are not ready to estimate the cost of integer expansions based on the number of parts. This test is too noisy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170999 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-23 09:11:07 +00:00
Nadav Rotem
f5637c3997 Improve the X86 cost model for loads and stores.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170830 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-21 01:33:59 +00:00
Jakub Staszak
270bfbd3d1 Reverse order of checking SSE level when calculating compare cost, so we check
AVX2 before AVX.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170464 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-18 22:57:56 +00:00
Arnold Schwaighofer
2b475922e6 Optimistically analyse Phi cycles
Analyse Phis under the starting assumption that they are NoAlias. Recursively
look at their inputs.
If they MayAlias/MustAlias there must be an input that makes them so.

Addresses bug 14351.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169788 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 23:02:41 +00:00
Nadav Rotem
0602bb4659 Cost Model: change the default cost of control flow instructions (br / ret / ...) to zero.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169423 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-05 21:21:26 +00:00
Preston Briggs
a4eff77e37 Modified dump() to provide a little
more information for dependences between
instructions that don't share a common loop.

Updated the test results appropriately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168965 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 00:44:47 +00:00
Preston Briggs
3c1cc3888b Modified depends() to recognize that when all levels are "=" and
there's no possible loo-independent dependence, then there's no
dependence.

Updated all test result appropriately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168719 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 19:12:26 +00:00
Preston Briggs
6ee74f52e9 Modify depends(Src, Dst, PossiblyLoopIndependent).
If the Src and Dst are the same instruction,
no loop-independent dependence is possible,
so we force the PossiblyLoopIndependent flag to false.

The test case results are updated appropriately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168678 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 06:41:46 +00:00
Preston Briggs
72a2c0622a Corrects a problem where we reply exclusively of GEPs to drive
analysis.  Better is to look for cases with useful GEPs and use them
when possible.  When a pair of useful GEPs is not available, use the
raw SCEVs directly. This approach supports better analysis of pointer
dereferencing.

In parallel, all the test cases are updated appropriately.
Cases where we have a store to *B++ can now be analyzed!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168474 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-21 23:50:04 +00:00
Hal Finkel
c37f502d48 Phi speculation improvement for BasicAA
This is a partial solution to PR14351. It removes some of the special
significance of the first incoming phi value in the phi aliasing checking logic
in BasicAA. In the context of a loop, the old logic assumes that the first
incoming value is the interesting one (meaning that it is the one that comes
from outside the loop), but this is often not the case.  With this change, we
now test first the incoming value that comes from a block other than the parent
of the phi being tested.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168245 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-17 02:33:15 +00:00
Benjamin Kramer
563e8fce2e DependenceAnalysis: Print all dependency pairs when dumping. Update all testcases.
Part of a patch by Preston Briggs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167827 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 12:12:02 +00:00
Nadav Rotem
a6fb97a49a CostModel: add another known vector trunc optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167488 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-06 21:17:17 +00:00
Nadav Rotem
b042868c01 Cost Model: add tables for some avx type-conversion hacks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167480 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-06 19:33:53 +00:00
Nadav Rotem
7ae3bcca45 CostModel: Add tables for the common x86 compares.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167421 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 23:48:20 +00:00
Nadav Rotem
2d1528b358 Code Model: Improve the accuracy of the zext/sext/trunc vector cost estimation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167412 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 22:20:53 +00:00
Nadav Rotem
a4ab5290e6 Cost Model: Normalize the insert/extract index when splitting types
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167402 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 21:12:13 +00:00
Nadav Rotem
75138f58b0 Cost Model: teach the cost model about expanding integers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167401 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 21:11:10 +00:00
Nadav Rotem
e623702c22 Implement the cost of abnormal x86 instruction lowering as a table.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167395 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 19:32:46 +00:00
Richard Osborne
544533301e Don't infer whether a value is captured in the current function from the
'nocapture' attribute.

The nocapture attribute only specifies that no copies are made that
outlive the function. This isn't the same as there being no copies at all.
This fixes PR14045.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167381 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 10:48:24 +00:00
Nadav Rotem
b4b04c3fa0 X86 CostModel: Add support for a some of the common arithmetic instructions for SSE4, AVX and AVX2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167347 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-03 00:39:56 +00:00
Nadav Rotem
0c31e43ff3 Add a stub for the x86 cost model impl. Implement a basic cost rule for inserting/extracting from XMM registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167333 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-02 23:27:16 +00:00
Nadav Rotem
f149567160 CostModel: add support for Vector Insert and Extract.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167329 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-02 22:31:56 +00:00
Nadav Rotem
6bed58ef24 Add a cost model analysis that allows us to estimate the cost of IR-level instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167324 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-02 21:48:17 +00:00
Benjamin Kramer
b8b3f6081f Remove LoopDependenceAnalysis.
It was unmaintained and not much more than a stub. The new DependenceAnalysis
pass is both more general and complete.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166810 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-26 20:25:01 +00:00
Sebastian Pop
ad43499fc4 dependence analysis
Patch from Preston Briggs <preston.briggs@gmail.com>.

This is an updated version of the dependence-analysis patch, including an MIV
test based on Banerjee's inequalities.

It's a fairly complete implementation of the paper

    Practical Dependence Testing
    Gina Goff, Ken Kennedy, and Chau-Wen Tseng
    PLDI 1991

It cannot yet propagate constraints between coupled RDIV subscripts (discussed
in Section 5.3.2 of the paper).

It's organized as a FunctionPass with a single entry point that supports testing
for dependence between two instructions in a function. If there's no dependence,
it returns null. If there's a dependence, it returns a pointer to a Dependence
which can be queried about details (what kind of dependence, is it loop
independent, direction and distance vector entries, etc). I haven't included
every imaginable feature, but there's a good selection that should be adequate
for supporting many loop transformations. Of course, it can be extended as
necessary.

Included in the patch file are many test cases, commented with C code showing
the loops and array references.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165708 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-11 07:32:34 +00:00
James Molloy
9e36496eb3 Add default JIT LIT variable.
Patch by David Tweed!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164996 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-02 10:57:08 +00:00
Duncan Sands
44401b7c80 Now that invoke of an intrinsic is possible (for the llvm.do.nothing intrinsic)
teach the callgraph logic to not create callgraph edges to intrinsics for invoke
instructions; it already skips this for call instructions.  Fixes PR13903.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164707 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-26 17:16:01 +00:00
Arnold Schwaighofer
3d5f96ee1b BasicAA: Recognize cyclic NoAlias phis
Enhances basic alias analysis to recognize phis whose first incoming values are
NoAlias and whose other incoming values are just the phi node itself through
some amount of recursion.

Example: With this change basicaa reports that ptr_phi and ptr_phi2 do not alias
each other.

bb:
 ptr = ptr2 + 1

loop:
  ptr_phi = phi [bb, ptr], [loop, ptr_plus_one]
  ptr2_phi = phi [bb, ptr2], [loop, ptr2_plus_one]
  ...
  ptr_plus_one = gep ptr_phi, 1
  ptr2_plus_one = gep ptr2_phi, 1

This enables the elimination of one load in code like the following:

extern int foo;

int test_noalias(int *ptr, int num, int* coeff) {
  int *ptr2 = ptr;
  int result = (*ptr++) * (*coeff--);
  while (num--) {
    *ptr2++ = *ptr;
    result +=  (*coeff--) * (*ptr++);
  }
  *ptr = foo;
  return result;
}

Part 2/2 of fix for PR13564.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163319 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:41:53 +00:00
Arnold Schwaighofer
029032693f BasicAA: GEPs of NoAlias'ing base ptr with equivalent indices are NoAlias
If we can show that the base pointers of two GEPs don't alias each other using
precise analysis and the indices and base offset are equal then the two GEPs
also don't alias each other.
This is primarily needed for the follow up patch that analyses NoAlias'ing PHI
nodes.

Part 1/2 of fix for PR13564.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163317 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:31:51 +00:00
NAKAMURA Takumi
c3c237d8be llvm/test/Analysis/Profiling: Mark 3 of them as REQUIRES: loadable_module.
FIXME: profile_rt.dll could be built on win32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162811 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-29 00:37:46 +00:00
Manman Ren
d26200423e Profile: set branch weight metadata with data generated from profiling.
This patch implements ProfileDataLoader which loads profile data generated by
-insert-edge-profiling and updates branch weight metadata accordingly.

Patch by Alastair Murray.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162799 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 22:21:25 +00:00
Manman Ren
1a710fdde1 BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle
the case of multiple edges from one block to another.

A simple example is a switch statement with multiple values to the same
destination. The definition of an edge is modified from a pair of blocks to
a pair of PredBlock and an index into the successors.

Also set the weight correctly when building SelectionDAG from LLVM IR,
especially when converting a Switch.
IntegersSubsetMapping is updated to calculate the weight for each cluster.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162572 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-24 18:14:27 +00:00
Benjamin Kramer
4e81d40545 Fix broken check lines.
I really need to find a way to automate this, but I can't come up with a regex
that has no false positives while handling tricky cases like custom check
prefixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162097 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 12:28:26 +00:00
Nadav Rotem
8dff60e96a MemoryDependenceAnalysis attempts to find the first memory dependency for function calls.
Currently, if GetLocation reports that it did not find a valid pointer (this is the case for volatile load/stores),
we ignore the result. This patch adds code to handle the cases where we did not obtain a valid pointer.

rdar://11872864  PR12899



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161802 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-13 23:03:43 +00:00
Nick Lewycky
6ce2471806 Stay rational; don't assert trying to take the square root of a negative value.
If it's negative, the loop is already proven to be infinite. Fixes PR13489!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161107 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-01 09:14:36 +00:00
Chandler Carruth
1de43ede89 Fix the remaining TCL-style quotes found in the testsuite. This is
another mechanical change accomplished though the power of terrible Perl
scripts.

I have manually switched some "s to 's to make escaping simpler.

While I started this to fix tests that aren't run in all configurations,
the massive number of tests is due to a really frustrating fragility of
our testing infrastructure: things like 'grep -v', 'not grep', and
'expected failures' can mask broken tests all too easily.

Essentially, I'm deeply disturbed that I can change the testsuite so
radically without causing any change in results for most platforms. =/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159547 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-02 19:09:46 +00:00
Chandler Carruth
49589f0d0e Convert the uses of '|&' to use '2>&1 |' instead, which works on old
versions of Bash. In addition, I can back out the change to the lit
built-in shell test runner to support this.

This should fix the majority of fallout on Darwin, but I suspect there
will be a few straggling issues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159544 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-02 18:37:59 +00:00
Chandler Carruth
4177e6fff5 Convert all tests using TCL-style quoting to use shell-style quoting.
This was done through the aid of a terrible Perl creation. I will not
paste any of the horrors here. Suffice to say, it require multiple
staged rounds of replacements, state carried between, and a few
nested-construct-parsing hacks that I'm not proud of. It happens, by
luck, to be able to deal with all the TCL-quoting patterns in evidence
in the LLVM test suite.

If anyone is maintaining large out-of-tree test trees, feel free to poke
me and I'll send you the steps I used to convert things, as well as
answer any painful questions etc. IRC works best for this type of thing
I find.

Once converted, switch the LLVM lit config to use ShTests the same as
Clang. In addition to being able to delete large amounts of Python code
from 'lit', this will also simplify the entire test suite and some of
lit's architecture.

Finally, the test suite runs 33% faster on Linux now. ;]
For my 16-hardware-thread (2x 4-core xeon e5520): 36s -> 24s

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159525 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-02 12:47:22 +00:00
Nick Lewycky
4d3bba5be4 If the step value is a constant zero, the loop isn't going to terminate. Fixes
the assert reported in PR13228!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159393 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-28 23:44:57 +00:00
Andrew Trick
fe3516f9a5 SCEV: Handle a corner case reducing AddRecExpr * AddRecExpr
If integer overflow causes one of the terms to reach zero, that can
force the entire expression to zero.

Fixes PR12929: cast<Ty>() argument of incompatible type

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157673 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-30 03:35:20 +00:00
Andrew Trick
8aa22019ca SCEV: Add MarkPendingLoopPredicates to avoid recursive isImpliedCond.
getUDivExpr attempts to simplify by checking for overflow.
isLoopEntryGuardedByCond then evaluates the loop predicate which
may lead to the same getUDivExpr causing endless recursion.

Fixes PR12868: clang 3.2 segmentation fault.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157092 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-19 00:48:25 +00:00
Bill Wendling
75920ad424 FileCheck-ize tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155434 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-24 10:45:44 +00:00
Bill Wendling
c6490d138f FileCheck-ize these tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155433 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-24 10:36:42 +00:00
Bill Wendling
d5cc8b81ca FileCheck-ize these tests. Harden some of them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155432 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-24 09:15:38 +00:00
Benjamin Kramer
86df062791 Revert "SCEV: When expanding a GEP the final addition to the base pointer has NUW but not NSW."
This isn't right either, reverting for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154910 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-17 06:33:57 +00:00
Benjamin Kramer
c77764591b SCEV: When expanding a GEP the final addition to the base pointer has NUW but not NSW.
Found by inspection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154262 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-07 17:19:26 +00:00
Rafael Espindola
8f3fabe0fe Handle intrinsics in GlobalsModRef. Fixes pr12351.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153604 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-28 21:31:24 +00:00
Andrew Trick
eb6dd23c95 SCEV fix: Handle loop invariant loads.
Fixes PR11882: NULL dereference in ComputeLoadConstantCompareExitLimit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153480 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-26 22:33:59 +00:00
Andrew Trick
54e3adea34 Test scalar evolution directly instead of testing the result of
canonical indvars.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153256 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-22 17:09:31 +00:00
Eli Friedman
cd38485b8a Duncan pointed out that if the alignment isn't explicitly specified, it defaults to the ABI alignment. Given that, make this code a bit more aggressive in such cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151584 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-27 23:16:46 +00:00
Eli Friedman
1680a24e53 Teach BasicAA about the LLVM IR rules that allow reading past the end of an object given sufficient alignment. Fixes PR12098.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151553 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-27 20:46:07 +00:00
Rafael Espindola
c9ae8cc24c Change the implementation of dominates(inst, inst) to one based on what the
verifier does. This correctly handles invoke.
Thanks to Duncan, Andrew and Chris for the comments.
Thanks to Joerg for the early testing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151469 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-26 02:19:19 +00:00
Eli Bendersky
0f0c411079 Replace all instances of dg.exp file with lit.local.cfg, since all tests are run with LIT now and now Dejagnu. dg.exp is no longer needed.
Patch reviewed by Daniel Dunbar. It will be followed by additional cleanup patches.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150664 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-16 06:28:33 +00:00
Nick Lewycky
b48a18903a Change CaptureTracking to pass a Use* instead of a Value* when a value is
captured. This allows the tracker to look at the specific use, which may be
especially interesting for function calls.

Use this to fix 'nocapture' deduction in FunctionAttrs. The existing one does
not iterate until a fixpoint and does not guarantee that it produces the same
result regardless of iteration order. The new implementation builds up a graph
of how arguments are passed from function to function, and uses a bottom-up walk
on the argument-SCCs to assign nocapture. This gets us nocapture more often, and
does so rather efficiently and independent of iteration order.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147327 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-28 23:24:21 +00:00
Chandler Carruth
51f40a725b Make the unreachable probability much much heavier. The previous
probability wouldn't be considered "hot" in some weird loop structures
or other compounding probability patterns. This makes it much harder to
confuse, but isn't really a principled fix. I'd actually like it if we
could model a zero probability, as it would make this much easier to
reason about. Suggestions for how to do this better are welcome.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147142 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-22 09:26:37 +00:00
Chandler Carruth
ddbc274169 Manually upgrade the test suite to specify the flag to cttz and ctlz.
I followed three heuristics for deciding whether to set 'true' or
'false':

- Everything target independent got 'true' as that is the expected
  common output of the GCC builtins.
- If the target arch only has one way of implementing this operation,
  set the flag in the way that exercises the most of codegen. For most
  architectures this is also the likely path from a GCC builtin, with
  'true' being set. It will (eventually) require lowering away that
  difference, and then lowering to the architecture's operation.
- Otherwise, set the flag differently dependending on which target
  operation should be tested.

Let me know if anyone has any issue with this pattern or would like
specific tests of another form. This should allow the x86 codegen to
just iteratively improve as I teach the backend how to differentiate
between the two forms, and everything else should remain exactly the
same.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146370 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-12 11:59:10 +00:00
Andrew Trick
ecb35ece5c SCEV fix. In general, Add/Mul expressions should not inherit NSW/NUW.
This reverts r139450, fixes r139453, and adds much needed comments and a
unit test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145367 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-29 02:16:38 +00:00
Andrew Trick
d2b5e2dd44 Filecheckize.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145363 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-29 02:05:23 +00:00
Chris Lattner
d2bf432b2b Upgrade syntax of tests using volatile instructions to use 'load volatile' instead of 'volatile load', which is archaic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145171 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-27 06:54:59 +00:00
Nick Lewycky
89d093d5b6 Don't forget to check FlagNW when determining whether an AddRecExpr will wrap
or not. Patch by Brendon Cahoon!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144173 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-09 07:11:37 +00:00
Benjamin Kramer
588d84c4df 2>&1 doesn't work here, it just creates an empty file called "&1"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143117 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-27 18:27:45 +00:00
Duncan Sands
f8a9eb1fa6 Restore commits 142790 and 142843 - they weren't breaking the build
bots.  Original commit messages:
- Reapply r142781 with fix. Original message:

  Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
  loop header when computing the trip count.

  With this, we now constant evaluate:
    struct ListNode { const struct ListNode *next; int i; };
    static const struct ListNode node1 = {0, 1};
    static const struct ListNode node2 = {&node1, 2};
    static const struct ListNode node3 = {&node2, 3};
    int test() {
      int sum = 0;
      for (const struct ListNode *n = &node3; n != 0; n = n->next)
        sum += n->i;
      return sum;
    }

- Now that we look at all the header PHIs, we need to consider all the header PHIs
  when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
  torture testsuite!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142919 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-25 12:28:52 +00:00
Chandler Carruth
45baf6bb85 Fix the API usage in loop probability heuristics. It was incorrectly
classifying many edges as exiting which were in fact not. These mainly
formed edges into sub-loops. It was also not correctly classifying all
returning edges out of loops as leaving the loop. With this match most
of the loop heuristics are more rational.

Several serious regressions on loop-intesive benchmarks like perlbench's
loop tests when built with -enable-block-placement are fixed by these
updated heuristics. Unfortunately they in turn uncover some other
regressions. There are still several improvemenst that should be made to
loop heuristics including trip-count, and early back-edge management.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142917 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-25 09:47:41 +00:00
Duncan Sands
526c80bae4 Speculatively revert commits 142790 and 142843 to see if it fixes
the dragonegg and llvm-gcc self-host buildbots.  Original commit
messages:
- Reapply r142781 with fix. Original message:

  Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
  loop header when computing the trip count.

  With this, we now constant evaluate:
    struct ListNode { const struct ListNode *next; int i; };
    static const struct ListNode node1 = {0, 1};
    static const struct ListNode node2 = {&node1, 2};
    static const struct ListNode node3 = {&node2, 3};
    int test() {
      int sum = 0;
      for (const struct ListNode *n = &node3; n != 0; n = n->next)
        sum += n->i;
      return sum;
    }

- Now that we look at all the header PHIs, we need to consider all the header PHIs
when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
torture testsuite!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142916 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-25 09:26:43 +00:00
Nick Lewycky
3846163aee Now that we look at all the header PHIs, we need to consider all the header PHIs
when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
torture testsuite!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142843 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 21:02:38 +00:00
Chandler Carruth
de1c9bb450 Remove return heuristics from the static branch probabilities, and
introduce no-return or unreachable heuristics.

The return heuristics from the Ball and Larus paper don't work well in
practice as they pessimize early return paths. The only good hitrate
return heuristics are those for:
 - NULL return
 - Constant return
 - negative integer return

Only the last of these three can possibly require significant code for
the returning block, and even the last is fairly rare and usually also
a constant. As a consequence, even for the cold return paths, there is
little code on that return path, and so little code density to be gained
by sinking it. The places where sinking these blocks is valuable (inner
loops) will already be weighted appropriately as the edge is a loop-exit
branch.

All of this aside, early returns are nearly as common as all three of
these return categories, and should actually be predicted as taken!
Rather than muddy the waters of the static predictions, just remain
silent on returns and let the CFG itself dictate any layout or other
issues.

However, the return heuristic was flagging one very important case:
unreachable. Unfortunately it still gave a 1/4 chance of the
branch-to-unreachable occuring. It also didn't do a rigorous job of
finding those blocks which post-dominate an unreachable block.

This patch builds a more powerful analysis that should flag all branches
to blocks known to then reach unreachable. It also has better worst-case
runtime complexity by not looping through successors for each block. The
previous code would perform an N^2 walk in the event of a single entry
block branching to N successors with a switch where each successor falls
through to the next and they finally fall through to a return.

Test case added for noreturn heuristics. Also doxygen comments improved
along the way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142793 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 12:01:08 +00:00
Nick Lewycky
7c3fc57472 Reapply r142781 with fix. Original message:
Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
  loop header when computing the trip count.

  With this, we now constant evaluate:
    struct ListNode { const struct ListNode *next; int i; };
    static const struct ListNode node1 = {0, 1};
    static const struct ListNode node2 = {&node1, 2};
    static const struct ListNode node3 = {&node2, 3};
    int test() {
      int sum = 0;
      for (const struct ListNode *n = &node3; n != 0; n = n->next)
        sum += n->i;
      return sum;
    }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142790 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 06:57:05 +00:00
Nick Lewycky
38af3d5a8d Speculatively revert r142781. Bots are showing
Assertion `i_nocapture < OperandTraits<PHINode>::operands(this) && "getOperand() out of range!"' failed.
coming out of indvars.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142786 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 04:00:25 +00:00
Nick Lewycky
795cb48f1a Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
loop header when computing the trip count.

With this, we now constant evaluate:
  struct ListNode { const struct ListNode *next; int i; };
  static const struct ListNode node1 = {0, 1};
  static const struct ListNode node2 = {&node1, 2};
  static const struct ListNode node3 = {&node2, 3};
  int test() {
    int sum = 0;
    for (const struct ListNode *n = &node3; n != 0; n = n->next)
      sum += n->i;
    return sum;
  }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142781 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-23 23:43:14 +00:00
Chandler Carruth
14edd314af Teach the BranchProbabilityInfo pass to print its results, and use that
to bring it under direct test instead of merely indirectly testing it in
the BlockFrequencyInfo pass.

The next step is to start adding tests for the various heuristics
employed, and to start fixing those heuristics once they're under test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142778 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-23 21:21:50 +00:00
Nick Lewycky
614fef6d5a Make SCEV's brute force analysis stronger in two ways. Firstly, we should be
able to constant fold load instructions where the argument is a constant.
Second, we should be able to watch multiple PHI nodes through the loop; this
patch only supports PHIs in loop headers, more can be done here.

With this patch, we now constant evaluate:
  static const int arr[] = {1, 2, 3, 4, 5};
  int test() {
    int sum = 0;
    for (int i = 0; i < 5; ++i) sum += arr[i];
    return sum;
  }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142731 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-22 19:58:20 +00:00
Chandler Carruth
941aa7b1e8 Generalize the reading of probability metadata to work for both branches
and switches, with arbitrary numbers of successors. Still optimized for
the common case of 2 successors for a conditional branch.

Add a test case for switch metadata showing up in the BlockFrequencyInfo pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142493 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-19 10:32:19 +00:00