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Commit Graph

492 Commits

Author SHA1 Message Date
Mehdi Amini
17080aa296 Remove getDataLayout() from TargetSelectionDAGInfo (had no users)
Summary:
Remove empty subclass in the process.

This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren, ted

Differential Revision: http://reviews.llvm.org/D11045

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241780
2015-07-09 02:10:08 +00:00
Mehdi Amini
80730bca4b Remove getDataLayout() from TargetLowering
Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: yaron.keren, rafael, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D11042

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241779
2015-07-09 02:09:52 +00:00
Mehdi Amini
761f22ac31 Make isLegalAddressingMode() taking DataLayout as an argument
Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren

Differential Revision: http://reviews.llvm.org/D11040

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241778
2015-07-09 02:09:40 +00:00
Mehdi Amini
547576cef1 Make TargetLowering::getShiftAmountTy() taking DataLayout as an argument
Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren

Differential Revision: http://reviews.llvm.org/D11037

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241776
2015-07-09 02:09:20 +00:00
Mehdi Amini
abf873c623 Make TargetLowering::getPointerTy() taking DataLayout as an argument
Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, ted, yaron.keren, rafael, llvm-commits

Differential Revision: http://reviews.llvm.org/D11028

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241775
2015-07-09 02:09:04 +00:00
Mehdi Amini
8fce925ea2 Make TargetTransformInfo keeping a reference to the Module DataLayout
DataLayout is no longer optional. It was initialized with or without
a DataLayout, and the DataLayout when supplied could have been the
one from the TargetMachine.

Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren

Differential Revision: http://reviews.llvm.org/D11021

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241774
2015-07-09 02:08:42 +00:00
Mehdi Amini
c61d582f14 Redirect DataLayout from TargetMachine to Module in ComputeValueVTs()
Summary:
Avoid using the TargetMachine owned DataLayout and use the Module owned
one instead. This requires passing the DataLayout up the stack to
ComputeValueVTs().

This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, yaron.keren, rafael, llvm-commits

Differential Revision: http://reviews.llvm.org/D11019

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241773
2015-07-09 01:57:34 +00:00
Eli Bendersky
34f1645451 Cosmetic cleanups - NFC
Remove commented lines, trailing whitespace, etc.

llvm-svn: 241687
2015-07-08 16:33:21 +00:00
Daniel Sanders
46f5420293 Change the last few internal StringRef triples into Triple objects.
Summary:
This concludes the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

At this point, the StringRef-form of GNU Triples should only be used in the
public API (including IR serialization) and a couple objects that directly
interact with the API (most notably the Module class). The next step is to
replace these Triple objects with the TargetTuple object that will represent
our authoratative/unambiguous internal equivalent to GNU Triples.

Reviewers: rengolin

Subscribers: llvm-commits, jholewinski, ted, rengolin

Differential Revision: http://reviews.llvm.org/D10962

llvm-svn: 241472
2015-07-06 16:56:07 +00:00
Benjamin Kramer
89b0e53c15 [TargetLowering] StringRefize asm constraint getters.
There is some functional change here because it changes target code from
atoi(3) to StringRef::getAsInteger which has error checking. For valid
constraints there should be no difference.

llvm-svn: 241411
2015-07-05 19:29:18 +00:00
Jingyue Wu
5f36b4cd05 [NVPTX] expand extload/truncstore for vectors of floats
Summary:
According to PTX ISA:

For convenience, ld, st, and cvt instructions permit source and destination data operands to be wider than the instruction-type size, so that narrow values may be loaded, stored, and converted using regular-width registers. For example, 8-bit or 16-bit values may be held directly in 32-bit or 64-bit registers when being loaded, stored, or converted to other types and sizes. The operand type checking rules are relaxed for bit-size and integer (signed and unsigned) instruction types; floating-point instruction types still require that the operand type-size matches exactly, unless the operand is of bit-size type.

So, the ISA does not support load with extending/store with truncatation for floating numbers. This is reflected in setting the loadext/truncstore actions to expand in the code for floating numbers, but vectors of floating numbers are not taken care of.

As a result, loading a vector of floats followed by a fp_extend may be combined by DAGCombiner to a extload, and the extload may be lowered to NVPTXISD::LoadV2 with extending information. However, NVPTXISD::LoadV2 does not perform extending, and no extending instructions are inserted. Finally, PTX instructions with mismatched types are generated, like
ld.v2.f32 {%fd3, %fd4}, [%rd2]

This patch adds the correct actions for vectors of floats, so DAGCombiner would not create loads with extending, and correct code is generated.

Patched by Gang Hu. 

Test Plan: Test case attached.

Reviewers: jingyue

Reviewed By: jingyue

Subscribers: llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D10876

llvm-svn: 241191
2015-07-01 21:32:42 +00:00
Jingyue Wu
bf15de754a [NVPTX] Move NVPTXPeephole after NVPTXPrologEpilogPass
Summary:
Offset of frame index is calculated by NVPTXPrologEpilogPass. Before
that the correct offset of stack objects cannot be obtained, which
leads to wrong offset if there are more than 2 frame objects. This patch
move NVPTXPeephole after NVPTXPrologEpilogPass. Because the frame index
is already replaced by %VRFrame in NVPTXPrologEpilogPass, we check
VRFrame register instead, and try to remove the VRFrame if there
is no usage after NVPTXPeephole pass.

Patched by Xuetian Weng. 

Test Plan:
Strengthened test/CodeGen/NVPTX/local-stack-frame.ll to check the
offset calculation based on SP and SPL.

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10853

llvm-svn: 241185
2015-07-01 20:08:06 +00:00
Jingyue Wu
4759e1d16f [NVPTX] cleanups and refacotring in NVPTXFrameLowering.cpp
Summary: NFC

Test Plan: no regression

Reviewers: wengxt

Reviewed By: wengxt

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10849

llvm-svn: 241118
2015-06-30 21:28:31 +00:00
Jingyue Wu
20fd92cbbc [NVPTX] Fix issue introduced in D10321
Summary:
Really check if %SP is not used in other places, instead of checking only exact
one non-dbg use.

Patched by Xuetian Weng. 

Test Plan:
@foo4 in test/CodeGen/NVPTX/local-stack-frame.ll, create a case that
SP will appear twice.

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: llvm-commits, sfantao, jholewinski

Differential Revision: http://reviews.llvm.org/D10844

llvm-svn: 241099
2015-06-30 18:59:19 +00:00
Samuel Antao
067b1d340e Force relocation mode to be default, regardless of what is passed to the backend.
llvm-svn: 241081
2015-06-30 17:18:00 +00:00
Jingyue Wu
e89c324de3 [NVPTX] noop when kernel pointers are already global
Summary:
Some front ends make kernel pointers global already. In that case,
handlePointerParams does nothing.

Test Plan: more tests in lower-kernel-ptr-arg.ll

Reviewers: grosser

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10779

llvm-svn: 240849
2015-06-26 22:35:43 +00:00
Jingyue Wu
7ff7eb51d2 Add NVPTXPeephole pass to reduce unnecessary address cast
Summary:
This patch first change the register that holds local address for stack
frame to %SPL. Then the new NVPTXPeephole pass will try to scan the
following pattern

   %vreg0<def> = LEA_ADDRi64 <fi#0>, 4
   %vreg1<def> = cvta_to_local %vreg0

and transform it into

   %vreg1<def> = LEA_ADDRi64 %VRFrameLocal, 4

Patched by Xuetian Weng

Test Plan: test/CodeGen/NVPTX/local-stack-frame.ll

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: eliben, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10549

llvm-svn: 240587
2015-06-24 20:20:16 +00:00
Rafael Espindola
72dc307fa0 Simplify the Mangler interface now that DataLayout is mandatory.
We only need to pass in a DataLayout when mangling a raw string, not when
constructing the mangler.

llvm-svn: 240405
2015-06-23 13:59:29 +00:00
Alexander Kornienko
f993659b8f Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Alexander Kornienko
40cb19d802 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Jingyue Wu
34412b317e Add NVPTXLowerAlloca pass to convert alloca'ed memory to local address
Summary:
This is done by first adding two additional instructions to convert the
alloca returned address to local and convert it back to generic. Then
replace all uses of alloca instruction with the converted generic
address. Then we can rely NVPTXFavorNonGenericAddrSpace pass to combine
the generic addresscast and the corresponding Load, Store, Bitcast, GEP
Instruction together.

Patched by Xuetian Weng (xweng@google.com). 

Test Plan: test/CodeGen/NVPTX/lower-alloca.ll

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: meheff, broune, eliben, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10483

llvm-svn: 239964
2015-06-17 22:31:02 +00:00
Daniel Sanders
134c99480b Clean up redundant copies of Triple objects. NFC
Summary:

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10382

llvm-svn: 239823
2015-06-16 15:44:21 +00:00
Daniel Sanders
ac381fec59 Replace string GNU Triples with llvm::Triple in TargetMachine. NFC.
Summary:
For the moment, TargetMachine::getTargetTriple() still returns a StringRef.

This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: ted, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10362

llvm-svn: 239554
2015-06-11 19:41:26 +00:00
Ahmed Bougacha
ee490f0abc [CodeGen] ArrayRef'ize cond/pred in various TII APIs. NFC.
llvm-svn: 239553
2015-06-11 19:30:37 +00:00
Pete Cooper
8328fce315 Remove MachineModuleInfo::UsedFunctions as it has no users.
It hasn't been used since r130964.

This also removes MachineModuleInfo::isUsedFunction and
MachineModuleInfo::AnalyzeModule, both of which were only
there to support UsedFunctions.

llvm-svn: 239501
2015-06-11 01:04:56 +00:00
Daniel Sanders
e37ebd59c5 Replace string GNU Triples with llvm::Triple in MCSubtargetInfo and create*MCSubtargetInfo(). NFC.
Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rafael

Reviewed By: rafael

Subscribers: rafael, ted, jfb, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10311

llvm-svn: 239467
2015-06-10 12:11:26 +00:00
Jingyue Wu
2406860399 [NVPTX] fix a crash bug in NVPTXFavorNonGenericAddrSpaces
Summary:
We used to assume V->RAUW only modifies the operand list of V's user.
However, if V and V's user are Constants, RAUW may replace and invalidate V's
user entirely.

This patch fixes the above issue by letting the caller replace the
operand instead of calling RAUW on Constants.

Test Plan: @nested_const_expr and @rauw in access-non-generic.ll

Reviewers: broune, jholewinski

Reviewed By: broune, jholewinski

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10345

llvm-svn: 239435
2015-06-09 21:50:32 +00:00
Samuel Antao
1e229d55ce The constant initialization for globals in NVPTX is generated as an
array of bytes. The generation of this byte arrays was expecting 
the host to be little endian, which prevents big endian hosts to be 
used in the generation of the PTX code. This patch fixes the 
problem by changing the way the bytes are extracted so that it 
works for either little and big endian.

llvm-svn: 239412
2015-06-09 16:29:34 +00:00
Daniel Sanders
1835a8f945 [nvptx] Only support the 'm' inline assembly memory constraint. NFC.
Summary:
NVPTX doesn't seem to support any additional constraints. Therefore remove
the target hook.

No functional change intended.

Reviewers: jholewinski

Reviewed By: jholewinski

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8209

llvm-svn: 239395
2015-06-09 10:34:05 +00:00
Matt Arsenault
8c9e05929c MC: Add target hook to control symbol quoting
llvm-svn: 239370
2015-06-09 00:31:39 +00:00
Jingyue Wu
c74965ca17 [NVPTX] run SROA after NVPTXFavorNonGenericAddrSpaces
Summary:
This cleans up most allocas NVPTXLowerKernelArgs emits for byval
parameters.

Test Plan: makes bug21465.ll more stronger to verify no redundant local load/store.

Reviewers: eliben, jholewinski

Reviewed By: eliben, jholewinski

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10322

llvm-svn: 239368
2015-06-09 00:05:56 +00:00
Jingyue Wu
efaa872a9c [NVPTX] roll forward r239082
NVPTXISelDAGToDAG translates "addrspacecast to param" to
NVPTX::nvvm_ptr_gen_to_param

Added an llc test in bug21465.

llvm-svn: 239100
2015-06-04 21:28:26 +00:00
Jingyue Wu
aaaab32848 Revert r239082
llc crashed for NVPTX backend

llvm-svn: 239094
2015-06-04 21:07:08 +00:00
Jingyue Wu
98b56fca22 [NVPTX] kernel pointer arguments point to the global address space
Summary:
With this patch, NVPTXLowerKernelArgs converts a kernel pointer argument to a
pointer in the global address space. This change, along with
NVPTXFavorNonGenericAddrSpaces, allows the NVPTX backend to emit ld.global.*
and st.global.* for accessing kernel pointer arguments.

Minor changes:
1. refactor: extract function convertToPointerInAddrSpace
2. fix a bug in the test case in bug21465.ll

Test Plan: lower-kernel-ptr-arg.ll

Reviewers: eliben, meheff, jholewinski

Reviewed By: jholewinski

Subscribers: wengxt, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10154

llvm-svn: 239082
2015-06-04 20:19:38 +00:00
Daniel Sanders
06c811431c Replace string GNU Triples with llvm::Triple in MCAsmInfo subclasses and create*AsmInfo(). NFC.
Summary:
This is the first of several patches to eliminate StringRef forms of GNU
triples from the internals of LLVM. After this is complete, GNU triples
will be replaced by a more authoratitive representation in the form of
an LLVM TargetTuple.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: ted, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10236

llvm-svn: 239036
2015-06-04 13:12:25 +00:00
Benjamin Kramer
9139d0a501 Push constness through LoopInfo::isLoopHeader and clean it up a bit.
NFC.

llvm-svn: 238843
2015-06-02 15:28:27 +00:00
Matt Arsenault
b0334192af Add address space argument to isLegalAddressingMode
This is important because of different addressing modes
depending on the address space for GPU targets.

This only adds the argument, and does not update
any of the uses to provide the correct address space.

llvm-svn: 238723
2015-06-01 05:31:59 +00:00
Jim Grosbach
30efd68a58 MC: Clean up MCExpr naming. NFC.
llvm-svn: 238634
2015-05-30 01:25:56 +00:00
Jingyue Wu
40e406369e [NVPTXFavorNonGenericAddrSpaces] recursively trace into GEP and BitCast
Summary:
This patch allows NVPTXFavorNonGenericAddrSpaces to remove addrspacecast
from longer chains consisting of GEPs and BitCasts. For example, it can
now optimize

  %0 = addrspacecast [10 x float] addrspace(3)* @a to [10 x float]*
  %1 = gep [10 x float]* %0, i64 0, i64 %i
  %2 = bitcast float* %1 to i32*
  %3 = load i32* %2 ; emits ld.u32

to

  %0 = gep [10 x float] addrspace(3)* @a, i64 0, i64 %i
  %1 = bitcast float addrspace(3)* %0 to i32 addrspace(3)*
  %3 = load i32 addrspace(3)* %1 ; emits ld.shared.f32

Test Plan: @ld_int_from_global_float in access-non-generic.ll

Reviewers: broune, eliben, jholewinski, meheff

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10074

llvm-svn: 238574
2015-05-29 17:00:27 +00:00
Benjamin Kramer
5a56e44e39 Don't call utostr in Twine/raw_ostream contexts.
Creating temporary std::strings there is unnecessary.

llvm-svn: 238412
2015-05-28 11:24:24 +00:00
Jingyue Wu
6c391c6619 [NaryReassociate] Run EarlyCSE after NaryReassociate
Summary:
This patch made two improvements to NaryReassociate and the NVPTX pipeline

1. Run EarlyCSE/GVN after NaryReassociate to get rid of redundant common
expressions.

2. When adding an instruction to SeenExprs, maps both the SCEV before and after
reassociation to that instruction.

Test Plan: updated @reassociate_gep_nsw in nary-gep.ll

Reviewers: meheff, broune

Reviewed By: broune

Subscribers: dberlin, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D9947

llvm-svn: 238396
2015-05-28 04:56:52 +00:00
Rafael Espindola
dda3f1317e Move alignment from MCSectionData to MCSection.
This starts merging MCSection and MCSectionData.

There are a few issues with the current split between MCSection and
MCSectionData.

* It optimizes the the not as important case. We want the production
of .o files to be really fast, but the split puts the information used
for .o emission in a separate data structure.

* The ELF/COFF/MachO hierarchy is not represented in MCSectionData,
leading to some ad-hoc ways to represent the various flags.

* It makes it harder to remember where each item is.

The attached patch starts merging the two by moving the alignment from
MCSectionData to MCSection.

Most of the patch is actually just dropping 'const', since
MCSectionData is mutable, but MCSection was not.

llvm-svn: 237936
2015-05-21 19:20:38 +00:00
Jim Grosbach
95c79d189f MC: Clean up method names in MCContext.
The naming was a mish-mash of old and new style. Update to be consistent
with the new. NFC.

llvm-svn: 237594
2015-05-18 18:43:14 +00:00
Pete Cooper
043506dd8f Remove MCAssembler.h include from MCStreamer.h and fix users of MCStreamer.h
llvm-svn: 237483
2015-05-15 22:19:42 +00:00
Pete Cooper
8d13c88def Remove 3 includes from MCInstrDesc.h and explicitly include them where needed
llvm-svn: 237481
2015-05-15 21:58:42 +00:00
Jim Grosbach
0c6b91deee MC: MCCodeGenInfo naming update. NFC.
s/InitMCCodeGenInfo/initMCCodeGenInfo/

llvm-svn: 237471
2015-05-15 19:13:31 +00:00
Jim Grosbach
b635db1046 MC: Modernize MCOperand API naming. NFC.
MCOperand::Create*() methods renamed to MCOperand::create*().

llvm-svn: 237275
2015-05-13 18:37:00 +00:00
Matthias Braun
3b3ecc12b2 Change getTargetNodeName() to produce compiler warnings for missing cases, fix them
llvm-svn: 236775
2015-05-07 21:33:59 +00:00
Quentin Colombet
c82cc9dc57 [ShrinkWrap] Add (a simplified version) of shrink-wrapping.
This patch introduces a new pass that computes the safe point to insert the
prologue and epilogue of the function.
The interest is to find safe points that are cheaper than the entry and exits
blocks.

As an example and to avoid regressions to be introduce, this patch also
implements the required bits to enable the shrink-wrapping pass for AArch64.


** Context **

Currently we insert the prologue and epilogue of the method/function in the
entry and exits blocks. Although this is correct, we can do a better job when
those are not immediately required and insert them at less frequently executed
places.
The job of the shrink-wrapping pass is to identify such places.


** Motivating example **

Let us consider the following function that perform a call only in one branch of
a if:
define i32 @f(i32 %a, i32 %b)  {
 %tmp = alloca i32, align 4
 %tmp2 = icmp slt i32 %a, %b
 br i1 %tmp2, label %true, label %false

true:
 store i32 %a, i32* %tmp, align 4
 %tmp4 = call i32 @doSomething(i32 0, i32* %tmp)
 br label %false

false:
 %tmp.0 = phi i32 [ %tmp4, %true ], [ %a, %0 ]
 ret i32 %tmp.0
}

On AArch64 this code generates (removing the cfi directives to ease
readabilities):
_f:                                     ; @f
; BB#0:
  stp x29, x30, [sp, #-16]!
  mov  x29, sp
  sub sp, sp, #16             ; =16
  cmp  w0, w1
  b.ge  LBB0_2
; BB#1:                                 ; %true
  stur  w0, [x29, #-4]
  sub x1, x29, #4             ; =4
  mov  w0, wzr
  bl  _doSomething
LBB0_2:                                 ; %false
  mov  sp, x29
  ldp x29, x30, [sp], #16
  ret

With shrink-wrapping we could generate:
_f:                                     ; @f
; BB#0:
  cmp  w0, w1
  b.ge  LBB0_2
; BB#1:                                 ; %true
  stp x29, x30, [sp, #-16]!
  mov  x29, sp
  sub sp, sp, #16             ; =16
  stur  w0, [x29, #-4]
  sub x1, x29, #4             ; =4
  mov  w0, wzr
  bl  _doSomething
  add sp, x29, #16            ; =16
  ldp x29, x30, [sp], #16
LBB0_2:                                 ; %false
  ret

Therefore, we would pay the overhead of setting up/destroying the frame only if
we actually do the call.


** Proposed Solution **

This patch introduces a new machine pass that perform the shrink-wrapping
analysis (See the comments at the beginning of ShrinkWrap.cpp for more details).
It then stores the safe save and restore point into the MachineFrameInfo
attached to the MachineFunction.
This information is then used by the PrologEpilogInserter (PEI) to place the
related code at the right place. This pass runs right before the PEI.

Unlike the original paper of Chow from PLDI’88, this implementation of
shrink-wrapping does not use expensive data-flow analysis and does not need hack
to properly avoid frequently executed point. Instead, it relies on dominance and
loop properties.

The pass is off by default and each target can opt-in by setting the
EnableShrinkWrap boolean to true in their derived class of TargetPassConfig.
This setting can also be overwritten on the command line by using
-enable-shrink-wrap.

Before you try out the pass for your target, make sure you properly fix your
emitProlog/emitEpilog/adjustForXXX method to cope with basic blocks that are not
necessarily the entry block.


** Design Decisions **

1. ShrinkWrap is its own pass right now. It could frankly be merged into PEI but
for debugging and clarity I thought it was best to have its own file.
2. Right now, we only support one save point and one restore point. At some
point we can expand this to several save point and restore point, the impacted
component would then be:
- The pass itself: New algorithm needed.
- MachineFrameInfo: Hold a list or set of Save/Restore point instead of one
  pointer.
- PEI: Should loop over the save point and restore point.
Anyhow, at least for this first iteration, I do not believe this is interesting
to support the complex cases. We should revisit that when we motivating
examples.

Differential Revision: http://reviews.llvm.org/D9210

<rdar://problem/3201744>

llvm-svn: 236507
2015-05-05 17:38:16 +00:00
Duncan P. N. Exon Smith
09b5c9c24d IR: Give 'DI' prefix to debug info metadata
Finish off PR23080 by renaming the debug info IR constructs from `MD*`
to `DI*`.  The last of the `DIDescriptor` classes were deleted in
r235356, and the last of the related typedefs removed in r235413, so
this has all baked for about a week.

Note: If you have out-of-tree code (like a frontend), I recommend that
you get everything compiling and tests passing with the *previous*
commit before updating to this one.  It'll be easier to keep track of
what code is using the `DIDescriptor` hierarchy and what you've already
updated, and I think you're extremely unlikely to insert bugs.  YMMV of
course.

Back to *this* commit: I did this using the rename-md-di-nodes.sh
upgrade script I've attached to PR23080 (both code and testcases) and
filtered through clang-format-diff.py.  I edited the tests for
test/Assembler/invalid-generic-debug-node-*.ll by hand since the columns
were off-by-three.  It should work on your out-of-tree testcases (and
code, if you've followed the advice in the previous paragraph).

Some of the tests are in badly named files now (e.g.,
test/Assembler/invalid-mdcompositetype-missing-tag.ll should be
'dicompositetype'); I'll come back and move the files in a follow-up
commit.

llvm-svn: 236120
2015-04-29 16:38:44 +00:00