A noreturn nounwind function can be expected to never return in any way, and by
never returning it will also never have to restore any callee-saved registers
for its caller. This makes it possible to skip spills of those registers during
function entry, saving some stack space and time in the process. This is rather
useful for embedded targets with limited stack space.
Should fix PR9970.
Patch by myeisha (pmb).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329287 91177308-0d34-0410-b5e6-96231b3b80d8
The MachineOutliner has a bunch of target hooks that will call llvm_unreachable
if the target doesn't implement them. Therefore, if you enable the outliner on
such a target, it'll just crash. It'd be much better if it'd just *not* run
the outliner at all in this case.
This commit adds a hook to TargetInstrInfo that returns false by default.
Targets that implement the hook make it return true. The outliner checks the
return value of this hook to decide whether or not to continue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329220 91177308-0d34-0410-b5e6-96231b3b80d8
- MSVC was not OK with a static_assert referencing a non-static member
variable, even though it was just in a sizeof(expression). I move the
assert into the emit function, where it is probably more useful.
- Tests were failing in builds which did not have the X86 target
configured. Since this functionality is not target-specific, I have
removed the target specifiers from the .ll files.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329201 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch adds a DwarfAccelTableEmitter class, which generates an
accelerator table, as specified in DWARF v5 standard. At the moment it
only generates a DIE offset column and (if we are indexing more than one
compile unit) a CU column.
Indexing type units is not currently supported, as we don't even have
the ability to generate DWARF v5-compatible compile units.
The implementation is not data-source agnostic like the one generating
apple tables. This was not necessary as we currently only have one user
of this code, and without a second user it was not obvious to me how to
best abstract this. (The difference between these tables and the apple
ones is that they need a lot more metadata about the debug info they are
indexing).
The generation is triggered by the --accel-tables argument, which
supersedes the --dwarf-accel-tables arg -- the latter was a simple
on-off switch, but not we can choose between two kinds of accelerator
tables we can generate.
This is tested by parsing the generated tables with llvm-dwarfdump and
the DWARFVerifier, and I've also checked that GNU readelf is able to
make sense of the tables.
Differential Revision: https://reviews.llvm.org/D43286
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329179 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.
Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.
Reviewers: echristo, zturner, mzolotukhin, lhames
Reviewed By: echristo
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45135
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328940 91177308-0d34-0410-b5e6-96231b3b80d8
fptosi / fptoui round towards zero, and that's the same behavior as ISD::FTRUNC,
so replace a pair of casts with the equivalent node. We don't have to account for
special cases (NaN, INF) because out-of-range casts are undefined.
Differential Revision: https://reviews.llvm.org/D44909
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328921 91177308-0d34-0410-b5e6-96231b3b80d8
Currently EVT is in the IR layer only because of Function.cpp needing a very small piece of the functionality of EVT::getEVTString(). The rest of EVT is used in codegen making CodeGen a better place for it.
The previous code converted a Type* to EVT and then called getEVTString. This was only expected to handle the primitive types from Type*. Since there only a few primitive types, we can just print them as strings directly.
Differential Revision: https://reviews.llvm.org/D45017
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328806 91177308-0d34-0410-b5e6-96231b3b80d8
Implement TTI interface for targets to indicate that the LSR should give
priority to post-incrementing addressing modes.
Combination of patches by Sebastian Pop and Brendon Cahoon.
Differential Revision: https://reviews.llvm.org/D44758
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328490 91177308-0d34-0410-b5e6-96231b3b80d8
This is used by llvm tblgen as well as by LLVM Targets, so the only
common place is Support for now. (maybe we need another target for these
sorts of things - but for now I'm at least making them correct & we can
make them better if/when people have strong feelings)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328395 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds functions to allow MachineLICM to hoist invariant stores.
Currently, MachineLICM does not hoist any store instructions, however
when storing the same value to a constant spot on the stack, the store
instruction should be considered invariant and be hoisted. The function
isInvariantStore iterates each operand of the store instruction and checks
that each register operand satisfies isCallerPreservedPhysReg. The store
may be fed by a copy, which is hoisted by isCopyFeedingInvariantStore.
This patch also adds the PowerPC changes needed to consider the stack
register as caller preserved.
Differential Revision: https://reviews.llvm.org/D40196
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328326 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This pass sinks COPY instructions into a successor block, if the COPY is not
used in the current block and the COPY is live-in to a single successor
(i.e., doesn't require the COPY to be duplicated). This avoids executing the
the copy on paths where their results aren't needed. This also exposes
additional opportunites for dead copy elimination and shrink wrapping.
These copies were either not handled by or are inserted after the MachineSink
pass. As an example of the former case, the MachineSink pass cannot sink
COPY instructions with allocatable source registers; for AArch64 these type
of copy instructions are frequently used to move function parameters (PhyReg)
into virtual registers in the entry block..
For the machine IR below, this pass will sink %w19 in the entry into its
successor (%bb.1) because %w19 is only live-in in %bb.1.
```
%bb.0:
%wzr = SUBSWri %w1, 1
%w19 = COPY %w0
Bcc 11, %bb.2
%bb.1:
Live Ins: %w19
BL @fun
%w0 = ADDWrr %w0, %w19
RET %w0
%bb.2:
%w0 = COPY %wzr
RET %w0
```
As we sink %w19 (CSR in AArch64) into %bb.1, the shrink-wrapping pass will be
able to see %bb.0 as a candidate.
With this change I observed 12% more shrink-wrapping candidate and 13% more dead copies deleted in spec2000/2006/2017 on AArch64.
Reviewers: qcolombet, MatzeB, thegameg, mcrosier, gberry, hfinkel, john.brawn, twoh, RKSimon, sebpop, kparzysz
Reviewed By: sebpop
Subscribers: evandro, sebpop, sfertile, aemerson, mgorny, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D41463
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328237 91177308-0d34-0410-b5e6-96231b3b80d8
As in SystemZ backend, correctly propagate node ids when inserting new
unselected nodes into the DAG during instruction Seleciton for X86
target.
Fixes PR36865.
Reviewers: jyknight, craig.topper
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D44797
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328233 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds functions to allow MachineLICM to hoist invariant stores.
Currently, MachineLICM does not hoist any store instructions, however
when storing the same value to a constant spot on the stack, the store
instruction should be considered invariant and be hoisted. The function
isInvariantStore iterates each operand of the store instruction and checks
that each register operand satisfies isCallerPreservedPhysReg. The store
may be fed by a copy, which is hoisted by isCopyFeedingInvariantStore.
This patch also adds the PowerPC changes needed to consider the stack
register as caller preserved.
Differential Revision: https://reviews.llvm.org/D40196
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327856 91177308-0d34-0410-b5e6-96231b3b80d8
This matches what we do in SDNode.
This should allow SDValue::dump to be used in the debugger without getting an error if you don't pass an argument.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327811 91177308-0d34-0410-b5e6-96231b3b80d8
X86 Supports Indirect Branch Tracking (IBT) as part of Control-Flow Enforcement Technology (CET).
IBT instruments ENDBR instructions used to specify valid targets of indirect call / jmp.
The `nocf_check` attribute has two roles in the context of X86 IBT technology:
1. Appertains to a function - do not add ENDBR instruction at the beginning of the function.
2. Appertains to a function pointer - do not track the target function of this pointer by adding nocf_check prefix to the indirect-call instruction.
This patch implements `nocf_check` context for Indirect Branch Tracking.
It also auto generates `nocf_check` prefixes before indirect branchs to jump tables that are guarded by range checks.
Differential Revision: https://reviews.llvm.org/D41879
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327767 91177308-0d34-0410-b5e6-96231b3b80d8
This patch considers the experimental vector reduce intrinsics in the default
implementation of getIntrinsicInstrCost. The cost of these intrinsics is
computed with getArithmeticReductionCost and getMinMaxReductionCost. This patch
also adds a test case for AArch64 that indicates the costs we currently compute
for vector reduce intrinsics. These costs are inaccurate and will be updated in
a follow-on patch.
Differential Revision: https://reviews.llvm.org/D44489
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327698 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Local values are constants, global addresses, and stack addresses that
can't be folded into the instruction that uses them. For example, when
storing the address of a global variable into memory, we need to
materialize that address into a register.
FastISel doesn't want to materialize any given local value more than
once, so it generates all local value materialization code at
EmitStartPt, which always dominates the current insertion point. This
allows it to maintain a map of local value registers, and it knows that
the local value area will always dominate the current insertion point.
The downside is that local value instructions are always emitted without
a source location. This is done to prevent jumpy line tables, but it
means that the local value area will be considered part of the previous
statement. Consider this C code:
call1(); // line 1
++global; // line 2
++global; // line 3
call2(&global, &local); // line 4
Today we end up with assembly and line tables like this:
.loc 1 1
callq call1
leaq global(%rip), %rdi
leaq local(%rsp), %rsi
.loc 1 2
addq $1, global(%rip)
.loc 1 3
addq $1, global(%rip)
.loc 1 4
callq call2
The LEA instructions in the local value area have no source location and
are treated as being on line 1. Stepping through the code in a debugger
and correlating it with the assembly won't make much sense, because
these materializations are only required for line 4.
This is actually problematic for the VS debugger "set next statement"
feature, which effectively assumes that there are no registers live
across statement boundaries. By sinking the local value code into the
statement and fixing up the source location, we can make that feature
work. This was filed as https://bugs.llvm.org/show_bug.cgi?id=35975 and
https://crbug.com/793819.
This change is obviously not enough to make this feature work reliably
in all cases, but I felt that it was worth doing anyway because it
usually generates smaller, more comprehensible -O0 code. I measured a
0.12% regression in code generation time with LLC on the sqlite3
amalgamation, so I think this is worth doing.
There are some special cases worth calling out in the commit message:
1. local values materialized for phis
2. local values used by no-op casts
3. dead local value code
Local values can be materialized for phis, and this does not show up as
a vreg use in MachineRegisterInfo. In this case, if there are no other
uses, this patch sinks the value to the first terminator, EH label, or
the end of the BB if nothing else exists.
Local values may also be used by no-op casts, which adds the register to
the RegFixups table. Without reversing the RegFixups map direction, we
don't have enough information to sink these instructions.
Lastly, if the local value register has no other uses, we can delete it.
This comes up when fastisel tries two instruction selection approaches
and the first materializes the value but fails and the second succeeds
without using the local value.
Reviewers: aprantl, dblaikie, qcolombet, MatzeB, vsk, echristo
Subscribers: dotdash, chandlerc, hans, sdardis, amccarth, javed.absar, zturner, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D43093
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327581 91177308-0d34-0410-b5e6-96231b3b80d8
Relanding after fixing NodeId Invariant.
Cleanup cycle/validity checks in ISel (IsLegalToFold,
HandleMergeInputChains) and X86 (isFusableLoadOpStore). Now do a full
search for cycles / dependencies pruning the search when topological
property of NodeId allows.
As part of this propogate the NodeId-based cutoffs to narrow
hasPreprocessorHelper searches.
Reviewers: craig.topper, bogner
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D41293
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327171 91177308-0d34-0410-b5e6-96231b3b80d8
Instruction Selection makes use of the topological ordering of nodes
by node id (a node's operands have smaller node id than it) when doing
cycle detection. During selection we may violate this property as a
selection of multiple nodes may induce a use dependence (and thus a
node id restriction) between two unrelated nodes. If a selected node
has an unselected successor this may allow us to miss a cycle in
detection an invalid selection.
This patch fixes this by marking all unselected successors of a
selected node have negated node id. We avoid pruning on such negative
ids but still can reconstruct the original id for pruning.
In-tree targets have been updated to replace DAG-level replacements
with ISel-level ones which enforce this property.
This preemptively fixes PR36312 before triggering commit r324359 relands
Reviewers: craig.topper, bogner, jyknight
Subscribers: arsenm, nhaehnle, javed.absar, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D43198
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327170 91177308-0d34-0410-b5e6-96231b3b80d8
All uses conservatively assume in early exit case that it will be a
predecessor. Changing default removes checking code in all uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327169 91177308-0d34-0410-b5e6-96231b3b80d8
The retpoline mitigation for variant 2 of CVE-2017-5715 inhibits the
branch predictor, and as a result it can lead to a measurable loss of
performance. We can reduce the performance impact of retpolined virtual
calls by replacing them with a special construct known as a branch
funnel, which is an instruction sequence that implements virtual calls
to a set of known targets using a binary tree of direct branches. This
allows the processor to speculately execute valid implementations of the
virtual function without allowing for speculative execution of of calls
to arbitrary addresses.
This patch extends the whole-program devirtualization pass to replace
certain virtual calls with calls to branch funnels, which are
represented using a new llvm.icall.jumptable intrinsic. It also extends
the LowerTypeTests pass to recognize the new intrinsic, generate code
for the branch funnels (x86_64 only for now) and lay out virtual tables
as required for each branch funnel.
The implementation supports full LTO as well as ThinLTO, and extends the
ThinLTO summary format used for whole-program devirtualization to
support branch funnels.
For more details see RFC:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120672.html
Differential Revision: https://reviews.llvm.org/D42453
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327163 91177308-0d34-0410-b5e6-96231b3b80d8
Added helpers to build G_FCONSTANT, along with matching ConstantFP and
unit tests for the same.
Sample usage.
auto MIB = Builder.buildFConstant(s32, 0.5); // Build IEEESingle
For Matching the above
const ConstantFP* Tmp;
mi_match(DstReg, MRI, m_GFCst(Tmp));
https://reviews.llvm.org/D44128
reviewed by: volkan
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327152 91177308-0d34-0410-b5e6-96231b3b80d8
The code to match and produce more x86 vector blends was enabled for all
architectures even though the transform may pessimize the code for other
architectures that do not provide a vector blend instruction.
Added an aarch64 testcase to check that a VZIP instruction is generated instead
of byte movs.
Differential Revision: https://reviews.llvm.org/D44118
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327132 91177308-0d34-0410-b5e6-96231b3b80d8
The code checks Level == AfterLegalizeDAG which is the fourth and last of the possible DAG combine stages that we have.
There is a Level called AfterLegalVectorOps, but that's the third DAG combine and it doesn't always run.
A function called isAfterLegalVectorOps should imply it returns true in either of the DAG combines that runs after the legalize vector ops stage, but that's not what this function does.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326832 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Fabs is a common floating-point operation, especially for some expansions. This patch adds
a new generic opcode for llvm.fabs.* intrinsic in order to avoid building/matching this intrinsic.
Reviewers: qcolombet, aditya_nandakumar, dsanders, rovka
Reviewed By: aditya_nandakumar
Subscribers: kristof.beyls, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D43864
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326749 91177308-0d34-0410-b5e6-96231b3b80d8
