1205 Commits

Author SHA1 Message Date
Nemanja Ivanovic
35b282e0ac [PowerPC] Ensure displacements for DQ-Form instructions are multiples of 16
As outlined in the PR, we didn't ensure that displacements for DQ-Form
instructions are multiples of 16. Since the instruction encoding encodes
a quad-word displacement, a sub-16 byte displacement is meaningless and
ends up being encoded incorrectly.

Fixes https://bugs.llvm.org/show_bug.cgi?id=33671.

Differential Revision: https://reviews.llvm.org/D35007


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307934 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-13 18:17:10 +00:00
Tony Jiang
dc4a67cca0 [PPC CodeGen] Expand the bitreverse.i64 intrinsic.
Differential Revision: https://reviews.llvm.org/D34908
Fix PR: https://bugs.llvm.org/show_bug.cgi?id=33093

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307563 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-10 18:11:23 +00:00
Lei Huang
b6988767a8 [PowerPC] Reduce register pressure by not materializing a constant just for use as an index register for X-Form loads/stores.
For this example:
float test (int *arr) {
    return arr[2];
}

We currently generate the following code:
  li r4, 8
  lxsiwax f0, r3, r4
  xscvsxdsp f1, f0

With this patch, we will now generate:
  addi r3, r3, 8
  lxsiwax f0, 0, r3
  xscvsxdsp f1, f0

Originally reported in: https://bugs.llvm.org/show_bug.cgi?id=27204
Differential Revision: https://reviews.llvm.org/D35027

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307553 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-10 16:44:45 +00:00
Hiroshi Inoue
58d2b3aa33 fix typos in comments and error messages; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307533 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-10 12:44:25 +00:00
Lei Huang
36381776b0 [PowerPC] NFC : Common up definitions of isIntS16Immediate and update parameter to int16_t
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307442 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-07 21:12:35 +00:00
Tony Jiang
9163803bf0 [PPC CodeGen] Expand the bitreverse.i32 intrinsic.
Differential Revision: https://reviews.llvm.org/D33572
Fix PR: https://bugs.llvm.org/show_bug.cgi?id=33093

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307413 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-07 16:41:55 +00:00
Simon Pilgrim
daa5b43a38 [PowerPC] Fix -Wimplicit-fallthrough warnings. NFCI.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307382 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-07 10:21:44 +00:00
Tony Jiang
ee1d801b4f [Power9] Exploit vector integer extend instructions when indices aren't correct.
This patch adds on to the exploitation added by https://reviews.llvm.org/D33510.
This now catches build vector nodes where the inputs are coming from sign
extended vector extract elements where the indices used by the vector extract
are not correct. We can still use the new hardware instructions by adding a
shuffle to move the elements to the correct indices. I introduced a new PPCISD
node here because adding a vector_shuffle and changing the elements of the
vector_extracts was getting undone by another DAG combine.

Commit on behalf of Zaara Syeda (syzaara@ca.ibm.com)
Differential Revision: https://reviews.llvm.org/D34009

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307169 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-05 16:00:38 +00:00
Eric Christopher
7eaaf7b8d0 Tidy up some calls to getRegister for readability.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305626 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-17 02:25:49 +00:00
Lei Huang
43be377dc0 Test commit - NFC.
Modified a comment to confirm commit access functionality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305402 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-14 17:25:55 +00:00
Kit Barton
424a297fc0 Test commit - NFC.
Modified a comment to confirm commit access functionality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305309 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-13 17:35:29 +00:00
NAKAMURA Takumi
9dab15d6d6 PPCISelLowering.cpp: Fix warnings in r305214. [-Wdocumentation]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305277 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-13 07:34:32 +00:00
Tony Jiang
759cec2ab3 [PowerPC] Match vec_revb builtins to P9 instructions.
Power9 has instructions that will reverse the bytes within an element for all
sizes (half-word, word, double-word and quad-word). These can be used for the
vec_revb builtins in altivec.h. However, we implement these to match vector
shuffle nodes as that will cover both the builtins and vector shuffles that
occur in the SDAG through other means.

Differential Revision: https://reviews.llvm.org/D33690

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305214 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-12 18:24:36 +00:00
Tony Jiang
e3ae196e24 [Power9] Added support for the modsw, moduw, modsd, modud hardware instructions.
Note that if we need the result of both the divide and the modulo then we
compute the modulo based on the result of the divide and not using the new
hardware instruction.

Commit on behalf of STEFAN PINTILIE.
Differential Revision: https://reviews.llvm.org/D33940

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305210 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-12 17:58:42 +00:00
Sanjay Patel
98a050b9c0 [DAG] add helper to bind memop chains; NFCI
This step is just intended to reduce code duplication rather than change any functionality.

A follow-up would be to replace PPCTargetLowering::spliceIntoChain() usage with this new helper.

Differential Revision: https://reviews.llvm.org/D33649


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305192 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-12 14:41:48 +00:00
Chandler Carruth
e3e43d9d57 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304787 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-06 11:49:48 +00:00
Zaara Syeda
682f92f568 [PPC] Inline expansion of memcmp
This patch does an inline expansion of memcmp.
It changes the memcmp library call into an inline expansion when the size is
known at compile time and is under a target specified threshold.
This expansion is implemented in CodeGenPrepare and expands into straight line
code. The target specifies a maximum load size and the expansion works by using
this size to load the two sources, compare, and exit early if a difference is
found. It also has a special case when the memcmp result is used in a compare
to zero equality.

Differential Revision: https://reviews.llvm.org/D28637

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304313 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-31 17:12:38 +00:00
Tony Jiang
a688c8eaae [PowerPC] Fix a performance bug for PPC::XXPERMDI.
There are some VectorShuffle Nodes in SDAG which can be selected to XXPERMDI
Instruction, this patch recognizes them and does the selection to improve
the PPC performance.

Differential Revision: https://reviews.llvm.org/D33404

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304298 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-31 13:09:57 +00:00
Craig Topper
384602a9e4 [SelectionDAG] Set ISD::FPOWI to Expand by default
Summary:
Currently FPOWI defaults to Legal and LegalizeDAG.cpp turns Legal into Expand for this opcode because Legal is a "lie".

This patch changes the default for this opcode to Expand and removes the hack from LegalizeDAG.cpp. It also removes all the code in the targets that set this opcode to Expand themselves since they can just rely on the default.

Reviewers: spatel, RKSimon, efriedma

Reviewed By: RKSimon

Subscribers: jfb, dschuff, sbc100, jgravelle-google, nemanjai, javed.absar, andrew.w.kaylor, llvm-commits

Differential Revision: https://reviews.llvm.org/D33530

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304215 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-30 15:27:55 +00:00
Tim Shen
5a4717aaf1 [PPC] Add text for assert.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303940 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-25 23:40:46 +00:00
Tim Shen
7a45750233 [PPC] Fix atomics lowering in DAG lowering.
I forgot to forward the chain, causing some missing instruction
dependencies. The test crashes the compiler without this patch.

Inspired by the test case, D33519 also tries to remove the extra sync.

Differential Revision: https://reviews.llvm.org/D33573

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303931 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-25 22:58:35 +00:00
Tony Jiang
133fa95ca7 [PowerPC] Fix a performance bug for PPC::XXSLDWI.
There are some VectorShuffle Nodes in SDAG which can be selected to XXSLDWI
instruction, this patch recognizes them and does the selection to improve the
PPC performance.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303822 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-24 23:48:29 +00:00
Kyle Butt
011a826e4f CodeGen: Power: Add lowering for shifts of v1i128.
When legalizing vector operations on vNi128, they will be split to v1i128
because that is a legal type on ppc64, but then the compiler will crash in
selection dag because it fails to select for these operations. This patch fixes
shift operations. Logical shift right and left shift can be performed in the
vector unit, but algebraic shift right requires being split.

Differential Revision: https://reviews.llvm.org/D32774

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303307 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-17 21:54:41 +00:00
Tim Shen
1a2e7acb99 [PPC] Lower load acquire/seq_cst trailing fence to cmp + bne + isync.
Summary:
This fixes pr32392.

The lowering pipeline is:
llvm.ppc.cfence in IR -> PPC::CFENCE8 in isel -> Actual instructions in
expandPostRAPseudo.

The reason why expandPostRAPseudo is chosen is because previous passes
are likely eliminating instructions like cmpw 3, 3 (early CSE) and bne-
7, .+4 (some branch pass(s)).

Differential Revision: https://reviews.llvm.org/D32763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303205 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-16 20:18:06 +00:00
Tim Shen
ac2d13ffb3 [PPC] Move the combine "a << (b % (sizeof(a) * 8)) -> (PPCshl a, b)" to the backend. NFC.
Summary:
Eli pointed out that it's unsafe to combine the shifts to ISD::SHL etc.,
because those are not defined for b > sizeof(a) * 8, even after some of
the combiners run.

However, PPCISD::SHL defines that behavior (as the instructions themselves).
Move the combination to the backend.

The tests in shift_mask.ll still pass.

Reviewers: echristo, hfinkel, efriedma, iteratee

Subscribers: nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D33076

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302937 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-12 19:25:37 +00:00
Tim Shen
f52671da9b [Atomic] Remove IsStore/IsLoad in the interface, and pass the instruction instead. NFC.
Now both emitLeadingFence and emitTrailingFence take the instruction
itself, instead of taking IsLoad/IsStore pairs.
Instruction::mayReadFromMemory and Instrucion::mayWriteToMemory are used
for determining those two booleans.

The instruction argument is also useful for later D32763, in
emitTrailingFence. For emitLeadingFence, it seems to have cleaner
interface with the proposed change.

Differential Revision: https://reviews.llvm.org/D32762

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302539 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-09 15:27:17 +00:00
Serge Pavlov
1f4a80fdc1 Add extra operand to CALLSEQ_START to keep frame part set up previously
Using arguments with attribute inalloca creates problems for verification
of machine representation. This attribute instructs the backend that the
argument is prepared in stack prior to  CALLSEQ_START..CALLSEQ_END
sequence (see http://llvm.org/docs/InAlloca.htm for details). Frame size
stored in CALLSEQ_START in this case does not count the size of this
argument. However CALLSEQ_END still keeps total frame size, as caller can
be responsible for cleanup of entire frame. So CALLSEQ_START and
CALLSEQ_END keep different frame size and the difference is treated by
MachineVerifier as stack error. Currently there is no way to distinguish
this case from actual errors.

This patch adds additional argument to CALLSEQ_START and its
target-specific counterparts to keep size of stack that is set up prior to
the call frame sequence. This argument allows MachineVerifier to calculate
actual frame size associated with frame setup instruction and correctly
process the case of inalloca arguments.

The changes made by the patch are:
- Frame setup instructions get the second mandatory argument. It
  affects all targets that use frame pseudo instructions and touched many
  files although the changes are uniform.
- Access to frame properties are implemented using special instructions
  rather than calls getOperand(N).getImm(). For X86 and ARM such
  replacement was made previously.
- Changes that reflect appearance of additional argument of frame setup
  instruction. These involve proper instruction initialization and
  methods that access instruction arguments.
- MachineVerifier retrieves frame size using method, which reports sum of
  frame parts initialized inside frame instruction pair and outside it.

The patch implements approach proposed by Quentin Colombet in
https://bugs.llvm.org/show_bug.cgi?id=27481#c1.
It fixes 9 tests failed with machine verifier enabled and listed
in PR27481.

Differential Revision: https://reviews.llvm.org/D32394


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302527 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-09 13:35:13 +00:00
Craig Topper
ace8b39f82 [KnownBits] Add wrapper methods for setting and clear all bits in the underlying APInts in KnownBits.
This adds routines for reseting KnownBits to unknown, making the value all zeros or all ones. It also adds methods for querying if the value is zero, all ones or unknown.

Differential Revision: https://reviews.llvm.org/D32637

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302262 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-05 17:36:09 +00:00
Nemanja Ivanovic
ff5dd4527f [PowerPC] Emit VMX loads/stores for aligned ops to avoid adding swaps on LE
Fixes PR30730.
This is a re-commit of a pulled commit. The commit was pulled because some
software projects contained uses of Altivec vectors that violated alignment
requirements. Known issues have now been fixed.

Committing on behalf of Lei Huang.

Differential Revision: https://reviews.llvm.org/D26861


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301892 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-02 01:47:34 +00:00
Amara Emerson
195d3fa988 Generalize the specialized flag-carrying SDNodes by moving flags into SDNode.
This removes BinaryWithFlagsSDNode, and flags are now all passed by value.

Differential Revision: https://reviews.llvm.org/D32527



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301803 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-01 15:17:51 +00:00
Craig Topper
8b430f87e6 [SelectionDAG] Use KnownBits struct in DAG's computeKnownBits and simplifyDemandedBits
This patch replaces the separate APInts for KnownZero/KnownOne with a single KnownBits struct. This is similar to what was done to ValueTracking's version recently.

This is largely a mechanical transformation from KnownZero to Known.Zero.

Differential Revision: https://reviews.llvm.org/D32569

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301620 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-28 05:31:46 +00:00
Krzysztof Parzyszek
f3b0bf3070 Move value type list from TargetRegisterClass to TargetRegisterInfo
Differential Revision: https://reviews.llvm.org/D31937


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301234 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-24 19:51:12 +00:00
Krzysztof Parzyszek
031e2c7f67 Revert r301231: Accidentally committed stale files
I forgot to commit local changes before commit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301232 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-24 19:48:51 +00:00
Krzysztof Parzyszek
a23ad66819 Move value type list from TargetRegisterClass to TargetRegisterInfo
Differential Revision: https://reviews.llvm.org/D31937


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301231 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-24 19:43:45 +00:00
Simon Pilgrim
07898901df [DAGCombiner] Add vector demanded elements support to computeKnownBitsForTargetNode
Follow up to D25691, this sets up the plumbing necessary to support vector demanded elements support in known bits calculations in target nodes.

Differential Revision: https://reviews.llvm.org/D31249

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299201 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-31 11:24:16 +00:00
Eric Christopher
193628a590 Kill some trailing whitespace to make some new changes a bit easier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298637 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-23 19:41:10 +00:00
Nirav Dave
11fdc7845a Make library calls sensitive to regparm module flag (Fixes PR3997).
Reviewers: mkuper, rnk

Subscribers: mehdi_amini, jyknight, aemerson, llvm-commits, rengolin

Differential Revision: https://reviews.llvm.org/D27050

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298179 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-18 00:44:07 +00:00
Reid Kleckner
1c19be8a98 Remove getArgumentList() in favor of arg_begin(), args(), etc
Users often call getArgumentList().size(), which is a linear way to get
the number of function arguments. arg_size(), on the other hand, is
constant time.

In general, the fact that arguments are stored in an iplist is an
implementation detail, so I've removed it from the Function interface
and moved all other users to the argument container APIs (arg_begin(),
arg_end(), args(), arg_size()).

Reviewed By: chandlerc

Differential Revision: https://reviews.llvm.org/D31052

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298010 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-16 22:59:15 +00:00
Hiroshi Inoue
a2d20c4bca Test commit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297959 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-16 16:30:06 +00:00
Tim Shen
2aec349a25 Revert "Revert "[PowerPC][ELFv2ABI] Allocate parameter area on-demand to reduce stack frame size""
After inspection, it's an UB in our code base. Someone cast a var-arg
function pointer to a non-var-arg one. :/

Re-commit r296771 to continue testing on the patch.

Sorry for the trouble!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297256 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-08 02:41:35 +00:00
Tim Shen
107e5edeba Revert "[PowerPC][ELFv2ABI] Allocate parameter area on-demand to reduce stack frame size"
This reverts commit r296771.

We found some wide spread test failures internally. I'm working on a
testcase. Politely revert the patch in the mean time. :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297124 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-07 07:40:10 +00:00
Nemanja Ivanovic
521df0adae [PowerPC] Fix failure with STBRX when store is narrower than the bswap
Fixes a crash caused by r296811 by truncating the input of the STBRX node
when the bswap is wider than i32.

Fixes https://bugs.llvm.org/show_bug.cgi?id=32140

Differential Revision: https://reviews.llvm.org/D30615


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297001 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-06 07:32:13 +00:00
Guozhi Wei
e225b39cd4 [PPC] Fix code generation for bswap(int32) followed by store16
This patch fixes pr32063.

Current code in PPCTargetLowering::PerformDAGCombine can transform

bswap
store

into a single PPCISD::STBRX instruction. but it doesn't consider the case that the operand size of bswap may be larger than store size. When it occurs, we need 2 modifications,

1 For the last operand of PPCISD::STBRX, we should not use DAG.getValueType(N->getOperand(1).getValueType()), instead we should use cast<StoreSDNode>(N)->getMemoryVT().

2 Before PPCISD::STBRX, we need to shift the original operand of bswap to the right side.

Differential Revision: https://reviews.llvm.org/D30362



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296811 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-02 21:07:59 +00:00
Nemanja Ivanovic
6981f9a951 [PowerPC][ELFv2ABI] Allocate parameter area on-demand to reduce stack frame size
This patch reduces the stack frame size by not allocating the parameter area if
it is not required. In the current implementation LowerFormalArguments_64SVR4
already handles the parameter area, but LowerCall_64SVR4 does not
(when calculating the stack frame size). What this patch does is make
LowerCall_64SVR4 consistent with LowerFormalArguments_64SVR4.

Committing on behalf of Hiroshi Inoue.

Differential Revision: https://reviews.llvm.org/D29881


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296771 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-02 17:38:59 +00:00
Tony Jiang
758e067345 [PowerPC] Expand ISEL instruction into if-then-else sequence.
Generally, the ISEL is expanded into if-then-else sequence, in some
cases (like when the destination register is the same with the true
or false value register), it may just be expanded into just the if
or else sequence.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292154 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 20:12:26 +00:00
Tony Jiang
748e859f36 Revert "[PowerPC] Expand ISEL instruction into if-then-else sequence."
This reverts commit 1d0e0374438ca6e153844c683826ba9b82486bb1.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292131 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 15:01:07 +00:00
Tony Jiang
541103a1c6 [PowerPC] Expand ISEL instruction into if-then-else sequence.
Generally, the ISEL is expanded into if-then-else sequence, in some
cases (like when the destination register is the same with the true
or false value register), it may just be expanded into just the if
or else sequence.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292128 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 14:43:12 +00:00
Eugene Zelenko
4a9353b234 [PowerPC] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291872 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 00:58:58 +00:00
Hal Finkel
68c84942ec [PowerPC] Fix logic dealing with nop after calls (and tail-call eligibility)
This change aims to unify and correct our logic for when we need to allow for
the possibility of the linker adding a TOC restoration instruction after a
call. This comes up in two contexts:

 1. When determining tail-call eligibility. If we make a tail call (i.e.
    directly branch to a function) then there is no place for the linker to add
    a TOC restoration.
 2. When determining when we need to add a nop instruction after a call.
    Likewise, if there is a possibility that the linker might need to add a
    TOC restoration after a call, then we need to put a nop after the call
    (the bl instruction).

First problem: We were using similar, but different, logic to decide (1) and
(2). This is just wrong. Both the resideInSameModule function (used when
determining tail-call eligibility) and the isLocalCall function (used when
deciding if the post-call nop is needed) were supposed to be determining the
same underlying fact (i.e. might a TOC restoration be needed after the call).
The same logic should be used in both places.

Second problem: The logic in both places was wrong. We only know that two
functions will share the same TOC when both functions come from the same
section of the same object. Otherwise the linker might cause the functions to
use different TOC base addresses (unless the multi-TOC linker option is
disabled, in which case only shared-library boundaries are relevant). There are
a number of factors that can cause functions to be placed in different sections
or come from different objects (-ffunction-sections, explicitly-specified
section names, COMDAT, weak linkage, etc.). All of these need to be checked.
The existing logic only checked properties of the callee, but the properties of
the caller must also be checked (for example, calling from a function in a
COMDAT section means calling between sections).

There was a conceptual error in the resideInSameModule function in that it
allowed tail calls to functions with weak linkage and protected/hidden
visibility. While protected/hidden visibility does prevent the function
implementation from being replaced at runtime (via interposition), it does not
prevent the linker from using an alternate implementation at link time (i.e.
using some strong definition to replace the provided weak one during linking).
If this happens, then we're still potentially looking at a required TOC
restoration upon return.

Otherwise, in general, the post-call nop is needed wherever ELF interposition
needs to be supported. We don't currently support ELF interposition at the IR
level (see http://lists.llvm.org/pipermail/llvm-dev/2016-November/107625.html
for more information), and I don't think we should try to make it appear to
work in the backend in spite of that fact. Unfortunately, because of the way
that the ABI works, we need to generate code as if we supported interposition
whenever the linker might insert stubs for the purpose of supporting it.

Differential Revision: https://reviews.llvm.org/D27231

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291003 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 21:05:13 +00:00
Chandler Carruth
e87e7067ed Revert r289638: [PowerPC] Fix logic dealing with nop after calls (and tail-call eligibility)
This patch appears to result in trampolines in vtables being miscompiled
when they in turn tail call a method.

I've posted some preliminary details about the failure on the thread for
this commit and talked to Hal. He was comfortable going ahead and
reverting until we sort out what is wrong.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289928 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-16 07:31:20 +00:00