Commit Graph

11234 Commits

Author SHA1 Message Date
Sanjay Patel
af0a07822e use local variables; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228452 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 22:43:52 +00:00
Reid Kleckner
6dc42dd2da Don't dllexport declarations
Fixes PR22488

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228411 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 17:59:49 +00:00
Benjamin Kramer
e003f1ac8c Make helper functions/classes/globals static. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228410 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 17:51:54 +00:00
Eric Christopher
a4ed04095c Remove the use of getSubtarget in the creation of the X86
PassManager instance. In one case we can make the determination
from the Triple, in the other (execution dependency pass) the
pass will avoid running if we don't have any code that uses that
register class so go ahead and add it to the pipeline.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228334 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 19:27:04 +00:00
Eric Christopher
3e68370c22 Use cached subtargets inside X86FixupLEAs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228333 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 19:27:01 +00:00
Eric Christopher
d63e18f179 Migrate the X86 AsmPrinter away from using the subtarget when
dealing with module level emission. Currently this is using
the Triple to determine, but eventually the logic should
probably migrate to TLOF.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228332 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 19:06:45 +00:00
Ahmed Bougacha
ec35069525 [CodeGen] Add hook/combine to form vector extloads, enabled on X86.
The combine that forms extloads used to be disabled on vector types,
because "None of the supported targets knows how to perform load and
sign extend on vectors in one instruction."

That's not entirely true, since at least SSE4.1 X86 knows how to do
those sextloads/zextloads (with PMOVS/ZX).
But there are several aspects to getting this right.
First, vector extloads are controlled by a profitability callback.
For instance, on ARM, several instructions have folded extload forms,
so it's not always beneficial to create an extload node (and trying to
match extloads is a whole 'nother can of worms).

The interesting optimization enables folding of s/zextloads to illegal
(splittable) vector types, expanding them into smaller legal extloads.

It's not ideal (it introduces some legalization-like behavior in the
combine) but it's better than the obvious alternative: form illegal
extloads, and later try to split them up.  If you do that, you might
generate extloads that can't be split up, but have a valid ext+load
expansion.  At vector-op legalization time, it's too late to generate
this kind of code, so you end up forced to scalarize. It's better to
just avoid creating egregiously illegal nodes.

This optimization is enabled unconditionally on X86.

Note that the splitting combine is happy with "custom" extloads. As
is, this bypasses the actual custom lowering, and just unrolls the
extload. But from what I've seen, this is still much better than the
current custom lowering, which does some kind of unrolling at the end
anyway (see for instance load_sext_4i8_to_4i64 on SSE2, and the added
FIXME).

Also note that the existing combine that forms extloads is now also
enabled on legal vectors.  This doesn't have a big effect on X86
(because sext+load is usually combined to sext_inreg+aextload).
On ARM it fires on some rare occasions; that's for a separate commit.

Differential Revision: http://reviews.llvm.org/D6904


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228325 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 18:31:02 +00:00
Andrew Trick
c4ae8cbc5d X86 ABI fix for return values > 24 bytes.
The return value's address must be returned in %rax.
i.e. the callee needs to copy the sret argument (%rdi)
into the return value (%rax).

This probably won't manifest as a bug when the caller is LLVM-compiled
code. But it is an ABI guarantee and tools expect it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228321 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 18:09:05 +00:00
Sanjay Patel
bf9263158f move fold comments to the corresponding fold; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228317 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 17:33:59 +00:00
Bruno Cardoso Lopes
04715c9915 [X86][MMX] Handle i32->mmx conversion using movd
Implement a BITCAST dag combine to transform i32->mmx conversion patterns
into a X86 specific node (MMX_MOVW2D) and guarantee that moves between
i32 and x86mmx are better handled, i.e., don't use store-load to do the
conversion..

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228293 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 13:23:07 +00:00
Bruno Cardoso Lopes
3b5d8c5d78 [X86][MMX] Move MMX DAG node to proper file
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228291 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 13:22:50 +00:00
Craig Topper
20d15157e4 [X86] Add xrstors/xsavec/xsaves/clflushopt/clwb/pcommit instructions
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228283 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 08:51:06 +00:00
Craig Topper
b8fa51de42 [X86] Remove two feature flags that covered sets of instructions that have no patterns or intrinsics. Since we don't check feature flags in the assembler parser for any instruction sets, these flags don't provide any value. This frees up 2 of the fully utilized feature flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228282 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 08:51:02 +00:00
Larisse Voufo
27fa7bdd07 Disable enumeral mismatch warning when compiling llvm with gcc.
Tested with gcc 4.9.2.
Compiling with -Werror was producing:
.../llvm/lib/Target/X86/X86ISelLowering.cpp: In function 'llvm::SDValue lowerVectorShuffleAsBitMask(llvm::SDLoc, llvm::MVT, llvm::SDValue, llvm::SDValue, llvm::ArrayRef<int>, llvm::SelectionDAG&)':
.../llvm/lib/Target/X86/X86ISelLowering.cpp:7771:40: error: enumeral mismatch in conditional expression: 'llvm::X86ISD::NodeType' vs 'llvm::ISD::NodeType' [-Werror=enum-compare]
   V = DAG.getNode(VT.isFloatingPoint() ? X86ISD::FAND : ISD::AND, DL, VT, V,
                                        ^

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228271 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 04:54:51 +00:00
Chandler Carruth
b0589710cc [x86] Give movss and movsd execution domains in the x86 backend.
This associates movss and movsd with the packed single and packed double
execution domains (resp.). While this is largely cosmetic, as we now
don't have weird ping-pong-ing between single and double precision, it
is also useful because it avoids the domain fixing algorithm from seeing
domain breaks that don't actually exist. It will also be much more
important if we have an execution domain default other than packed
single, as that would cause us to mix movss and movsd with integer
vector code on a regular basis, a very bad mixture.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228135 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 10:58:53 +00:00
Chandler Carruth
da681cc578 [x86] Start to introduce bit-masking based blend lowering.
This is the simplest form of bit-math based blending which only fires
when we are blending with zero and is relatively profitable. I've only
enabled this path on very specific lowering strategies. I'm planning to
widen its applicability in subsequent patches, but so far you'll notice
that even though we get fewer shufps instructions, we *still* do the bit
math in the FP execution port. I'm looking into why this is still
happening.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228124 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 09:06:05 +00:00
Chandler Carruth
5ad147196d [x86] Add missing patterns for andps, orps, xorps, and andnps.
Specifically, the existing patterns were scalar-only. These cover the
packed vector bitwise operations when specifically requested with pseudo
instructions. This is particularly important in SSE1 where we can't
actually emit a logical operation on a v2i64 as that isn't a legal type.

This will be tested in subsequent patches which form the floating point
and patterns in more places.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228123 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 09:06:01 +00:00
Chandler Carruth
2e49ac01a6 [x86] Fix signed vs. unsigned comparison.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228055 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 22:43:30 +00:00
Simon Pilgrim
ae43f39965 Fixed unused variable warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228054 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 22:39:28 +00:00
Simon Pilgrim
3d04e48cb6 [X86][SSE] psrl(w/d/q) and psll(w/d/q) bit shifts for SSE2
Patch to match cases where shuffle masks can be reduced to bit shifts. Similar to byte shift shuffle matching from D5699.

Differential Revision: http://reviews.llvm.org/D6649

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228047 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 21:58:29 +00:00
Simon Pilgrim
4855886269 Fixed signed/unsigned comparison warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228027 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 20:54:01 +00:00
Simon Pilgrim
b559573571 Fixed unused variable warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228025 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 20:38:52 +00:00
Simon Pilgrim
646722d55f [X86][SSE] Added general integer shuffle matching for MOVQ instruction
This patch adds general shuffle pattern matching for the MOVQ zero-extend instruction (copy lower 64bits, zero upper) for all 128-bit integer vectors, it is added as a fallback test in lowerVectorShuffleAsZeroOrAnyExtend.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228022 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 20:09:18 +00:00
Simon Pilgrim
71a4e9522e [X86][AVX2] Enabled shuffle matching for the AVX2 zero extension (128bit -> 256bit) vpmovzx* instructions.
Differential Revision: http://reviews.llvm.org/D7251

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228014 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 19:34:09 +00:00
Sanjay Patel
9b4cc76745 Merge consecutive 16-byte loads into one 32-byte load (PR22329)
This patch detects consecutive vector loads using the existing 
EltsFromConsecutiveLoads() logic. This fixes:
http://llvm.org/bugs/show_bug.cgi?id=22329

This patch effectively reverts the tablegen additions of D6492 / 
http://reviews.llvm.org/rL224344 ...which in hindsight were a horrible hack.

The test cases that were added with that patch are simply modified to load
from varying offsets of a base pointer. These loads did not match the existing
tablegen patterns.

A happy side effect of doing this optimization earlier is that we can now fold
the load into a math op where possible; this is shown in some of the updated
checks in the test file.

Differential Revision: http://reviews.llvm.org/D7303



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228006 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 18:54:00 +00:00
Sanjay Patel
93e763c5cb remove variable names from comments; NFC
I didn't bother to fix the self-referential definitions and grammar
because my eyes started to bleed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228004 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 18:47:32 +00:00
Sanjay Patel
3cf9267d4e Fix program crashes due to alignment exceptions generated for SSE memop instructions (PR22371).
r224330 introduced a bug by misinterpreting the "FeatureVectorUAMem" bit.
The commit log says that change did not affect anything, but that's not correct.
That change allowed SSE instructions to have unaligned mem operands folded into
math ops, and that's not allowed in the default specification for any SSE variant. 

The bug is exposed when compiling for an AVX-capable CPU that had this feature
flag but without enabling AVX codegen. Another mistake in r224330 was not adding
the feature flag to all AVX CPUs; the AMD chips were excluded.

This is part of the fix for PR22371 ( http://llvm.org/bugs/show_bug.cgi?id=22371 ).

This feature bit is SSE-specific, so I've renamed it to "FeatureSSEUnalignedMem".
Changed the existing test case for the feature bit to reflect the new name and
renamed the test file itself to better reflect the feature.
Added runs to fold-vex.ll to check for the failing codegen.

Note that the feature bit is not set by default on any CPU because it may require a
configuration register setting to enable the enhanced unaligned behavior.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227983 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 17:13:04 +00:00
Bruno Cardoso Lopes
7df357f552 [X86][MMX] Improve transfer from mmx to i32
Improve EXTRACT_VECTOR_ELT DAG combine to catch conversion patterns
between x86mmx and i32 with more layers of indirection.

Before:
  movq2dq %mm0, %xmm0
  movd %xmm0, %eax
After:
  movd %mm0, %eax

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227969 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 14:46:49 +00:00
Craig Topper
97494e9718 [X86] Make fxsave64/fxrstor64/xsave64/xsrstor64/xsaveopt64 parseable in AT&T syntax. Also make them the default output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227963 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 11:03:57 +00:00
Craig Topper
c7f2036c2b [X86] Add Requires[In64BitMode] around MOVSX64rr32/MOVSX64rm32. This makes it more strictly mutexed with the ARPL instruction 32-bit mode. Helps with some disassembler changes I'm experimenting with. Should be NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227962 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 11:03:43 +00:00
Eric Christopher
82181dfe51 Migrate to using the subtarget on the machine function and update
all uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227891 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-02 23:03:45 +00:00
Eric Christopher
8115b6b867 Reuse a bunch of cached subtargets and remove getSubtarget calls
without a Function argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227814 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-02 17:38:43 +00:00
Eric Christopher
eb2eaae1af Remove some unused forward declarations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227812 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-02 17:38:37 +00:00
Michael Kuperstein
acd5f13c88 [X86] Convert esp-relative movs of function arguments to pushes, step 2
This moves the transformation introduced in r223757 into a separate MI pass.
This allows it to cover many more cases (not only cases where there must be a 
reserved call frame), and perform rudimentary call folding. It still doesn't 
have a heuristic, so it is enabled only for optsize/minsize, with stack 
alignment <= 8, where it ought to be a fairly clear win.

(Re-commit of r227728)

Differential Revision: http://reviews.llvm.org/D6789


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227752 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 16:56:04 +00:00
Michael Kuperstein
5b61b8f53c Revert r227728 due to bad line endings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227746 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 16:15:07 +00:00
Chandler Carruth
b71d385494 [multiversion] Switch the TTI queries from TargetMachine to Subtarget
now that we have a correct and cached subtarget specific to the
function.

Also, finish providing a cached per-function subtarget in the core
LLVMTargetMachine -- that layer hadn't switched over yet.

The only use of the TargetMachine was to re-lookup a subtarget for
a particular function to work around the fact that TTI was immutable.
Now that it is per-function and we haved a cached subtarget, use it.

This still leaves a few interfaces with real warts on them where we were
passing Function objects through the TTI interface. I'll remove these
and clean their usage up in subsequent commits now that this isn't
necessary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227738 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 14:22:17 +00:00
Chandler Carruth
d0bfb83efb [multiversion] Remove the cached TargetMachine pointer from the
intermediate TTI implementation template and instead query up to the
derived class for both the TargetMachine and the TargetLowering.

Most of the derived types had a TLI cached already and there is no need
to store a less precisely typed target machine pointer.

This will in turn make it much cleaner to look up the TLI via
a per-function subtarget instead of the generic subtarget, and it will
pave the way toward pulling the subtarget used for unroll preferences
into the same form once we are *always* using the function to look up
the correct subtarget.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227737 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 14:01:15 +00:00
Chandler Carruth
6e89e1316a [multiversion] Switch all of the targets over to use the
TargetIRAnalysis access path directly rather than implementing getTTI.

This even removes getTTI from the interface. It's more efficient for
each target to just register a precise callback that creates their
specific TTI.

As part of this, all of the targets which are building their subtargets
individually per-function now build their TTI instance with the function
and thus look up the correct subtarget and cache it. NVPTX, R600, and
XCore currently don't leverage this functionality, but its trivial for
them to add it now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227735 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 13:20:00 +00:00
Chandler Carruth
d12af8754e [multiversion] Remove a false freedom to leave the TargetMachine pointer
null.

For some reason some of the original TTI code supported a null target
machine. This seems to have been legacy, and I made matters worse when
refactoring this code by spreading that pattern further through the
various targets.

The TargetMachine can't actually be null, and it doesn't make sense to
support that use case. I've now consistently removed it and removed all
of the code trying to cope with that situation. This is probably good,
as several targets *didn't* cope with it being null despite the null
default argument in their constructors. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227734 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 12:38:24 +00:00
Michael Kuperstein
59d9986259 [X86] Convert esp-relative movs of function arguments to pushes, step 2
This moves the transformation introduced in r223757 into a separate MI pass.
This allows it to cover many more cases (not only cases where there must be a 
reserved call frame), and perform rudimentary call folding. It still doesn't 
have a heuristic, so it is enabled only for optsize/minsize, with stack 
alignment <= 8, where it ought to be a fairly clear win.

Differential Revision: http://reviews.llvm.org/D6789

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227728 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 11:44:44 +00:00
Craig Topper
270f7a2669 [X86] Add a few target specific nodes to 'getTargetNodeName'
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227720 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 10:00:37 +00:00
Chandler Carruth
685c2add65 [PM] Remove a bunch of stale TTI creation method declarations. I nuked
their definitions, but forgot to clean up all the declarations which are
in different files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227698 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 00:22:15 +00:00
Saleem Abdulrasool
7708f5b68a X86: silence a GCC warning
GCC 4.9 gives the following warning:
  warning: enumeral and non-enumeral type in conditional expression
Cast the enumeral value to an integer within the ternary operation.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227692 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 17:56:11 +00:00
Diego Novillo
96a563ccfa Remove unused variable.
Summary:
This variable is only used inside an assert. This breaks builds with
asserts disabled.

OK for trunk?

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7314

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227691 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 17:17:33 +00:00
Aaron Ballman
2376747a12 Removed a spurious semicolon; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227690 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 15:18:47 +00:00
Simon Pilgrim
4c91d590d5 Removed SSE lane blend findCommutedOpIndices overrides. NFCI.
The default op indices frmo TargetInstrInfo::findCommutedOpIndices are being commuted so we don't need to do this.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227689 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 15:16:30 +00:00
Simon Pilgrim
982005c23e [X86][SSE] Shuffle mask decode support for zero extend, scalar float/double moves and integer load instructions
This patch adds shuffle mask decodes for integer zero extends (pmovzx** and movq xmm,xmm) and scalar float/double loads/moves (movss/movsd).

Also adds shuffle mask decodes for integer loads (movd/movq).

Differential Revision: http://reviews.llvm.org/D7228

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227688 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 14:09:36 +00:00
Chandler Carruth
1937233a22 [PM] Switch the TargetMachine interface from accepting a pass manager
base which it adds a single analysis pass to, to instead return the type
erased TargetTransformInfo object constructed for that TargetMachine.

This removes all of the pass variants for TTI. There is now a single TTI
*pass* in the Analysis layer. All of the Analysis <-> Target
communication is through the TTI's type erased interface itself. While
the diff is large here, it is nothing more that code motion to make
types available in a header file for use in a different source file
within each target.

I've tried to keep all the doxygen comments and file boilerplate in line
with this move, but let me know if I missed anything.

With this in place, the next step to making TTI work with the new pass
manager is to introduce a really simple new-style analysis that produces
a TTI object via a callback into this routine on the target machine.
Once we have that, we'll have the building blocks necessary to accept
a function argument as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227685 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 11:17:59 +00:00
Chandler Carruth
a6a87b595d [PM] Change the core design of the TTI analysis to use a polymorphic
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227669 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 03:43:40 +00:00
Eric Christopher
9003c8d02f Remove the last vestiges of resetOperationActions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227648 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 00:21:17 +00:00