Commit Graph

171 Commits

Author SHA1 Message Date
Dmitri Gribenko d29ea04446 Fix a -Wdocumentation warning
llvm-svn: 179789
2013-04-18 20:13:04 +00:00
Arnold Schwaighofer 4cd6aa110c LoopVectorizer: Recognize min/max reductions
A min/max operation is represented by a select(cmp(lt/le/gt/ge, X, Y), X, Y)
sequence in LLVM. If we see such a sequence we can treat it just as any other
commutative binary instruction and reduce it.

This appears to help bzip2 by about 1.5% on an imac12,2.

radar://12960601

llvm-svn: 179773
2013-04-18 17:22:34 +00:00
Benjamin Kramer 8df2cfb858 LoopVectorize: Use a set to avoid longer cycles in the reduction chain too.
Fixes PR15748.

llvm-svn: 179757
2013-04-18 14:29:13 +00:00
Arnold Schwaighofer f9cea17f75 LoopVectorizer: integer division is not a reduction operation
Don't classify idiv/udiv as a reduction operation. Integer division is lossy.
For example : (1 / 2) * 4 != 4/2.

Example:

int a[] = { 2, 5, 2, 2}
int x = 80;

for()
  x /= a[i];

Scalar:
  x /= 2 // = 40
  x /= 5 // = 8
  x /= 2 // = 4
  x /= 2 // = 2

Vectorized:

 <80, 1> / <2,5> //= <40,0>
 <40, 0> / <2,2> //= <20,0>

 20*0 = 0

radar://13640654

llvm-svn: 179381
2013-04-12 15:15:19 +00:00
Arnold Schwaighofer df6f67ed87 LoopVectorizer: Pass OperandValueKind information to the cost model
Pass down the fact that an operand is going to be a vector of constants.

This should bring the performance of MultiSource/Benchmarks/PAQ8p/paq8p on x86
back. It had degraded to scalar performance due to my pervious shift cost change
that made all shifts expensive on x86.

radar://13576547

llvm-svn: 178809
2013-04-04 23:26:27 +00:00
Arnold Schwaighofer c63cf3a0ae LoopVectorize: Invert case when we use a vector cmp value to query select cost
We generate a select with a vectorized condition argument when the condition is
NOT loop invariant. Not the other way around.

llvm-svn: 177098
2013-03-14 18:54:36 +00:00
Benjamin Kramer 6eda79f69a Remove a source of nondeterminism from the LoopVectorizer.
This made us emit runtime checks in a random order. Hopefully bootstrap
miscompares will go away now.

llvm-svn: 176775
2013-03-09 19:22:40 +00:00
Arnold Schwaighofer 8b3dc09400 LoopVectorizer: Ignore all dbg intrinisic
Ignore all DbgIntriniscInfo instructions instead of just DbgValueInst.

llvm-svn: 176769
2013-03-09 16:27:27 +00:00
Arnold Schwaighofer 4090b61ac3 LoopVectorizer: Ignore dbg.value instructions
We want vectorization to happen at -g. Ignore calls to the dbg.value intrinsic
and don't transfer them to the vectorized code.

radar://13378964

llvm-svn: 176768
2013-03-09 15:56:34 +00:00
Benjamin Kramer 37c2d65c5a Insert the reduction start value into the first bypass block to preserve domination.
Fixes PR15344.

llvm-svn: 176701
2013-03-08 16:58:37 +00:00
Nadav Rotem 739e37a0d2 PR14448 - prevent the loop vectorizer from vectorizing the same loop twice.
The LoopVectorizer often runs multiple times on the same function due to inlining.
When this happens the loop vectorizer often vectorizes the same loops multiple times, increasing code size and adding unneeded branches.
With this patch, the vectorizer during vectorization puts metadata on scalar loops and marks them as 'already vectorized' so that it knows to ignore them when it sees them a second time.

PR14448.

llvm-svn: 176399
2013-03-02 01:33:49 +00:00
Benjamin Kramer 12f98fae98 LoopVectorize: Don't hang forever if a PHI only has skipped PHI uses.
Fixes PR15384.

llvm-svn: 176366
2013-03-01 19:07:31 +00:00
Benjamin Kramer dc145816fd LoopVectorize: Vectorize math builtin calls.
This properly asks TargetLibraryInfo if a call is available and if it is, it
can be translated into the corresponding LLVM builtin. We don't vectorize sqrt()
yet because I'm not sure about the semantics for negative numbers. The other
intrinsic should be exact equivalents to the libm functions.

Differential Revision: http://llvm-reviews.chandlerc.com/D465

llvm-svn: 176188
2013-02-27 15:24:19 +00:00
Renato Golin cf928cb53f Allow GlobalValues to vectorize with AliasAnalysis
Storing the load/store instructions with the values
and inspect them using Alias Analysis to make sure
they don't alias, since the GEP pointer operand doesn't
take the offset into account.

Trying hard to not add any extra cost to loads and stores
that don't overlap on global values, AA is *only* calculated
if all of the previous attempts failed.

Using biggest vector register size as the stride for the
vectorization access, as we're being conservative and
the cost model (which calculates the real vectorization
factor) is only run after the legalization phase.

We might re-think this relationship in the future, but
for now, I'd rather be safe than sorry.

llvm-svn: 175818
2013-02-21 22:39:03 +00:00
Benjamin Kramer 0aa2ad6104 LoopVectorize: Simplify code for clarity.
No functionality change.

llvm-svn: 175076
2013-02-13 21:12:29 +00:00
Pekka Jaaskelainen 0d23725a8d Metadata for annotating loops as parallel. The first consumer for this
metadata is the loop vectorizer.

See the documentation update for more info.

llvm-svn: 175060
2013-02-13 18:08:57 +00:00
Jakob Stoklund Olesen 479e5a9313 Typos.
llvm-svn: 174723
2013-02-08 17:43:32 +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
Michael Kuperstein f63b77be7f Test Commit
llvm-svn: 174709
2013-02-08 12:58:29 +00:00
Nadav Rotem a9100f3609 fix 80-col violation and fix the docs.
llvm-svn: 174671
2013-02-07 22:34:07 +00:00
Arnold Schwaighofer 3476fc8c82 Loop Vectorizer: Refactor Memory Cost Computation
We don't want too many classes in a pass and the classes obscure the details. I
was going a little overboard with object modeling here. Replace classes by
generic code that handles both loads and stores.

No functionality change intended.

llvm-svn: 174646
2013-02-07 19:05:21 +00:00
Arnold Schwaighofer 3be40b56c5 Loop Vectorizer: Refactor code to compute vectorized memory instruction cost
Introduce a helper class that computes the cost of memory access instructions.
No functionality change intended.

llvm-svn: 174422
2013-02-05 18:46:41 +00:00
Arnold Schwaighofer 22174f5d5a Loop Vectorizer: Handle pointer stores/loads in getWidestType()
In the loop vectorizer cost model, we used to ignore stores/loads of a pointer
type when computing the widest type within a loop. This meant that if we had
only stores/loads of pointers in a loop we would return a widest type of 8bits
(instead of 32 or 64 bit) and therefore a vector factor that was too big.

Now, if we see a consecutive store/load of pointers we use the size of a pointer
(from data layout).

This problem occured in SingleSource/Benchmarks/Shootout-C++/hash.cpp (reduced
test case is the first test in vector_ptr_load_store.ll).

radar://13139343

llvm-svn: 174377
2013-02-05 15:08:02 +00:00
Pekka Jaaskelainen f50ab84bb1 LoopVectorize: convert TinyTripCountVectorThreshold constant
to a command line switch.

llvm-svn: 173837
2013-01-29 21:42:08 +00:00
Benjamin Kramer cf406756ce LoopVectorize: Clean up ValueMap a bit and avoid double lookups.
No intended functionality change.

llvm-svn: 173809
2013-01-29 17:31:33 +00:00