Commit Graph

7739 Commits

Author SHA1 Message Date
Asiri Rathnayake
bd3e068145 Remove unused function.
Removing an unused function which is causing one of the build bots to fail.
This was introduced in the commit r223113. A proper cleanup of the so_imm
tblgen defintion (made redundant by the mod_imm definition) needs to happen
soon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223115 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-02 12:09:55 +00:00
Asiri Rathnayake
dc05f3a64b Add support for ARM modified-immediate assembly syntax.
Certain ARM instructions accept 32-bit immediate operands encoded as a 8-bit
integer value (0-255) and a 4-bit rotation (0-30, even). Current ARM assembly
syntax support in LLVM allows the decoded (32-bit) immediate to be specified
as a single immediate operand for such instructions:

mov r0, #4278190080

The ARMARM defines an extended assembly syntax allowing the encoding to be made
more explicit, as in:

mov r0, #255, #8 ; (same 32-bit value as above)

The behaviour of the two instructions can be different w.r.t flags, which is
documented under "Modified immediate constants" in ARMARM. This patch enables
support for this extended syntax at the MC layer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223113 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-02 10:53:20 +00:00
Charlie Turner
364f2f3fcf Emit Tag_ABI_FP_denormal correctly in fast-math mode.
The default ARM floating-point mode does not support IEEE 754 mode exactly. Of
relevance to this patch is that input denormals are flushed to zero. The way in
which they're flushed to zero depends on the architecture,

  * For VFPv2, it is implementation defined as to whether the sign of zero is
    preserved.
  * For VFPv3 and above, the sign of zero is always preserved when a denormal
    is flushed to zero.

When FP support has been disabled, the strategy taken by this patch is to
assume the software support will mirror the behaviour of the hardware support
for the target *if it existed*. That is, for architectures which can only have
VFPv2, it is assumed the software will flush to positive zero. For later
architectures it is assumed the software will flush to zero preserving sign.

Change-Id: Icc5928633ba222a4ba3ca8c0df44a440445865fd

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223110 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-02 08:22:29 +00:00
Tim Northover
f7f88095a3 ARM: lower tail calls correctly when using GHC calling convention.
Patch by Ben Gamari.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223055 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 17:46:39 +00:00
Charlie Turner
94df8b11bc Add post-decode checking of HVC instruction.
Add checkDecodedInstruction for post-decode checking of instructions, to catch
the corner cases like HVC that don't fit into the general pattern. Needed to
check for an invalid condition field in instruction encoding despite HVC not
taking a predicate.

Patch by Matthew Wahab.

Change-Id: I48e28de981d7a9e43569594da3c45fb478b4f795

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222992 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 08:50:27 +00:00
Charlie Turner
eed2e8bf98 Add Thumb HVC and ERET virtualisation extension instructions.
Patch by Matthew Wahab.

Change-Id: I131f71c1150d5fa797066a18e09d526c19bf9016

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222990 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 08:39:19 +00:00
Charlie Turner
42563acbd4 Add ARM ERET and HVC virtualisation extension instructions.
Patch by Matthew Wahab.

Change-Id: Iad75f078fbaa4ecc7d7a4820ad9b3930679cbbbb

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222989 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 08:33:28 +00:00
Charlie Turner
3a8b98c984 Fix wrong encoding of MRSBanked.
Patch by Matthew Wahab.

Change-Id: Ia2a001ca2760028ea360fe77b56f203a219eefbc

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222920 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-28 15:01:06 +00:00
Tim Northover
402b6fdf9d Stop using ArrayRef of a const type.
I *think* this is what the GCC bots are complaining about.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222905 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-27 21:29:20 +00:00
Tim Northover
d7a4f74f15 AArch64: treat [N x Ty] as a block during procedure calls.
The AAPCS treats small structs and homogeneous floating (or vector) aggregates
specially, and guarantees they either get passed as a contiguous block of
registers, or prevent any future use of those registers and get passed on the
stack.

This concept can fit quite neatly into LLVM's own type system, mapping an HFA
to [N x float] and so on, and small structs to [N x i64]. Doing so allows
front-ends to emit AAPCS compliant code without having to duplicate the
register counting logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222903 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-27 21:02:42 +00:00
Charlie Turner
72ba1af89c Stop uppercasing build attribute data.
The string data for string-valued build attributes were being unconditionally
uppercased. There is no mention in the ARM ABI addenda about case conventions,
so it's technically implementation defined as to whether the data are
capitialised in some way or not. However, there are good reasons not to
captialise the data.

  * It's less work.
  * Some vendors may legitimately have case-sensitive checks for these
    attributes which would fail on LLVM generated object files.
  * There could be locale issues with uppercasing.

The original reasons for uppercasing appear to have stemmed from an
old codesourcery toolchain behaviour, see

http://comments.gmane.org/gmane.comp.compilers.llvm.cvs/87133

This patch makes the object file emitted no longer captialise string
data, it encodes as seen in the assembly source.

Change-Id: Ibe20dd6e60d2773d57ff72a78470839033aa5538

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222882 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-27 12:13:56 +00:00
Craig Topper
c0dae440e6 Replace neverHasSideEffects=1 with hasSideEffects=0 in all .td files.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222801 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-26 00:46:26 +00:00
Simon Pilgrim
53a43d38df Tidied up target triple OS detection. NFC
Use Triple::isOS*() helper functions where possible.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222622 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-22 19:12:10 +00:00
Joerg Sonnenberger
0b1407b5cf Fix transformation of add with pc argument to adr for non-immediate
arguments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222587 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-21 22:39:34 +00:00
Craig Topper
e0ed7df6b0 Remove a bunch of unnecessary typecasts to 'const TargetRegisterClass *'
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222509 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-21 05:58:21 +00:00
Reid Kleckner
9c390888f7 Fix more instances of -Wsentinel on Windows with s/NULL/nullptr/
Follow up to r221940, where I must not have caught em all. NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222481 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-20 23:51:47 +00:00
Reid Kleckner
d12434058d Add out of line virtual destructors to all LLVMTargetMachine subclasses
These recently all grew a unique_ptr<TargetLoweringObjectFile> member in
r221878.  When anyone calls a virtual method of a class, clang-cl
requires all virtual methods to be semantically valid. This includes the
implicit virtual destructor, which triggers instantiation of the
unique_ptr destructor, which fails because the type being deleted is
incomplete.

This is just part of the ongoing saga of PR20337, which is affecting
Blink as well. Because the MSVC ABI doesn't have key functions, we end
up referencing the vtable and implicit destructor on any virtual call
through a class. We don't actually end up emitting the dtor, so it'd be
good if we could avoid this unneeded type completion work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222480 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-20 23:37:18 +00:00
Jyoti Allur
dc0b300304 [ELF] Prevent ARM ELF object writer from generating deprecated relocation code R_ARM_PLT32
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222414 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-20 05:58:11 +00:00
David Blaikie
5401ba7099 Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool>
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.

This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222334 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-19 07:49:26 +00:00
David Blaikie
1d4f28c6bc Remove StringMap::GetOrCreateValue in favor of StringMap::insert
Having two ways to do this doesn't seem terribly helpful and
consistently using the insert version (which we already has) seems like
it'll make the code easier to understand to anyone working with standard
data structures. (I also updated many references to the Entry's
key and value to use first() and second instead of getKey{Data,Length,}
and get/setValue - for similar consistency)

Also removes the GetOrCreateValue functions so there's less surface area
to StringMap to fix/improve/change/accommodate move semantics, etc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222319 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-19 05:49:42 +00:00
Reid Kleckner
8083adcaca Revert "ADT: correctly report isMSVCEnvironment for windows itanium"
This reverts commit r222180.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222188 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-17 22:55:59 +00:00
Saleem Abdulrasool
2bd09db07f ADT: correctly report isMSVCEnvironment for windows itanium
The itanium environment on Windows uses MSVC and is a MSVC environment.  Report
this correctly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222180 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-17 22:13:26 +00:00
Oliver Stannard
8f832fce3b [Thumb1] Re-write emitThumbRegPlusImmediate
This was motivated by a bug which caused code like this to be
miscompiled:
  declare void @take_ptr(i8*)
  define void @test() {
    %addr1.32 = alloca i8
    %addr2.32 = alloca i32, i32 1028
    call void @take_ptr(i8* %addr1)
    ret void
  }

This was emitting the following assembly to get the value of %addr1:
  add r0, sp, #1020
  add r0, r0, #8
However, "add r0, r0, #8" is not a valid Thumb1 instruction, and this
could not be assembled. The generated object file contained this,
resulting in r0 holding SP+8 rather tha SP+1028:
  add r0, sp, #1020
  add r0, sp, #8

This function looked like it could have caused miscompilations for
other combinations of registers and offsets (though I don't think it is
currently called with these), and the heuristic it used did not match
the emitted code in all cases.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222125 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-17 11:18:10 +00:00
Tim Northover
52e76186d3 ARM: refactor .cfi_def_cfa_offset emission.
We use to track quite a few "adjusted" offsets through the FrameLowering code
to account for changes in the prologue instructions as we went and allow the
emission of correct CFA annotations. However, we were missing a couple of cases
and the code was almost impenetrable.

It's easier to just add any stack-adjusting instruction to a list and emit them
together.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222057 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-14 22:45:33 +00:00
Tim Northover
d96893fd3d ARM: correctly calculate the offset of FP in its push.
When we folded the DPR alignment gap into a push, we weren't noting the extra
distance from the beginning of the push to the FP, and so FP ended up pointing
at an incorrect offset.

The .cfi_def_cfa_offset directives are still wrong in this case, but I think
that can be improved by refactoring.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222056 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-14 22:45:31 +00:00
Aditya Nandakumar
365df40768 We can get the TLOF from the TargetMachine - so constructor no longer requires TargetLoweringObjectFile to be passed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221926 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 21:29:21 +00:00
Tim Northover
8bca5de6a9 ARM: allow constpool entry to be moved to the user's block in all cases.
Normally entries can only move to a lower address, but when that wasn't viable,
the user's block was considered anyway. Unfortunately, it went via
createNewWater which wasn't designed to handle the case where there's already
an island after the block.

Unfortunately, the test we have is slow and fragile, and I couldn't reduce it
to anything sane even with the @llvm.arm.space intrinsic. The test change here
is recreating the previous one after the change.

rdar://problem/18545506

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221905 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 17:58:53 +00:00
Tim Northover
064da63fcb ARM: avoid duplicating branches during constant islands.
We were using a naive heuristic to determine whether a basic block already had
an unconditional branch at the end. This mostly corresponded to reality
(assuming branches got optimised) because there's not much point in a branch to
the next block, but could go wrong.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221904 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 17:58:51 +00:00
Tim Northover
5bd311bf17 ARM: add @llvm.arm.space intrinsic for testing ConstantIslands.
Creating tests for the ConstantIslands pass is very difficult, since it depends
on precise layout details. Having the ability to precisely inject a number of
bytes into the stream helps greatly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221903 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 17:58:48 +00:00
Aditya Nandakumar
847729d19a This patch changes the ownership of TLOF from TargetLoweringBase to TargetMachine so that different subtargets could share the TLOF effectively
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221878 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 09:26:31 +00:00
Rafael Espindola
6a222ec893 Pass an ArrayRef to MCDisassembler::getInstruction.
With this patch MCDisassembler::getInstruction takes an ArrayRef<uint8_t>
instead of a MemoryObject.

Even on X86 there is a maximum size an instruction can have. Given
that, it seems way simpler and more efficient to just pass an ArrayRef
to the disassembler instead of a MemoryObject and have it do a virtual
call every time it wants some extra bytes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221751 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-12 02:04:27 +00:00
Tom Roeder
63dea2c952 Add Forward Control-Flow Integrity.
This commit adds a new pass that can inject checks before indirect calls to
make sure that these calls target known locations. It supports three types of
checks and, at compile time, it can take the name of a custom function to call
when an indirect call check fails. The default failure function ignores the
error and continues.

This pass incidentally moves the function JumpInstrTables::transformType from
private to public and makes it static (with a new argument that specifies the
table type to use); this is so that the CFI code can transform function types
at call sites to determine which jump-instruction table to use for the check at
that site.

Also, this removes support for jumptables in ARM, pending further performance
analysis and discussion.

Review: http://reviews.llvm.org/D4167



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221708 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 21:08:02 +00:00
Rafael Espindola
9272305648 MCAsmParserExtension has a copy of the MCAsmParser. Use it.
Base classes were storing a second copy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221667 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 05:18:41 +00:00
Rafael Espindola
d342c4c748 Misc style fixes. NFC.
This fixes a few cases of:

* Wrong variable name style.
* Lines longer than 80 columns.
* Repeated names in comments.
* clang-format of the above.

This make the next patch a lot easier to read.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221615 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-10 18:11:10 +00:00
Tilmann Scheller
463e275e3e [ARM] Remove more dead code.
Dead code identified by the Clang static analyzer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221372 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 17:45:04 +00:00
Tilmann Scheller
4929a03d42 [ARM] Remove another redundant assignment.
Found by the Clang static analyzer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221368 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 17:34:04 +00:00
Tilmann Scheller
8e4d0d84a0 [ARM] Remove redundant assignment.
Found by the Clang static analyzer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221366 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 17:28:19 +00:00
Tilmann Scheller
33ccf8e66c [ARM] Remove dead code identified by the Clang static analyzer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221358 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 17:10:43 +00:00
Oliver Stannard
382f7d717c [ARM] Honor FeatureD16 in the assembler and disassembler
Some ARM FPUs only have 16 double-precision registers, rather than the
normal 32. LLVM represents this with the D16 target feature. This is
currently used by CodeGen to avoid using high registers when they are
not available, but the assembler and disassembler do not.

I fix this in the assmebler and disassembler rather than the
InstrInfo.td files, as the latter would require a large number of
changes everywhere one of the floating-point instructions is referenced
in the backend. This solution is similar to the one used for
co-processor numbers and MSR masks.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221341 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 12:06:39 +00:00
Tim Northover
cafa378fe0 ARM: try to add extra CS-register whenever stack alignment >= 8.
We currently try to push an even number of registers to preserve 8-byte
alignment during a function's prologue, but only when the stack alignment is
prcisely 8. Many of the reasons for doing it apply also when that alignment > 8
(the extra store is often free, and can save another stack adjustment, though
less frequently for 16-byte stack alignment).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221321 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 00:27:20 +00:00
Tim Northover
1f771b80c0 ARM/Dwarf: correctly align stack before callee-saved VPRs
We were making an attempt to do this by adding an extra callee-saved GPR (so
that there was an even number in the list), but when that failed we went ahead
and pushed anyway.

This had a couple of potential issues:
  + The .cfi directives we emit misplaced dN because they were based on
    PrologEpilogInserter's calculation.
  + Unaligned stores can be less efficient.
  + Unaligned stores can actually fault (likely only an issue in niche cases,
    but possible).

This adds a final explicit stack adjustment if all other options fail, so that
the actual locations of the registers match up with where they should be.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221320 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 00:27:13 +00:00
Akira Hatanaka
8d7cc6b0ff [ARM, inline-asm] Fix ARMTargetLowering::getRegForInlineAsmConstraint to return
register class tGPRRegClass if the target is thumb1.

This commit fixes a crash that occurs during register allocation which was
triggered when a virtual register defined by an inline-asm instruction had to
be spilled.
 
rdar://problem/18740489


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221178 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 20:37:04 +00:00
Charlie Turner
c3606b6b2e Remove the cortex-a9-mp CPU.
This CPU definition is redundant. The Cortex-A9 is defined as
supporting multiprocessing extensions. Remove its definition and
update appropriate tests.

LLVM defines both a cortex-a9 CPU and a cortex-a9-mp CPU. The only
difference between the two CPU definitions in ARM.td is that
cortex-a9-mp contains the feature FeatureMP for multiprocessing
extensions.

This is redundant since the Cortex-A9 is defined as having
multiprocessing extensions in the TRMs. armcc also defines the
Cortex-A9 as having multiprocessing extensions by default.

Change-Id: Ifcadaa6c322be0a33d9d2a39cfdd7da1d75981a7

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221166 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 17:38:00 +00:00
Daniel Sanders
cfe761c9e6 Renamed CCState members that appear to misspell 'Processed' as 'Proceed'. NFC.
Reviewers: rnk

Reviewed By: rnk

Subscribers: rnk, llvm-commits

Differential Revision: http://reviews.llvm.org/D5978

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221061 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-01 19:32:23 +00:00
Rafael Espindola
5793838fc8 Remove redundant calls to isMaterializable.
This removes calls to isMaterializable in the following cases:

* It was redundant with a call to isDeclaration now that isDeclaration returns
  the correct answer for materializable functions.
* It was followed by a call to Materialize. Just call Materialize and check EC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221050 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-01 16:46:18 +00:00
Reid Kleckner
e1a4787d5d Work around bugs in MSVC "14" CTP 3's conversion logic
It appears to ignore or find ambiguous MachineInstrBuilder's conversion
operators that allow conversion to MachineInstr* and
MachineBasicBlock::bundle_iterator.

As a workaround, add an explicit way to get the MachineInstr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221017 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-31 23:19:46 +00:00
Quentin Colombet
9b6ca9304c [CodeGenPrepare] Move extractelement close to store if they can be combined.
This patch adds an optimization in CodeGenPrepare to move an extractelement
right before a store when the target can combine them.
The optimization may promote any scalar operations to vector operations in the
way to make that possible.


** Context **

Some targets use different register files for both vector and scalar operations.
This means that transitioning from one domain to another may incur copy from one
register file to another. These copies are not coalescable and may be expensive.
For example, according to the scheduling model, on cortex-A8 a vector to GPR
move is 20 cycles.


** Motivating Example **

Let us consider an example:
define void @foo(<2 x i32>* %addr1, i32* %dest) {
 %in1 = load <2 x i32>* %addr1, align 8
 %extract = extractelement <2 x i32> %in1, i32 1
 %out = or i32 %extract, 1
 store i32 %out, i32* %dest, align 4
 ret void
}

As it is, this IR generates the following assembly on armv7:
  vldr  d16, [r0]            @vector load  
  vmov.32 r0, d16[1]  @ cross-register-file copy: 20 cycles
  orr r0, r0, #1           @ scalar bitwise or
  str r0, [r1]               @ scalar store
  bx  lr

Whereas we could generate much faster code:
  vldr  d16, [r0]               @ vector load
  vorr.i32  d16, #0x1     @ vector bitwise or
  vst1.32 {d16[1]}, [r1:32] @ vector extract + store
  bx  lr

Half of the computation made in the vector is useless, but this allows to get
rid of the expensive cross-register-file copy.


** Proposed Solution **

To avoid this cross-register-copy penalty, we promote the scalar operations to
vector operations. The penalty will be removed if we manage to promote the whole
chain of computation in the vector domain.
Currently, we do that only when the chain of computation ends by a store and the
target is able to combine an extract with a store.

Stores are the most likely candidates, because other instructions produce values
that would need to be promoted and so, extracted as some point[1]. Moreover,
this is customary that targets feature stores that perform a vector extract (see
AArch64 and X86 for instance).

The proposed implementation relies on the TargetTransformInfo to decide whether
or not it is beneficial to promote a chain of computation in the vector domain.
Unfortunately, this interface is rather inaccurate for this level of details and
although this optimization may be beneficial for X86 and AArch64, the inaccuracy
will lead to the optimization being too aggressive.
Basically in TargetTransformInfo, everything that is legal has a cost of 1,
whereas, even if a vector type is legal, usually a vector operation is slightly
more expensive than its scalar counterpart. That will lead to too many
promotions that may not be counter balanced by the saving of the
cross-register-file copy. For instance, on AArch64 this penalty is just 4
cycles.

For now, the optimization is just enabled for ARM prior than v8, since those
processors have a larger penalty on cross-register-file copies, and the scope is
limited to basic blocks. Because of these two factors, we limit the effects of
the inaccuracy. Indeed, I did not want to build up a fancy cost model with block
frequency and everything on top of that.

[1] We can imagine targets that can combine an extractelement with  other
instructions than just stores. If we want to go into that direction, the current
interfaces must be augmented and, moreover, I think this becomes a global isel
problem.

Differential Revision: http://reviews.llvm.org/D5921

<rdar://problem/14170854>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220978 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-31 17:52:53 +00:00
Oliver Stannard
b1d8e7e77c [ARM] Select VMAXNM and VMINNM regardless of operand order
Currently, the ARM backend will select the VMAXNM and VMINNM for these C
expressions:
  (a < b) ? a : b
  (a > b) ? a : b
but not these expressions:
  (a > b) ? b : a
  (a < b) ? b : a

This patch allows all of these expressions to be matched.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220671 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-27 09:23:02 +00:00
Renato Golin
06b11e36e5 Do not emit intermediate register for zero FP immediate
This updates check for double precision zero floating point constant to allow
use of instruction with immediate value rather than temporary register.
Currently "a == 0.0", where "a" is of "double" type generates:

vmov.i32        d16, #0x0
vcmpe.f64       d0, d16

With this change it becomes:

vcmpe.f64        d0, #0

Patch by Sergey Dmitrouk.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220486 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 15:31:50 +00:00
Oliver Stannard
9982879c4e [Thumb2] Improve disassembly of memory hints
Currently, the ARM disassembler will disassemble the Thumb2 memory hint
instructions (PLD, PLDW and PLI), even for targets which do not have
these instructions. This patch adds the required checks to the
disassmebler.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220472 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 08:52:58 +00:00