197 Commits

Author SHA1 Message Date
Arnold Schwaighofer
63eb047996 LoopVectorize: Move call of canHoistAllLoads to canVectorizeWithIfConvert
We only want to check this once, not for every conditional block in the loop.

No functionality change (except that we don't perform a check redudantly
anymore).

llvm-svn: 181942
2013-05-15 22:38:14 +00:00
Arnold Schwaighofer
f8c04c27fc LoopVectorize: Fix comments
No functionality change.

llvm-svn: 181862
2013-05-15 02:02:45 +00:00
Arnold Schwaighofer
0e2020dbaf LoopVectorize: Hoist conditional loads if possible
InstCombine can be uncooperative to vectorization and sink loads into
conditional blocks. This prevents vectorization.

Undo this optimization if there are unconditional memory accesses to the same
addresses in the loop.

radar://13815763

llvm-svn: 181860
2013-05-15 01:44:30 +00:00
Arnold Schwaighofer
5f1c1c6187 LoopVectorize: Handle loops with multiple forward inductions
We used to give up if we saw two integer inductions. After this patch, we base
further induction variables on the chosen one like we do in the reverse
induction and pointer induction case.

Fixes PR15720.

radar://13851975

llvm-svn: 181746
2013-05-14 00:21:18 +00:00
Arnold Schwaighofer
c532e0f494 LoopVectorize: Use the widest induction variable type
Use the widest induction type encountered for the cannonical induction variable.

We used to turn the following loop into an empty loop because we used i8 as
induction variable type and truncated 1024 to 0 as trip count.

int a[1024];
void fail() {
  int reverse_induction = 1023;
  unsigned char forward_induction = 0;
  while ((reverse_induction) >= 0) {
    forward_induction++;
    a[reverse_induction] = forward_induction;
    --reverse_induction;
  }
}

radar://13862901

llvm-svn: 181667
2013-05-11 23:04:28 +00:00
Arnold Schwaighofer
e5f236f9a7 LoopVectorize: Use variable instead of repeated function call
No functionality change intended.

llvm-svn: 181666
2013-05-11 23:04:26 +00:00
Arnold Schwaighofer
062224410c LoopVectorize: Use IRBuilder interface in more places
No functionality change intended.

llvm-svn: 181665
2013-05-11 23:04:24 +00:00
Arnold Schwaighofer
374ad2d113 LoopVectorizer: Don't assert on the absence of induction variables
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
2013-05-09 00:32:18 +00:00
Arnold Schwaighofer
b00b8ac69a LoopVectorizer: Improve reduction variable identification
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
2013-05-07 21:55:37 +00:00
Arnold Schwaighofer
f95f087afb LoopVectorize: getConsecutiveVector must respect signed arithmetic
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
2013-05-07 04:37:05 +00:00
Nadav Rotem
9119c025de Update the comment to mention that we use TTI.
llvm-svn: 181178
2013-05-06 03:06:36 +00:00
Benjamin Kramer
06f30fc527 LoopVectorize: Print values instead of pointers in debug output.
llvm-svn: 181157
2013-05-05 14:54:52 +00:00
Arnold Schwaighofer
0a0d84c7b7 LoopVectorize: Add support for floating point min/max reductions
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
2013-05-05 01:54:48 +00:00
Arnold Schwaighofer
0791ec5e44 LoopVectorizer: Cleanup of miminimum/maximum pattern match code
No need for setting the operands. The pointers are going to be bound by the
matcher.

radar://13723044

llvm-svn: 181142
2013-05-05 01:54:44 +00:00
Arnold Schwaighofer
0158aa58f2 LoopVectorize: We don't need an identity element for min/max reductions
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
2013-05-05 01:54:42 +00:00
Dmitri Gribenko
82c92dc3dd Add ArrayRef constructor from None, and do the cleanups that this constructor enables
Patch by Robert Wilhelm.

llvm-svn: 181138
2013-05-05 00:40:33 +00:00
Nadav Rotem
97fe0281b4 LoopVectorizer: Add support for if-conversion of PHINodes with 3+ incoming values.
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
2013-05-03 17:42:55 +00:00
Nadav Rotem
fe6c769d60 LoopVectorizer: Calculate the number of pointers to disambiguate at runtime based on the numbers of reads and writes.
llvm-svn: 180593
2013-04-26 05:08:59 +00:00
Nadav Rotem
d5eaf768a9 LoopVectorizer: No need to generate pointer disambiguation checks between readonly pointers.
llvm-svn: 180570
2013-04-25 19:55:03 +00:00
Arnold Schwaighofer
b2a88cf3ef LoopVectorizer: Change variable name Stride to ConsecutiveStride
This makes it easier to read the code.

No functionality change.

llvm-svn: 180197
2013-04-24 16:16:03 +00:00
Arnold Schwaighofer
ad591145df LoopVectorize: Scalarize padded types
This patch disables memory-instruction vectorization for types that need padding
bytes, e.g., x86_fp80 has 10 bytes store size with 6 bytes padding in darwin on
x86_64. Because the load/store vectorization is performed by the bit casting to
a packed vector, which has incompatible memory layout due to the lack of padding
bytes, the present vectorizer produces inconsistent result for memory
instructions of those types.
This patch checks an equality of the AllocSize of a scalar type and allocated
size for each vector element, to ensure that there is no padding bytes and the
array can be read/written using vector operations.

Patch by Daisuke Takahashi!

Fixes PR15758.

llvm-svn: 180196
2013-04-24 16:16:01 +00:00
Arnold Schwaighofer
169f004ff2 LoopVectorizer: Bail out if we don't have datalayout we need it
llvm-svn: 180195
2013-04-24 16:15:58 +00:00
Nadav Rotem
1bfb7903e3 LoopVectorizer: Fix 15830. When scalarizing and unrolling stores make sure that the order in which the elements are scalarized is the same as the original order.
This fixes a miscompilation in FreeBSD's regex library.

llvm-svn: 180121
2013-04-23 17:12:42 +00:00
Pekka Jaaskelainen
d8a8d1d02f Call the potentially costly isAnnotatedParallel() only once.
Made the uniform write test's checks a bit stricter.

llvm-svn: 180119
2013-04-23 16:44:43 +00:00
Pekka Jaaskelainen
1492231ce9 Refuse to (even try to) vectorize loops which have uniform writes,
even if erroneously annotated with the parallel loop metadata.

Fixes Bug 15794: 
"Loop Vectorizer: Crashes with the use of llvm.loop.parallel metadata"

llvm-svn: 180081
2013-04-23 08:08:51 +00:00
Arnold Schwaighofer
7b05635869 LoopVectorizer: Use matcher from PatternMatch.h for the min/max patterns
Also make some static function class functions to avoid having to mention the
class namespace for enums all the time.

No functionality change intended.

llvm-svn: 179886
2013-04-19 21:03:36 +00:00
Dmitri Gribenko
ad7b3011a6 Fix a -Wdocumentation warning
llvm-svn: 179789
2013-04-18 20:13:04 +00:00
Arnold Schwaighofer
acd551152c 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
18f31a4d5e 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
48b1c3e915 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
abd363c1bc 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
3e3105f2f8 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
c6db6a4d69 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
2a2a785543 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
652df6a5cb 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
7b2d670a66 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
6d803820f8 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
a462070739 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
33d5dd0b08 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
d371b2ca14 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
7e28d6495d LoopVectorize: Simplify code for clarity.
No functionality change.

llvm-svn: 175076
2013-02-13 21:12:29 +00:00
Pekka Jaaskelainen
7e2908d0f3 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
c8bee11d10 Typos.
llvm-svn: 174723
2013-02-08 17:43:32 +00:00
Arnold Schwaighofer
381c4a3e54 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
ed93eafd8f Test Commit
llvm-svn: 174709
2013-02-08 12:58:29 +00:00
Nadav Rotem
dcab6c8ee5 fix 80-col violation and fix the docs.
llvm-svn: 174671
2013-02-07 22:34:07 +00:00
Arnold Schwaighofer
cae839558d 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
b835fa09f3 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
5ee07db17d 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
67cddcca8c LoopVectorize: convert TinyTripCountVectorThreshold constant
to a command line switch.

llvm-svn: 173837
2013-01-29 21:42:08 +00:00