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Author SHA1 Message Date
Eric Christopher e7af7bd8d0 Move variable into assert to avoid unused variable warning. 
llvm-svn: 190886
 2013-09-17 21:13:57 +00:00
Arnold Schwaighofer cae8735a54 Costmodel: Add support for horizontal vector reductions 
Upcoming SLP vectorization improvements will want to be able to estimate costs
of horizontal reductions. Add infrastructure to support this.

We model reductions as a series of (shufflevector,add) tuples ultimately
followed by an extractelement. For example, for an add-reduction of <4 x float>
we could generate the following sequence:

 (v0, v1, v2, v3)
   \   \  /  /
     \  \  /
       +  +

 (v0+v2, v1+v3, undef, undef)
    \      /
 ((v0+v2) + (v1+v3), undef, undef)

 %rdx.shuf = shufflevector <4 x float> %rdx, <4 x float> undef,
                           <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
 %bin.rdx = fadd <4 x float> %rdx, %rdx.shuf
 %rdx.shuf7 = shufflevector <4 x float> %bin.rdx, <4 x float> undef,
                          <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
 %bin.rdx8 = fadd <4 x float> %bin.rdx, %rdx.shuf7
 %r = extractelement <4 x float> %bin.rdx8, i32 0

This commit adds a cost model interface "getReductionCost(Opcode, Ty, Pairwise)"
that will allow clients to ask for the cost of such a reduction (as backends
might generate more efficient code than the cost of the individual instructions
summed up). This interface is excercised by the CostModel analysis pass which
looks for reduction patterns like the one above - starting at extractelements -
and if it sees a matching sequence will call the cost model interface.

We will also support a second form of pairwise reduction that is well supported
on common architectures (haddps, vpadd, faddp).

 (v0, v1, v2, v3)
  \   /    \  /
 (v0+v1, v2+v3, undef, undef)
    \     /
 ((v0+v1)+(v2+v3), undef, undef, undef)

  %rdx.shuf.0.0 = shufflevector <4 x float> %rdx, <4 x float> undef,
        <4 x i32> <i32 0, i32 2 , i32 undef, i32 undef>
  %rdx.shuf.0.1 = shufflevector <4 x float> %rdx, <4 x float> undef,
        <4 x i32> <i32 1, i32 3, i32 undef, i32 undef>
  %bin.rdx.0 = fadd <4 x float> %rdx.shuf.0.0, %rdx.shuf.0.1
  %rdx.shuf.1.0 = shufflevector <4 x float> %bin.rdx.0, <4 x float> undef,
        <4 x i32> <i32 0, i32 undef, i32 undef, i32 undef>
  %rdx.shuf.1.1 = shufflevector <4 x float> %bin.rdx.0, <4 x float> undef,
        <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
  %bin.rdx.1 = fadd <4 x float> %rdx.shuf.1.0, %rdx.shuf.1.1
  %r = extractelement <4 x float> %bin.rdx.1, i32 0

llvm-svn: 190876
 2013-09-17 18:06:50 +00:00
Craig Topper 2cd5ff8003 Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size. 
llvm-svn: 186098
 2013-07-11 16:22:38 +00:00
Craig Topper 37039640e3 Fix indentation. No functional change. 
llvm-svn: 186065
 2013-07-11 05:39:44 +00:00
Arnold Schwaighofer b977387112 CostModel: Add parameter to instruction cost to further classify operand values 
On certain architectures we can support efficient vectorized version of
instructions if the operand value is uniform (splat) or a constant scalar.
An example of this is a vector shift on x86.

We can efficiently support

for (i = 0 ; i < ; i += 4)
  w[0:3] = v[0:3] << <2, 2, 2, 2>

but not

for (i = 0; i < ; i += 4)
  w[0:3] = v[0:3] << x[0:3]

This patch adds a parameter to getArithmeticInstrCost to further qualify operand
values as uniform or uniform constant.

Targets can then choose to return a different cost for instructions with such
operand values.

A follow-up commit will test this feature on x86.

radar://13576547

llvm-svn: 178807
 2013-04-04 23:26:21 +00:00
Benjamin Kramer f7cfac7a14 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

llvm-svn: 176287
 2013-02-28 19:09:33 +00:00
Arnold Schwaighofer 7e2ca6e74e Cost model: Add check for reverse shuffles to CostModel analysis 
Check for reverse shuffles in the CostModel analysis pass and query
TargetTransform info accordingly. This allows us we can write test cases for
reverse shuffles.

radar://13171406

llvm-svn: 174932
 2013-02-12 02:40:37 +00:00
Arnold Schwaighofer 594fa2dc2b 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

llvm-svn: 174713
 2013-02-08 14:50:48 +00:00
Chandler Carruth d3e73556d6 Move TargetTransformInfo to live under the Analysis library. This no 
longer would violate any dependency layering and it is in fact an
analysis. =]

llvm-svn: 171686
 2013-01-07 03:08:10 +00:00
Chandler Carruth cf569a8cdf Switch the cost model analysis over to just the TTI interface. 
llvm-svn: 171619
 2013-01-05 10:09:33 +00:00
Chandler Carruth 9fb823bbd4 Move all of the header files which are involved in modelling the LLVM IR 
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

llvm-svn: 171366
 2013-01-02 11:36:10 +00:00
Nadav Rotem 99868e4f9d Update the docs of the cost model. 
llvm-svn: 171016
 2012-12-24 05:51:12 +00:00
Nadav Rotem ce5db0fa3f constify the cost API 
llvm-svn: 169172
 2012-12-03 22:47:12 +00:00
Chandler Carruth ed0881b2a6 Use the new script to sort the includes of every file under lib. 
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
 2012-12-03 16:50:05 +00:00
Nadav Rotem 13da94734c CostModel: add support for Vector Insert and Extract. 
llvm-svn: 167329
 2012-11-02 22:31:56 +00:00
Nadav Rotem a6b91ac307 Add a cost model analysis that allows us to estimate the cost of IR-level instructions. 
llvm-svn: 167324
 2012-11-02 21:48:17 +00:00