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Author SHA1 Message Date
Jim Grosbach 563983c8a3 Legalize vector truncates by parts rather than just splitting. 
Rather than just splitting the input type and hoping for the best, apply
a bit more cleverness. Just splitting the types until the source is
legal often leads to an illegal result time, which is then widened and a
scalarization step is introduced which leads to truly horrible code
generation. With the loop vectorizer, these sorts of operations are much
more common, and so it's worth extra effort to do them well.

Add a legalization hook for the operands of a TRUNCATE node, which will
be encountered after the result type has been legalized, but if the
operand type is still illegal. If simple splitting of both types
ends up with the result type of each half still being legal, just
do that (v16i16 -> v16i8 on ARM, for example). If, however, that would
result in an illegal result type (v8i32 -> v8i8 on ARM, for example),
we can get more clever with power-two vectors. Specifically,
split the input type, but also widen the result element size, then
concatenate the halves and truncate again.  For example on ARM,
To perform a "%res = v8i8 trunc v8i32 %in" we transform to:
  %inlo = v4i32 extract_subvector %in, 0
  %inhi = v4i32 extract_subvector %in, 4
  %lo16 = v4i16 trunc v4i32 %inlo
  %hi16 = v4i16 trunc v4i32 %inhi
  %in16 = v8i16 concat_vectors v4i16 %lo16, v4i16 %hi16
  %res = v8i8 trunc v8i16 %in16

This allows instruction selection to generate three VMOVN instructions
instead of a sequences of moves, stores and loads.

Update the ARMTargetTransformInfo to take this improved legalization
into account.

Consider the simplified IR:

define <16 x i8> @test1(<16 x i32>* %ap) {
  %a = load <16 x i32>* %ap
  %tmp = trunc <16 x i32> %a to <16 x i8>
  ret <16 x i8> %tmp
}

define <8 x i8> @test2(<8 x i32>* %ap) {
  %a = load <8 x i32>* %ap
  %tmp = trunc <8 x i32> %a to <8 x i8>
  ret <8 x i8> %tmp
}

Previously, we would generate the truly hideous:
	.syntax unified
	.section	__TEXT,__text,regular,pure_instructions
	.globl	_test1
	.align	2
_test1:                                 @ @test1
@ BB#0:
	push	{r7}
	mov	r7, sp
	sub	sp, sp, #20
	bic	sp, sp, #7
	add	r1, r0, #48
	add	r2, r0, #32
	vld1.64	{d24, d25}, [r0:128]
	vld1.64	{d16, d17}, [r1:128]
	vld1.64	{d18, d19}, [r2:128]
	add	r1, r0, #16
	vmovn.i32	d22, q8
	vld1.64	{d16, d17}, [r1:128]
	vmovn.i32	d20, q9
	vmovn.i32	d18, q12
	vmov.u16	r0, d22[3]
	strb	r0, [sp, #15]
	vmov.u16	r0, d22[2]
	strb	r0, [sp, #14]
	vmov.u16	r0, d22[1]
	strb	r0, [sp, #13]
	vmov.u16	r0, d22[0]
	vmovn.i32	d16, q8
	strb	r0, [sp, #12]
	vmov.u16	r0, d20[3]
	strb	r0, [sp, #11]
	vmov.u16	r0, d20[2]
	strb	r0, [sp, #10]
	vmov.u16	r0, d20[1]
	strb	r0, [sp, #9]
	vmov.u16	r0, d20[0]
	strb	r0, [sp, #8]
	vmov.u16	r0, d18[3]
	strb	r0, [sp, #3]
	vmov.u16	r0, d18[2]
	strb	r0, [sp, #2]
	vmov.u16	r0, d18[1]
	strb	r0, [sp, #1]
	vmov.u16	r0, d18[0]
	strb	r0, [sp]
	vmov.u16	r0, d16[3]
	strb	r0, [sp, #7]
	vmov.u16	r0, d16[2]
	strb	r0, [sp, #6]
	vmov.u16	r0, d16[1]
	strb	r0, [sp, #5]
	vmov.u16	r0, d16[0]
	strb	r0, [sp, #4]
	vldmia	sp, {d16, d17}
	vmov	r0, r1, d16
	vmov	r2, r3, d17
	mov	sp, r7
	pop	{r7}
	bx	lr

	.globl	_test2
	.align	2
_test2:                                 @ @test2
@ BB#0:
	push	{r7}
	mov	r7, sp
	sub	sp, sp, #12
	bic	sp, sp, #7
	vld1.64	{d16, d17}, [r0:128]
	add	r0, r0, #16
	vld1.64	{d20, d21}, [r0:128]
	vmovn.i32	d18, q8
	vmov.u16	r0, d18[3]
	vmovn.i32	d16, q10
	strb	r0, [sp, #3]
	vmov.u16	r0, d18[2]
	strb	r0, [sp, #2]
	vmov.u16	r0, d18[1]
	strb	r0, [sp, #1]
	vmov.u16	r0, d18[0]
	strb	r0, [sp]
	vmov.u16	r0, d16[3]
	strb	r0, [sp, #7]
	vmov.u16	r0, d16[2]
	strb	r0, [sp, #6]
	vmov.u16	r0, d16[1]
	strb	r0, [sp, #5]
	vmov.u16	r0, d16[0]
	strb	r0, [sp, #4]
	ldm	sp, {r0, r1}
	mov	sp, r7
	pop	{r7}
	bx	lr

Now, however, we generate the much more straightforward:
	.syntax unified
	.section	__TEXT,__text,regular,pure_instructions
	.globl	_test1
	.align	2
_test1:                                 @ @test1
@ BB#0:
	add	r1, r0, #48
	add	r2, r0, #32
	vld1.64	{d20, d21}, [r0:128]
	vld1.64	{d16, d17}, [r1:128]
	add	r1, r0, #16
	vld1.64	{d18, d19}, [r2:128]
	vld1.64	{d22, d23}, [r1:128]
	vmovn.i32	d17, q8
	vmovn.i32	d16, q9
	vmovn.i32	d18, q10
	vmovn.i32	d19, q11
	vmovn.i16	d17, q8
	vmovn.i16	d16, q9
	vmov	r0, r1, d16
	vmov	r2, r3, d17
	bx	lr

	.globl	_test2
	.align	2
_test2:                                 @ @test2
@ BB#0:
	vld1.64	{d16, d17}, [r0:128]
	add	r0, r0, #16
	vld1.64	{d18, d19}, [r0:128]
	vmovn.i32	d16, q8
	vmovn.i32	d17, q9
	vmovn.i16	d16, q8
	vmov	r0, r1, d16
	bx	lr

llvm-svn: 179989
 2013-04-21 23:47:41 +00:00
Arnold Schwaighofer c0c7ff4ac0 X86 cost model: Exit before calling getSimpleVT on non-simple VTs 
getSimpleVT can only handle simple value types.

radar://13676022

llvm-svn: 179714
 2013-04-17 20:04:53 +00:00
Nadav Rotem 87a0af6e1b CostModel: increase the default cost of supported floating point operations from 1 to two. Fixed a few tests that changes because now the cost of one insert + a vector operation on two doubles is lower than two scalar operations on doubles. 
llvm-svn: 179413
 2013-04-12 21:15:03 +00:00
Manman Ren 06a9d50a35 Aliasing rules for struct-path aware TBAA. 
Added PathAliases to check if two struct-path tags can alias.
Added command line option -struct-path-tbaa.

llvm-svn: 179337
 2013-04-11 23:24:18 +00:00
Arnold Schwaighofer f47d2d7f6b X86 cost model: Model cost for uitofp and sitofp on SSE2 
The costs are overfitted so that I can still use the legalization factor.

For example the following kernel has about half the throughput vectorized than
unvectorized when compiled with SSE2. Before this patch we would vectorize it.

unsigned short A[1024];
double B[1024];
void f() {
  int i;
  for (i = 0; i < 1024; ++i) {
    B[i] = (double) A[i];
  }
}

radar://13599001

llvm-svn: 179033
 2013-04-08 18:05:48 +00:00
Arnold Schwaighofer 995ce6c388 TargetLowering: Fix getTypeConversion handling of extended vector types 
The code in getTypeConversion attempts to promote the element vector type
before it trys to split or widen the vector.
After it failed finding a legal vector type by promoting it would continue using
the promoted vector element type. Thereby missing legal splitted vector types.
For example the type v32i32 that has a legal split of 4 x v3i32 on x86/sse2
would be transformed to: v32i256 and from there on successively split to:
v16i256, v8i256, v1i256 and then finally ends up as an i64 type.
By resetting the vector element type to the original vector element type that
existed before the promotion the code will attempt to split the vector type to
smaller vector widths of the same type.

llvm-svn: 178999
 2013-04-07 20:22:56 +00:00
Arnold Schwaighofer 44f902ed7d X86 cost model: Differentiate cost for vector shifts of constants 
SSE2 has efficient support for shifts by a scalar. My previous change of making
shifts expensive did not take this into account marking all shifts as expensive.
This would prevent vectorization from happening where it is actually beneficial.

With this change we differentiate between shifts of constants and other shifts.

radar://13576547

llvm-svn: 178808
 2013-04-04 23:26:24 +00:00
Arnold Schwaighofer e9b5016411 X86 cost model: Vector shifts are expensive in most cases 
The default logic does not correctly identify costs of casts because they are
marked as custom on x86.

For some cases, where the shift amount is a scalar we would be able to generate
better code. Unfortunately, when this is the case the value (the splat) will get
hoisted out of the loop, thereby making it invisible to ISel.

radar://13130673
radar://13537826

llvm-svn: 178703
 2013-04-03 21:46:05 +00:00
Benjamin Kramer 52ceb44331 X86TTI: Add accurate costs for itofp operations, based on the actual instruction counts. 
llvm-svn: 178459
 2013-04-01 10:23:49 +00:00
Andrew Trick 9093e15066 Fix SCEV forgetMemoizedResults should search and destroy backedge exprs. 
Fixes PR15570: SEGV: SCEV back-edge info invalid after dead code removal.

Indvars creates a SCEV expression for the loop's back edge taken
count, then determines that the comparison is always true and
removes it.

When loop-unroll asks for the expression, it contains a NULL
SCEVUnknkown (as a CallbackVH).

forgetMemoizedResults should invalidate the loop back edges expression.

llvm-svn: 177986
 2013-03-26 03:14:53 +00:00
Jyotsna Verma 5bd02926b4 Disable profiling tests for Hexagon since it doesn't support JIT. 
llvm-svn: 177917
 2013-03-25 21:15:11 +00:00
Manman Ren 0827e97700 Support in AAEvaluator to print alias queries of loads/stores with TBAA tags. 
Add "evaluate-tbaa" to print alias queries of loads/stores. Alias queries
between pointers do not include TBAA tags.

Add testing case for "placement new". TBAA currently says NoAlias.

llvm-svn: 177772
 2013-03-22 22:34:41 +00:00
Michael Liao 70dd7f999d Correct cost model for vector shift on AVX2 
- After moving logic recognizing vector shift with scalar amount from
  DAG combining into DAG lowering, we declare to customize all vector
  shifts even vector shift on AVX is legal. As a result, the cost model
  needs special tuning to identify these legal cases.

llvm-svn: 177586
 2013-03-20 22:01:10 +00:00
Nadav Rotem 0f1bc60d51 Optimize sext <4 x i8> and <4 x i16> to <4 x i64>. 
Patch by Ahmad, Muhammad T <muhammad.t.ahmad@intel.com>

llvm-svn: 177421
 2013-03-19 18:38:27 +00:00
Renato Golin 227eb6fc5f 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

llvm-svn: 177380
 2013-03-19 08:15:38 +00:00
Arnold Schwaighofer ae0052f114 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

llvm-svn: 177334
 2013-03-18 22:47:09 +00:00
Arnold Schwaighofer 6c9c3a8b99 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

llvm-svn: 177333
 2013-03-18 22:47:06 +00:00
Arnold Schwaighofer 9d7a3827e4 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

llvm-svn: 177170
 2013-03-15 18:31:01 +00:00
Arnold Schwaighofer f5284ff61f ARM cost model: Fix cost of fptrunc and fpext instructions 
A vector fptrunc and fpext simply gets split into scalar instructions.

radar://13192358

llvm-svn: 177159
 2013-03-15 15:10:47 +00:00
Arnold Schwaighofer 8070b382ec 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

llvm-svn: 177105
 2013-03-14 19:17:02 +00:00
Arnold Schwaighofer 90774f3c8f 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

llvm-svn: 176898
 2013-03-12 21:19:22 +00:00
Jan Wen Voung 6dc3076080 Revert the test moves from 176733. Use "REQUIRES: asserts" instead. 
llvm-svn: 176873
 2013-03-12 16:27:52 +00:00
Jan Wen Voung 7857a64909 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

llvm-svn: 176733
 2013-03-08 22:56:31 +00:00
Shuxin Yang 408bdad5b4 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.

llvm-svn: 176562
 2013-03-06 17:48:48 +00:00
Arnold Schwaighofer 20ef54f4c1 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

llvm-svn: 176403
 2013-03-02 04:02:52 +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
Bill Wendling a032374ea0 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.

llvm-svn: 175877
 2013-02-22 09:09:42 +00:00
Elena Demikhovsky 0ccdd1315b 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.

llvm-svn: 175619
 2013-02-20 12:42:54 +00:00
Bill Wendling 90bc19cd91 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 }

llvm-svn: 175605
 2013-02-20 07:21:42 +00:00
Tim Northover 67d3c09332 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.

llvm-svn: 175433
 2013-02-18 11:08:37 +00:00
Arnold Schwaighofer 89aef93841 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

llvm-svn: 174933
 2013-02-12 02:40:39 +00:00
Bill Schmidt 62fe7a5b17 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.

llvm-svn: 174725
 2013-02-08 18:19:17 +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
Arnold Schwaighofer 213fced704 ARM cost model: Add costs for vector selects 
Vector selects are cheap on NEON. They get lowered to a vbsl instruction.

radar://13158753

llvm-svn: 174631
 2013-02-07 16:10:15 +00:00
Arnold Schwaighofer a804bbee9b ARM cost model: Cost for scalar integer casts and floating point conversions 
Also adds some costs for vector integer float conversions.

llvm-svn: 174371
 2013-02-05 14:05:55 +00:00
Arnold Schwaighofer 98f1012f9b 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

llvm-svn: 174300
 2013-02-04 02:52:05 +00:00
Hal Finkel 4e5ca9e578 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).

llvm-svn: 173520
 2013-01-25 23:05:59 +00:00
Nadav Rotem b1615b1ac4 Make opt grab the triple from the module and use it to initialize the target machine. 
llvm-svn: 171341
 2013-01-01 08:00:32 +00:00
Dmitri Gribenko 56bf2e1830 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.

llvm-svn: 171250
 2012-12-30 02:33:22 +00:00
Dmitri Gribenko 10c4b4d249 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).

llvm-svn: 171248
 2012-12-30 01:42:34 +00:00
Dmitri Gribenko b137c9e551 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.

llvm-svn: 171246
 2012-12-30 01:28:40 +00:00
Nadav Rotem aa92ea4f12 We are not ready to estimate the cost of integer expansions based on the number of parts. This test is too noisy. 
llvm-svn: 170999
 2012-12-23 09:11:07 +00:00
Nadav Rotem 6d4fdd6d2c Improve the X86 cost model for loads and stores. 
llvm-svn: 170830
 2012-12-21 01:33:59 +00:00
Jakub Staszak 338863a546 Reverse order of checking SSE level when calculating compare cost, so we check 
AVX2 before AVX.

llvm-svn: 170464
 2012-12-18 22:57:56 +00:00
Arnold Schwaighofer edd62b14e5 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.

llvm-svn: 169788
 2012-12-10 23:02:41 +00:00
Nadav Rotem 0a471ea66c Cost Model: change the default cost of control flow instructions (br / ret / ...) to zero. 
llvm-svn: 169423
 2012-12-05 21:21:26 +00:00
Preston Briggs fd0b5c898a Modified dump() to provide a little 
more information for dependences between
instructions that don't share a common loop.

Updated the test results appropriately.

llvm-svn: 168965
 2012-11-30 00:44:47 +00:00
Preston Briggs 5cb8cfae1e 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.

llvm-svn: 168719
 2012-11-27 19:12:26 +00:00
Preston Briggs 1084fa2ef2 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.

llvm-svn: 168678
 2012-11-27 06:41:46 +00:00
Preston Briggs 3ad394931d 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!

llvm-svn: 168474
 2012-11-21 23:50:04 +00:00