Commit Graph

6066 Commits

Author SHA1 Message Date
Derek Schuff
87e6561f34 Make NaCl's use of .init_array for static constructors match Linux
Summary:
The generic ELF TargetObjectFile defaults to .ctors, but Linux's
defaults to .init_array by calling InitializeELF with the value of
UseInitArray from TargetMachine. Make NaCl's behavior match.

Reviewers: jvoung
Differential Revision: http://reviews.llvm.org/D8240

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231934 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-11 16:16:09 +00:00
Quentin Colombet
7775242da3 [CodeGenPrepare] Refine the cost model provided by the promotion helper.
- Use TargetLowering to check for the actual cost of each extension.
- Provide a factorized method to check for the cost of an extension:
  TargetLowering::isExtFree.
- Provide a virtual method TargetLowering::isExtFreeImpl for targets to be able
  to tune the cost of non-free extensions.

This refactoring offers a better granularity to model what really happens on
different targets.

No performance changes and very few code differences.

Part of <rdar://problem/19267165> 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231855 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 21:48:15 +00:00
Igor Laevsky
68beb2a9ec Teach lowering to correctly handle invoke statepoint and gc results tied to them. Note that we still can not lower gc.relocates for invoke statepoints.
Also it extracts getCopyFromRegs helper function in SelectionDAGBuilder as we need to be able to customize type of the register exported from basic block during lowering of the gc.result.
(Resubmitting this change after not being able to reproduce buildbot failure)

Differential Revision: http://reviews.llvm.org/D7760



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231800 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 16:26:48 +00:00
Sanjay Patel
137e1f3f28 [X86, AVX] replace vinsertf128 intrinsics with generic shuffles
We want to replace as much custom x86 shuffling via intrinsics
as possible because pushing the code down the generic shuffle
optimization path allows for better codegen and less complexity
in LLVM.

This is the sibling patch for the Clang half of this change:
http://reviews.llvm.org/D8088

Differential Revision: http://reviews.llvm.org/D8086



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231794 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 16:08:36 +00:00
Ahmed Bougacha
55a060641f [CodeGen] Replace the reused stores' chain for extractelt expansion.
This fixes a subtle issue that was introduced in r205153.

When reusing a store for the extractelement expansion (to load directly
from it, inserting of going through the stack), later stores to the
same location might have overwritten the data we were expecting to
extract from.

To fix that, we need to explicitly replace the chain going out of the
reused store, so that later stores also have an explicit dependency on
the generated element-extracting loads, and can't clobber them.

rdar://20066785
Differential Revision: http://reviews.llvm.org/D8180


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231721 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 22:51:05 +00:00
Ahmed Bougacha
fad749559c [X86] Add nounwind to vector-idiv.ll testcases. NFC.
In preparation for a patch where cfi directives get in the way.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231720 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 22:46:02 +00:00
Reid Kleckner
4c27f8d49e Reland r229944: EH: Prune unreachable resume instructions during Dwarf EH preparation
Fix the double-deletion of AnalysisResolver when delegating through to
Dwarf EH preparation by creating one from scratch. Hopefully the new
pass manager simplifies this.

This reverts commit r229952.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231719 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 22:45:16 +00:00
Rafael Espindola
be886690bd Print jump tables before exception tables.
In the case where just tables are part of the function section, this produces
more readable assembly by avoiding switching to the eh section and back
to .text.

This would also break with non unique section names, as trying to switch to
a unique section actually creates a new one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231677 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 18:29:12 +00:00
Andrea Di Biagio
d1232fa1c0 Fix line ending in test CodeGen/X86/pr22774.ll. NFC.
Also, replaced line with 'target triple' with flag -mtriple on the RUN line.
Removed the data layout string as it is not needed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231654 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 15:02:01 +00:00
Andrea Di Biagio
692f7382b5 [X86][AVX] Fix wrong lowering of VPERM2X128 nodes
There were cases where the backend computed a wrong permute mask for a VPERM2X128 node.

Example:
\code
define <8 x float> @foo(<8 x float> %a, <8 x float> %b) {
  %shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 undef, i32 undef, i32 6, i32 7>
  ret <8 x float> %shuffle
}
\code end

Before this patch, llc (with -mattr=+avx) emitted the following vperm2f128:
  vperm2f128 $0, %ymm0, %ymm0, %ymm0  # ymm0 = ymm0[0,1,0,1]

With this patch, llc emits a vperm2f128 with a correct permute mask:
  vperm2f128 $17, %ymm0, %ymm0, %ymm0  # ymm0 = ymm0[2,3,2,3]

Differential Revision: http://reviews.llvm.org/D8119


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231601 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-08 16:28:47 +00:00
Andrea Di Biagio
15d2c3fb00 [DAGCombiner] Fix wrong folding of AND dag nodes.
This patch fixes the logic in the DAGCombiner that folds an AND node according
to rule: (and (X (load V)), C) -> (X (load V))

An AND between a vector load 'X' and a constant build_vector 'C' can be folded
into the load itself only if we can prove that the AND operation is redundant.
The algorithm implemented by 'visitAND' firstly computes the splat value 'S'
from C, and then checks if S has the lower 'B' bits set (where B is the size in
bits of the vector element type). The algorithm takes into account also the
'undef' bits in the splat mask.

Unfortunately, the algorithm only worked under the assumption that the size of S
is a multiple of the vector element type. With this patch, we conservatively
avoid folding the AND if the splat bits are not compatible with the vector
element type.

Added X86 test and-load-fold.ll

Differential Revision: http://reviews.llvm.org/D8085


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231563 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-07 12:24:55 +00:00
Simon Pilgrim
62ba058dea [DAGCombiner] SCALAR_TO_VECTOR(EXTRACT_VECTOR_ELT(V,C)) -> VECTOR_SHUFFLE
This patch attempts to convert a SCALAR_TO_VECTOR using an operand from an EXTRACT_VECTOR_ELT into a VECTOR_SHUFFLE.

This prevents many cases of spilling scalar data between the gpr + simd registers. 

At present the optimization only accepts cases where there is no TRUNC of the scalar type (i.e. all types must match).

Differential Revision: http://reviews.llvm.org/D8132

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231554 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-07 05:52:42 +00:00
Sanjay Patel
5bac8f9b95 fixed to test features, not CPUs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231524 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:50:42 +00:00
Sanjay Patel
f528a40240 fixed to test features, not CPUs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231523 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:50:27 +00:00
Sanjay Patel
5ff9d3e6ed loosen checking for buildbots
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231522 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:30:18 +00:00
Sanjay Patel
aedb16fc6f fixed to test only the feature, not the feature and a CPU
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231521 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:24:56 +00:00
Sanjay Patel
b00a131bda fixed to test only the feature, not the feature and a CPU
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231520 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:19:32 +00:00
Sanjay Patel
50652e746b fixed test to use FileCheck
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231519 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:16:15 +00:00
Sanjay Patel
6deb05e63a fixed to use CHECK-LABELs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231517 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 21:05:02 +00:00
Sanjay Patel
d532d10275 fixed to test only the feature, not the feature and a CPU
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231516 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 20:58:15 +00:00
Sanjay Patel
f2b34a568b fixed to test only the feature, not the feature and a CPU
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231515 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 20:57:40 +00:00
Sanjay Patel
9e03e85cac fixed to test feature, not CPU
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231513 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 20:51:25 +00:00
Sanjay Patel
17392758a1 fixed to test features, not CPUs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231512 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 20:46:16 +00:00
Sanjay Patel
91b79125ec fixed test to use SSE2 attribute
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231510 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 20:38:55 +00:00
Sanjay Patel
e7abe0cdbc fixed to test only the feature, not the feature and a CPU
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231509 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 20:34:20 +00:00
Matthias Braun
47941aa098 DAGCombiner: Canonicalize select(and/or,x,y) depending on target.
This is based on the following equivalences:
select(C0 & C1, X, Y) <=> select(C0, select(C1, X, Y), Y)
select(C0 | C1, X, Y) <=> select(C0, X, select(C1, X, Y))

Many target cannot perform and/or on the CPU flags and therefore the
right side should be choosen to avoid materializign the i1 flags in an
integer register. If the target can perform this operation efficiently
we normalize to the left form.

Differential Revision: http://reviews.llvm.org/D7622

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231507 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 19:49:10 +00:00
Michael Zolotukhin
6023ad2d37 LegalizeTypes: Handle shift by 0 in ExpandShiftByConstant.
Though such shifts are usually optimized away by combiner, we still can
encounter them after a vector shift is legalized.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231443 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-06 01:13:01 +00:00
Sanjay Patel
5f79fd2f02 [AVX] Lower / fast-isel scalar FP selects into VBLENDV instructions (PR22483)
This patch reduces code size for all AVX targets and increases speed for some chips.

SSE 4.1 introduced the useless (see code comments) 2-register form of BLENDV and
only in the packed float/double flavors.

AVX subsequently made the instruction useful by adding a 4-register operand form.

So we just need to paper over the lack of scalar forms of this instruction, complicate
the code to choose float or double forms, and use blendv on scalars since all FP is in
xmm registers anyway.

This gives us an approximately 50% speed up for a blendv microbenchmark sequence
on SandyBridge and Haswell:
blendv : 29.73 cycles/iter
logic : 43.15 cycles/iter

No new test cases with this patch because:

1. fast-isel-select-sse.ll tests the positive side for regular X86 lowering and fast-isel
2. sse-minmax.ll and fp-select-cmp-and.ll confirm that we're not firing for scalar selects without AVX
3. fp-select-cmp-and.ll and logical-load-fold.ll confirm that we're not firing for scalar selects with constants.

http://llvm.org/bugs/show_bug.cgi?id=22483

Differential Revision: http://reviews.llvm.org/D8063



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231408 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 21:46:54 +00:00
David Majnemer
42fcf79f36 X86: Optimize address mode matching for FRAME_ALLOC_RECOVER nodes
We know that the absolute symbol will be less than 2GB and thus will
always fit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231389 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 18:50:12 +00:00
Reid Kleckner
9f7c861416 Replace llvm.frameallocate with llvm.frameescape
Turns out it's pretty straightforward and simplifies the implementation.

Reviewers: andrew.w.kaylor

Differential Revision: http://reviews.llvm.org/D8051

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231386 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 18:26:34 +00:00
Simon Pilgrim
a744a15e97 [DagCombiner] Allow shuffles to merge through bitcasts
Currently shuffles may only be combined if they are of the same type, despite the fact that bitcasts are often introduced in between shuffle nodes (e.g. x86 shuffle type widening).

This patch allows a single input shuffle to peek through bitcasts and if the input is another shuffle will merge them, shuffling using the smallest sized type, and re-applying the bitcasts at the inputs and output instead.

Dropped old ShuffleToZext test - this patch removes the use of the zext and vector-zext.ll covers these anyhow.

Differential Revision: http://reviews.llvm.org/D7939

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231380 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 17:14:04 +00:00
Igor Laevsky
684d323b9b Revert change r231366 as it broke clang-native-arm-cortex-a9 Analysis/properties.m test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231374 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 15:41:14 +00:00
Elena Demikhovsky
e670dc7848 AVX-512, SKX: Enabled masked_load/store operations for this target.
Added lowering for ISD::CONCAT_VECTORS and ISD::INSERT_SUBVECTOR for i1 vectors,
it is needed to pass all masked_memop.ll tests for SKX.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231371 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 15:11:35 +00:00
Igor Laevsky
f8b3003ab8 Teach lowering to correctly handle invoke statepoint and gc results tied to them. Note that we still can not lower gc.relocates for invoke statepoints.
Also it extracts getCopyFromRegs helper function in SelectionDAGBuilder as we need to be able to customize type of the register exported from basic block during lowering of the gc.result.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231366 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 14:11:21 +00:00
Craig Topper
62eaac6087 [X86] Use vmovss to handle inserting an element into index 0 of a v8f32 vector of zeros.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231354 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 06:38:42 +00:00
Chandler Carruth
4197c13062 [MBP] Revert r231238 which attempted to fix a nasty bug where MBP is
just arbitrarily interleaving unrelated control flows once they get
moved "out-of-line" (both outside of natural CFG ordering and with
diamonds that cannot be fully laid out by chaining fallthrough edges).

This easy solution doesn't work in practice, and it isn't just a small
bug. It looks like a very different strategy will be required. I'm
working on that now, and it'll again go behind some flag so that
everyone can experiment and make sure it is working well for them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231332 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 01:07:03 +00:00
Andrea Di Biagio
da5e5688e9 [X86][FastISel] Simplify the logic in method X86SelectSIToFP.
The target-independent selection algorithm in FastISel already knows how
to select a SINT_TO_FP if the target is SSE but not AVX.

On targets that have SSE but not AVX, the tablegen'd 'fastEmit' functions
for ISD::SINT_TO_FP know how to select instruction X86::CVTSI2SSrr
(for an i32 to f32 conversion) and X86::CVTSI2SDrr (for an i32 to f64
conversion).

This patch simplifies the logic in method X86SelectSIToFP knowing that
the code would not be reachable if the subtarget doesn't have AVX.
No functional change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231243 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 14:23:25 +00:00
Chandler Carruth
67fade9110 [MBP] Fix a really horrible bug in MachineBlockPlacement, but behind
a flag for now.

First off, thanks to Daniel Jasper for really pointing out the issue
here. It's been here forever (at least, I think it was there when
I first wrote this code) without getting really noticed or fixed.

The key problem is what happens when two reasonably common patterns
happen at the same time: we outline multiple cold regions of code, and
those regions in turn have diamonds or other CFGs for which we can't
just topologically lay them out. Consider some C code that looks like:

  if (a1()) { if (b1()) c1(); else d1(); f1(); }
  if (a2()) { if (b2()) c2(); else d2(); f2(); }
  done();

Now consider the case where a1() and a2() are unlikely to be true. In
that case, we might lay out the first part of the function like:

  a1, a2, done;

And then we will be out of successors in which to build the chain. We go
to find the best block to continue the chain with, which is perfectly
reasonable here, and find "b1" let's say. Laying out successors gets us
to:

  a1, a2, done; b1, c1;

At this point, we will refuse to lay out the successor to c1 (f1)
because there are still un-placed predecessors of f1 and we want to try
to preserve the CFG structure. So we go get the next best block, d1.

... wait for it ...

Except that the next best block *isn't* d1. It is b2! d1 is waaay down
inside these conditionals. It is much less important than b2. Except
that this is exactly what we didn't want. If we keep going we get the
entire set of the rest of the CFG *interleaved*!!!

  a1, a2, done; b1, c1; b2, c2; d1, f1; d2, f2;

So we clearly need a better strategy here. =] My current favorite
strategy is to actually try to place the block whose predecessor is
closest. This very simply ensures that we unwind these kinds of CFGs the
way that is natural and fitting, and should minimize the number of cache
lines instructions are spread across.

It also happens to be *dead simple*. It's like the datastructure was
specifically set up for this use case or something. We only push blocks
onto the work list when the last predecessor for them is placed into the
chain. So the back of the worklist *is* the nearest next block.

Unfortunately, a change like this is going to cause *soooo* many
benchmarks to swing wildly. So for now I'm adding this under a flag so
that we and others can validate that this is fixing the problems
described, that it seems possible to enable, and hopefully that it fixes
more of our problems long term.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231238 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 12:18:08 +00:00
Daniel Jasper
f68f28a41d Add a flag to experiment with outlining optional branches.
In a CFG with the edges A->B->C and A->C, B is an optional branch.

LLVM's default behavior is to lay the blocks out naturally, i.e. A, B,
C, in order to improve code locality and fallthroughs. However, if a
function contains many of those optional branches only a few of which
are taken, this leads to a lot of unnecessary icache misses. Moving B
out of line can work around this.

Review: http://reviews.llvm.org/D7719

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231230 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 11:05:34 +00:00
Michael Kuperstein
bbfda9c125 [DAGCombine] Fix a bug in a BUILD_VECTOR combine
When trying to convert a BUILD_VECTOR into a shuffle, we try to split a single source vector that is twice as wide as the destination vector. 
We can not do this when we also need the zero vector to create a blend.
This fixes PR22774.

Differential Revision: http://reviews.llvm.org/D8040

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231219 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 07:27:39 +00:00
Filipe Cabecinhas
7eefc249b8 Fix the test for r231201. We don't crash anymore.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231207 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 02:09:40 +00:00
Rafael Espindola
bd490c174e Use the vanilla func_end symbol for .size.
No need to create yet another temp symbol.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231198 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 01:35:23 +00:00
Eric Christopher
1df6d33c5e Weaken the check for a specific movl on the twoaddr-coalesce-3
test - we only care that there are two moves in the loop and not
which part is relative to which register anyhow.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231191 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 01:19:17 +00:00
Filipe Cabecinhas
08efe825e4 Fix the x86-upgrade-avx2-vbroadcast.ll test by commenting the CHECK lines
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231187 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 00:49:12 +00:00
Rafael Espindola
c82398a2ac Drop the "eh_" from eh_func_begin and eh_func_end.
They will be used for more than eh tables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231185 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 00:27:43 +00:00
Juergen Ributzka
e49da9aff1 Remove 'llvm.x86.avx2.vbroadcasti128' intrinsic.
The intrinsic is no longer generated by the front-end. Remove the intrinsic and
auto-upgrade it to a vector shuffle.

Reviewed by Nadav

This is related to rdar://problem/18742778.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231182 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 00:13:25 +00:00
Eric Christopher
f2bf51c593 Update twoaddr-coalesce-3.ll to run on darwin and linux machines:
a) Default relocation model differences,
b) Different numbers of # in comments

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231178 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 23:56:20 +00:00
Andrew Kaylor
92dabb5710 Moving WinEH outlining tests to an architecture neutral location
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231155 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 22:33:39 +00:00
Eric Christopher
63295d884c Fix a problem where the TwoAddressInstructionPass which generate redundant register moves in a loop.
From:
int M, total;
void foo() {
int i;
for (i = 0; i < M; i++) {
  total = total + i / 2;
}
}

This is the kernel loop:

.LBB0_2: # %for.body

=>This Inner Loop Header: Depth=1
movl %edx, %esi
movl %ecx, %edx
shrl $31, %edx
addl %ecx, %edx
sarl %edx
addl %esi, %edx
incl %ecx
cmpl %eax, %ecx
jl .LBB0_2
--------------------------
The first mov insn "movl %edx, %esi" could be removed if we change "addl %esi, %edx" to "addl %edx, %esi".

The IR before TwoAddressInstructionPass is:
BB#2: derived from LLVM BB %for.body

Predecessors according to CFG: BB#1 BB#2
    %vreg3<def> = COPY %vreg12<kill>; GR32:%vreg3,%vreg12
    %vreg2<def> = COPY %vreg11<kill>; GR32:%vreg2,%vreg11
    %vreg7<def,tied1> = SHR32ri %vreg3<tied0>, 31, %EFLAGS<imp-def,dead>; GR32:%vreg7,%vreg3
    %vreg8<def,tied1> = ADD32rr %vreg3<tied0>, %vreg7<kill>, %EFLAGS<imp-def,dead>; GR32:%vreg8,%vreg3,%vreg7
    %vreg9<def,tied1> = SAR32r1 %vreg8<kill,tied0>, %EFLAGS<imp-def,dead>; GR32:%vreg9,%vreg8
    %vreg4<def,tied1> = ADD32rr %vreg9<kill,tied0>, %vreg2<kill>, %EFLAGS<imp-def,dead>; GR32:%vreg4,%vreg9,%vreg2
    %vreg5<def,tied1> = INC64_32r %vreg3<kill,tied0>, %EFLAGS<imp-def,dead>; GR32:%vreg5,%vreg3
    CMP32rr %vreg5, %vreg0, %EFLAGS<imp-def>; GR32:%vreg5,%vreg0
    %vreg11<def> = COPY %vreg4; GR32:%vreg11,%vreg4
    %vreg12<def> = COPY %vreg5<kill>; GR32:%vreg12,%vreg5
    JL_4 <BB#2>, %EFLAGS<imp-use,kill>
Now TwoAddressInstructionPass will choose vreg9 to be tied with vreg4. However, it doesn't see that there is copy from vreg4 to vreg11 and another copy from vreg11 to vreg2 inside the loop body. To remove those copies, it is necessary to choose vreg2 to be tied with vreg4 instead of vreg9. This code pattern commonly appears when there is reduction operation in a loop.

So check for a reversed copy chain and if we encounter one then we can commute the add instruction so we can avoid a copy.

Patch by Wei Mi.
http://reviews.llvm.org/D7806

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231148 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 22:03:03 +00:00
Andrew Kaylor
83eaade2b4 Outline cleanup handlers for native Windows C++ exception handling
Differential Revision: http://reviews.llvm.org/D7865



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231117 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 20:00:16 +00:00