The live range of an SSA value forms a sub-tree of the dominator tree.
That means the live ranges of two values overlap if and only if the def
of one value lies within the live range of the other.
This can be used to simplify the interference checking a bit: Visit each
def in the two registers about to be joined. Check for interference
against the value that is live in the other register at the def point
only. It is not necessary to scan the set of overlapping live ranges,
this interference check can be done while computing the value mapping
required for the final live range join.
The new algorithm is prepared to handle more complicated conflict
resolution - We can allow overlapping live ranges with different values
as long as the differing lanes are undef or unused in the other
register.
The implementation in this patch doesn't do that yet, it creates code
that is nearly identical to the old algorithm's, except:
- The new stripCopies() function sees through multiple copies while
the old RegistersDefinedFromSameValue() only can handle one.
- There are a few rare cases where the new algorithm can erase an
IMPLICIT_DEF instuction that RegistersDefinedFromSameValue() couldn't
handle.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163991 91177308-0d34-0410-b5e6-96231b3b80d8
Kill flags are removed more and more aggressively during the register
allocation passes, it is better to get information from LiveIntervals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163972 91177308-0d34-0410-b5e6-96231b3b80d8
- Find a legal vector type before casting and extracting element from it.
- As the new vector type may have more than 2 elements, build the final
hi/lo pair by BFS pairing them from bottom to top.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163830 91177308-0d34-0410-b5e6-96231b3b80d8
by xoring the high-bit. This fails if the source operand is a vector because we need to negate
each of the elements in the vector.
Fix rdar://12281066 PR13813.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163802 91177308-0d34-0410-b5e6-96231b3b80d8
are within the lifetime zone. Sometime legitimate usages of allocas are
hoisted outside of the lifetime zone. For example, GEPS may calculate the
address of a member of an allocated struct. This commit makes sure that
we only check (abort regions or assert) for instructions that read and write
memory using stack frames directly. Notice that by allowing legitimate
usages outside the lifetime zone we also stop checking for instructions
which use derivatives of allocas. We will catch less bugs in user code
and in the compiler itself.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163791 91177308-0d34-0410-b5e6-96231b3b80d8
Add some support for dealing with an object pointer on arguments.
Part of rdar://9797999
which now supports adding the object pointer attribute to the
subprogram as it should.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163754 91177308-0d34-0410-b5e6-96231b3b80d8
- BlockAddress has no support of BA + offset form and there is no way to
propagate that offset into machine operand;
- Add BA + offset support and a new interface 'getTargetBlockAddress' to
simplify target block address forming;
- All targets are modified to use new interface and X86 backend is enhanced to
support BA + offset addressing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163743 91177308-0d34-0410-b5e6-96231b3b80d8
SelectionDAG::getConstantFP(double Val, EVT VT, bool isTarget);
should not be used when Val is not a simple constant (as the comment in
SelectionDAG.h indicates). This patch avoids using this function
when folding an unknown constant through a bitcast, where it cannot be
guaranteed that Val will be a simple constant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163703 91177308-0d34-0410-b5e6-96231b3b80d8
The search for liveness is clipped to a specific number of instructions around the target MachineInstr, in order to avoid degenerating into an O(N^2) algorithm. It tries to use various clues about how instructions around (both before and after) a given MachineInstr use that register, to determine its state at the MachineInstr.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163695 91177308-0d34-0410-b5e6-96231b3b80d8
findLastUseBefore was previous considering virtreg liveness only, leading to
incorrect live intervals for reg units when instrs with physreg operands were
moved up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163685 91177308-0d34-0410-b5e6-96231b3b80d8
The input program may contain intructions which are not inside lifetime
markers. This can happen due to a bug in the compiler or due to a bug in
user code (for example, returning a reference to a local variable).
This commit adds checks that all of the instructions in the function and
invalidates lifetime ranges which do not contain all of the instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163678 91177308-0d34-0410-b5e6-96231b3b80d8
The Hexagon target decided to use a lot of functionality from the
target-independent scheduler. That's fine, and other targets should be
able to do the same. This reorg and API update makes that easy.
For the record, ScheduleDAGMI was not meant to be subclassed. Instead,
new scheduling algorithms should be able to implement
MachineSchedStrategy and be done. But if need be, it's nice to be
able to extend ScheduleDAGMI, so I also made that easier. The target
scheduler is somewhat more apt to break that way though.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163580 91177308-0d34-0410-b5e6-96231b3b80d8
This folding happens as early as possible for performance reasons, and to make sure it isn't foiled by other transforms (e.g. forming FMAs).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163519 91177308-0d34-0410-b5e6-96231b3b80d8
Previously we checked if the register is def'd in a block via the def/use list a
nd walked the list of kills to check if the register is killed in a block. Both
of these checks can be made much cheaper by walking the block first and
recording all defs and kills.
This reduces the compile time of the test case from PR13651 from 40s to 15s at
-O2. The compile time is still dominated by LV updating but now the main culprit
is SparseBitVector's slowness.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163478 91177308-0d34-0410-b5e6-96231b3b80d8
For some reason .lcomm uses byte alignment and .comm log2 alignment so we can't
use the same setting for both. Fix this by reintroducing the LCOMM enum.
I verified this against mingw's gcc.
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- Darwin lied about not supporting .lcomm and turned it into zerofill in the
asm parser. Push the zerofill-conversion down into macho-specific code.
- This makes the tri-state LCOMMType enum superfluous, there are no targets
without .lcomm.
- Do proper error reporting when trying to use .lcomm with alignment on a target
that doesn't support it.
- .comm and .lcomm alignment was parsed in bytes on COFF, should be power of 2.
- Fixes PR13755 (.lcomm crashes on ELF).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163395 91177308-0d34-0410-b5e6-96231b3b80d8
The RegisterCoalescer understands overlapping live ranges where one
register is defined as a copy of the other. With this change, register
allocators using LiveRegMatrix can do the same, at least for copies
between physical and virtual registers.
When a physreg is defined by a copy from a virtreg, allow those live
ranges to overlap:
%CL<def> = COPY %vreg11:sub_8bit; GR32_ABCD:%vreg11
%vreg13<def,tied1> = SAR32rCL %vreg13<tied0>, %CL<imp-use,kill>
We can assign %vreg11 to %ECX, overlapping the live range of %CL.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163336 91177308-0d34-0410-b5e6-96231b3b80d8
We will soon allow virtual register live ranges to overlap regunit live
ranges when the physreg is defined as a copy of the virtreg:
%EAX = COPY %vreg5
FOO %vreg5
BAR %EAX<kill>
There is no real interference since %vreg5 and %EAX have the same value
where they overlap.
This patch prevents addKillFlags from adding virtreg kill flags to FOO
where the assigned physreg is overlapping the virtual register live
range.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163335 91177308-0d34-0410-b5e6-96231b3b80d8
Kill flags are difficult to maintain, and liveness queries are better
handled by live intervals.
Kill flags are reinserted after register allocation by addKillFlags().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163334 91177308-0d34-0410-b5e6-96231b3b80d8
Implicit uses can be dynamically tied to defs. This will soon be used
for predicated instructions on ARM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163177 91177308-0d34-0410-b5e6-96231b3b80d8
The MachineOperand::TiedTo field was maintained, but not used.
This patch enables it in isRegTiedToDefOperand() and
isRegTiedToUseOperand() which are the actual functions use by the
register allocator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163153 91177308-0d34-0410-b5e6-96231b3b80d8
After much agonizing, use a full 4 bits of precious MachineOperand space
to encode this. This uses existing padding, and doesn't grow
MachineOperand beyond its current 32 bytes.
This allows tied defs among the first 15 operands on a normal
instruction, just like the current MCInstrDesc constraint encoding.
Inline assembly needs to be able to tie more than the first 15 operands,
and gets special treatment.
Tied uses can appear beyond 15 operands, as long as they are tied to a
def that's in range.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163151 91177308-0d34-0410-b5e6-96231b3b80d8
- CodeGenPrepare pass for identifying div/rem ops
- Backend specifies the type mapping using addBypassSlowDivType
- Enabled only for Intel Atom with O2 32-bit -> 8-bit
- Replace IDIV with instructions which test its value and use DIVB if the value
is positive and less than 256.
- In the case when the quotient and remainder of a divide are used a DIV
and a REM instruction will be present in the IR. In the non-Atom case
they are both lowered to IDIVs and CSE removes the redundant IDIV instruction,
using the quotient and remainder from the first IDIV. However,
due to this optimization CSE is not able to eliminate redundant
IDIV instructions because they are located in different basic blocks.
This is overcome by calculating both the quotient (DIV) and remainder (REM)
in each basic block that is inserted by the optimization and reusing the result
values when a subsequent DIV or REM instruction uses the same operands.
- Test cases check for the presents of the optimization when calculating
either the quotient, remainder, or both.
Patch by Tyler Nowicki!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163150 91177308-0d34-0410-b5e6-96231b3b80d8
No test case unfortunately as i couldn't find a target which fit all
the conditions needed to hit this code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163075 91177308-0d34-0410-b5e6-96231b3b80d8
Manage tied operands entirely internally to MachineInstr. This makes it
possible to change the representation of tied operands, as I will do
shortly.
The constraint that tied uses and defs must be in the same order was too
restrictive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163021 91177308-0d34-0410-b5e6-96231b3b80d8
I was too optimistic, inline asm can have tied operands that don't
follow the def order.
Fixes PR13742.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162998 91177308-0d34-0410-b5e6-96231b3b80d8
because it does not support CMOV of vectors. To implement this efficientlyi, we broadcast the condition bit and use a sequence of NAND-OR
to select between the two operands. This is the same sequence we use for targets that don't have vector BLENDs (like SSE2).
rdar://12201387
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When a MachineInstr is constructed, its implicit operands are added
first, then the explicit operands are inserted before the implicits.
MCInstrDesc has oprand flags like early clobber and operand ties that
apply to the explicit operands.
Don't look at those flags when the implicit operands are first added in
the explicit operands's positions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162910 91177308-0d34-0410-b5e6-96231b3b80d8
When there are multiple tied use-def pairs on an inline asm instruction,
the tied uses must appear in the same order as the defs.
It is possible to write an LLVM IR inline asm instruction that breaks
this constraint, but there is no reason for a front end to emit the
operands out of order.
The gnu inline asm syntax specifies tied operands as a single read/write
constraint "+r", so ouf of order operands are not possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162878 91177308-0d34-0410-b5e6-96231b3b80d8
For normal instructions, isTied() is set automatically by addOperand(),
based on MCInstrDesc, but inline asm has tied operands outside the
descriptor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162869 91177308-0d34-0410-b5e6-96231b3b80d8
Ordered memory operations are more constrained than volatile loads and
stores because they must be ordered with respect to all other memory
operations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162861 91177308-0d34-0410-b5e6-96231b3b80d8
It is technically allowed to move a normal load across a volatile load,
but probably not a good idea.
It is not allowed to move a load across an atomic load with
Ordering > Monotonic, and we model those with MOVolatile as well.
I recently removed the mayStore flag from atomic load instructions, so
they don't need a pseudo-opcode. This patch makes up for the difference.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162857 91177308-0d34-0410-b5e6-96231b3b80d8
The operands on an INLINEASM machine instruction are divided into groups
headed by immediate flag operands. Verify this structure.
Extract verifyTiedOperands(), and only call it for non-inlineasm
instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162849 91177308-0d34-0410-b5e6-96231b3b80d8
WHen running with -verify-machineinstrs, check that tied operands come
in matching use/def pairs, and that they are consistent with MCInstrDesc
when it applies.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162816 91177308-0d34-0410-b5e6-96231b3b80d8
The isTied bit is set automatically when a tied use is added and
MCInstrDesc indicates a tied operand. The tie is broken when one of the
tied operands is removed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162814 91177308-0d34-0410-b5e6-96231b3b80d8
While in SSA form, a MachineInstr can have pairs of tied defs and uses.
The tied operands are used to represent read-modify-write operands that
must be assigned the same physical register.
Previously, tied operand pairs were computed from fixed MCInstrDesc
fields, or by using black magic on inline assembly instructions.
The isTied flag makes it possible to add tied operands to any
instruction while getting rid of (some of) the inlineasm magic.
Tied operands on normal instructions are needed to represent predicated
individual instructions in SSA form. An extra <tied,imp-use> operand is
required to represent the output value when the instruction predicate is
false.
Adding a predicate to:
%vreg0<def> = ADD %vreg1, %vreg2
Will look like:
%vreg0<tied,def> = ADD %vreg1, %vreg2, pred:3, %vreg7<tied,imp-use>
The virtual register %vreg7 is the value given to %vreg0 when the
predicate is false. It will be assigned the same physreg as %vreg0.
This commit adds the isTied flag and sets it based on MCInstrDesc when
building an instruction. The flag is not used for anything yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162774 91177308-0d34-0410-b5e6-96231b3b80d8
Register operands are manipulated by a lot of target-independent code,
and it is not always possible to preserve target flags. That means it is
not safe to use target flags on register operands.
None of the targets in the tree are using register operand target flags.
External targets should be using immediate operands to annotate
instructions with operand modifiers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162770 91177308-0d34-0410-b5e6-96231b3b80d8
These extra flags are not required to properly order the atomic
load/store instructions. SelectionDAGBuilder chains atomics as if they
were volatile, and SelectionDAG::getAtomic() sets the isVolatile bit on
the memory operands of all atomic operations.
The volatile bit is enough to order atomic loads and stores during and
after SelectionDAG.
This means we set mayLoad on atomic_load, mayStore on atomic_store, and
mayLoad+mayStore on the remaining atomic read-modify-write operations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162733 91177308-0d34-0410-b5e6-96231b3b80d8
In SelectionDAGLegalize::ExpandLegalINT_TO_FP, expand INT_TO_FP nodes without
using any f64 operations if f64 is not a legal type.
Patch by Stefan Kristiansson.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162728 91177308-0d34-0410-b5e6-96231b3b80d8
It is legal to have a register node as an explicit operand, it shouldn't
be counted as an implicit use.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162591 91177308-0d34-0410-b5e6-96231b3b80d8
the case of multiple edges from one block to another.
A simple example is a switch statement with multiple values to the same
destination. The definition of an edge is modified from a pair of blocks to
a pair of PredBlock and an index into the successors.
Also set the weight correctly when building SelectionDAG from LLVM IR,
especially when converting a Switch.
IntegersSubsetMapping is updated to calculate the weight for each cluster.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162572 91177308-0d34-0410-b5e6-96231b3b80d8
output (we're emitting a specification already and the information
isn't changing) and we're not in old gdb compat mode.
Saves 1% on the debug information for a build of llvm.
Fixes rdar://11043421
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162493 91177308-0d34-0410-b5e6-96231b3b80d8
The logic for recomputing latency based on a ScheduleDAG edge was
shady. This bypasses the problem by requiring the client to provide
operand indices. This ensures consistent use of the machine model's
API.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162420 91177308-0d34-0410-b5e6-96231b3b80d8
Based on CR feedback from r162301 and Craig Topper's refactoring in r162347
here are a few other places that could use the same API (& in one instance drop
a Function.h dependency).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162367 91177308-0d34-0410-b5e6-96231b3b80d8
SelectionDAG's 'init' has not been called when the SelectionDAGBuilder is
constructed (in SelectionDAGISel's constructor), so this was previously always
initialized with 0.
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Even looking at the revision history I couldn't quite piece together why this
cast was ever written in the first place, but I assume it was because of some
change in the inheritance, perhaps this function was reimplemented in a
derived type & this caller was meant to get the base version (& it wasn't
virtual)?
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162301 91177308-0d34-0410-b5e6-96231b3b80d8
The getSumForBlock function was quadratic in the number of successors
because getSuccWeight would perform a linear search for an already known
iterator.
This patch was originally committed as r161460, but reverted again
because of assertion failures. Now that duplicate Machine CFG edges have
been eliminated, this works properly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162233 91177308-0d34-0410-b5e6-96231b3b80d8
IR that hasn't been through SimplifyCFG can look like this:
br i1 %b, label %r, label %r
Make sure we don't create duplicate Machine CFG edges in this case.
Fix the machine code verifier to accept conditional branches with a
single CFG edge.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162230 91177308-0d34-0410-b5e6-96231b3b80d8
The DAGCombiner tries to optimise a BUILD_VECTOR by checking if it
consists purely of get_vector_elts from one or two source vectors. If
so, it either makes a concat_vectors node or a shufflevector node.
However, it doesn't check the element type width of the underlying
vector, so if you have this sequence:
Node0: v4i16 = ...
Node1: i32 = extract_vector_elt Node0
Node2: i32 = extract_vector_elt Node0
Node3: v16i8 = BUILD_VECTOR Node1, Node2, ...
It will attempt to:
Node0: v4i16 = ...
NewNode1: v16i8 = concat_vectors Node0, ...
Where this is actually invalid because the element width is completely
different. This causes an assertion failure on DAG legalization stage.
Fix:
If output item type of BUILD_VECTOR differs from input item type.
Make concat_vectors based on input element type and then bitcast it to the output vector type. So the case described above will transformed to:
Node0: v4i16 = ...
NewNode1: v8i16 = concat_vectors Node0, ...
NewNode2: v16i8 = bitcast NewNode1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162195 91177308-0d34-0410-b5e6-96231b3b80d8
make it more consistent with its intended semantics.
The `linker_private_weak_def_auto' linkage type was meant to automatically hide
globals which never had their addresses taken. It has nothing to do with the
`linker_private' linkage type, which outputs the symbols with a `l' (ell) prefix
among other things.
The intended semantic is more like the `linkonce_odr' linkage type.
Change the name of the linkage type to `linkonce_odr_auto_hide'. And therefore
changing the semantics so that it produces the correct output for the linker.
Note: The old linkage name `linker_private_weak_def_auto' will still parse but
is not a synonym for `linkonce_odr_auto_hide'. This should be removed in 4.0.
<rdar://problem/11754934>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162114 91177308-0d34-0410-b5e6-96231b3b80d8
Increment the MBB iterator at the top of the loop to properly handle the
current (and previous) instructions getting erased.
This fixes PR13625.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162099 91177308-0d34-0410-b5e6-96231b3b80d8
Select instructions pick one of two virtual registers based on a
condition, like x86 cmov. On targets like ARM that support predication,
selects can sometimes be eliminated by predicating the instruction
defining one of the operands.
Teach PeepholeOptimizer to recognize select instructions, and ask the
target to optimize them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162059 91177308-0d34-0410-b5e6-96231b3b80d8
It never does anything when running 'make check', and it get's in the
way of updating live intervals in 2-addr.
The hook was originally added to help form IT blocks in Thumb2 code
before register allocation, but the pass ordering has changed since
then, and we run if-conversion after register allocation now.
When the MI scheduler is enabled, there will be no less than two
schedulers between 2-addr and Thumb2ITBlockPass, so this hook is
unlikely to help anything.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161794 91177308-0d34-0410-b5e6-96231b3b80d8
It is still possible to if-convert if the tail block has extra
predecessors, but the tail phis must be rewritten instead of being
removed.
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Detect when there is not enough available ILP, so if-conversion can't
speculate instructions for free.
Compute the lengthening of the critical path when inserting a select
instruction that depends on the condition as well as both sides of the
if.
Reject conversions that would stretch the critical path by more than
half a mispredict penalty.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161713 91177308-0d34-0410-b5e6-96231b3b80d8
Trace::getResourceLength() computes the number of cycles required to
execute the trace when ignoring data dependencies. The number can be
compared to the critical path to estimate the trace ILP.
Trace::getPHIDepth() computes the data dependency depth of a PHI in a
trace successor that isn't necessarily part of the trace.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161711 91177308-0d34-0410-b5e6-96231b3b80d8
When a trace ends with a back-edge, include PHIs in the loop header in
the height computations. This makes the critical path through a loop
more accurate by including the latencies of the last instructions in the
loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161688 91177308-0d34-0410-b5e6-96231b3b80d8
When replacing Old with New, it can happen that New is already a
successor. Add the old and new edge weights instead of creating a
duplicate edge.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161653 91177308-0d34-0410-b5e6-96231b3b80d8
This makes it possible to speed up def_iterator by stopping at the first
use. This makes def_empty() and getUniqueVRegDef() much faster when
there are many uses.
In a +Asserts build, LiveVariables is 100x faster in one case because
getVRegDef() has an assertion that would scan to the end of a
def_iterator chain.
Spill weight calculation is significantly faster (300x in one case)
because isTriviallyReMaterializable() calls MRI->isConstantPhysReg(%RIP)
which calls def_empty(%RIP).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161634 91177308-0d34-0410-b5e6-96231b3b80d8
Use a more conventional doubly linked list where the Prev pointers form
a cycle. This means it is no longer necessary to adjust the Prev
pointers when reallocating the VRegInfo array.
The test changes are required because the register allocation hint is
using the use-list order to break ties.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161633 91177308-0d34-0410-b5e6-96231b3b80d8
Register MachineOperands are kept in linked lists accessible via MRI's
reg_iterator interfaces. The linked list management was handled partly
by MachineOperand methods, partly by MRI methods.
Move all of the list management into MRI, delete
MO::AddRegOperandToRegInfo() and MO::RemoveRegOperandFromRegInfo().
Be more explicit about handling the cases where an MRI pointer isn't
available.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161632 91177308-0d34-0410-b5e6-96231b3b80d8
We filter out MachineLoop back-edges during the trace-building PO
traversals, but it is possible to have CFG cycles that aren't natural
loops, and MachineLoopInfo doesn't include such cycles.
Use a standard visited set to detect such CFG cycles, and completely
ignore them when picking traces.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161532 91177308-0d34-0410-b5e6-96231b3b80d8
We perform the following:
1> Use SUB instead of CMP for i8,i16,i32 and i64 in ISel lowering.
2> Modify MachineCSE to correctly handle implicit defs.
3> Convert SUB back to CMP if possible at peephole.
Removed pattern matching of (a>b) ? (a-b):0 and like, since they are handled
by peephole now.
rdar://11873276
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161462 91177308-0d34-0410-b5e6-96231b3b80d8
The getSumForBlock function was quadratic in the number of successors
because getSuccWeight would perform a linear search for an already known
iterator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161460 91177308-0d34-0410-b5e6-96231b3b80d8
This adds support for TargetIndex operands during isel. The meaning of
these (index, offset, flags) operands is entirely defined by the target.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161453 91177308-0d34-0410-b5e6-96231b3b80d8
A target index operand looks a lot like a constant pool reference, but
it is completely target-defined. It contains the 8-bit TargetFlags, a
32-bit index, and a 64-bit offset. It is preserved by all code generator
passes.
TargetIndex operands can be used to carry target-specific information in
cases where immediate operands won't suffice.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161441 91177308-0d34-0410-b5e6-96231b3b80d8
Compare the critical paths of the two traces through an if-conversion
candidate. If the difference is larger than the branch brediction
penalty, reject the if-conversion. If would never pay.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161433 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, MBP essentially aligned every branch target it could. This
bloats code quite a bit, especially non-looping code which has no real
reason to prefer aligned branch targets so heavily.
As Andy said in review, it's still a bit odd to do this without a real
cost model, but this at least has much more plausible heuristics.
Fixes PR13265.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161409 91177308-0d34-0410-b5e6-96231b3b80d8
If the result of a common subexpression is used at all uses of the candidate
expression, CSE should not increase the live range of the common subexpression.
rdar://11393714 and rdar://11819721
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161396 91177308-0d34-0410-b5e6-96231b3b80d8
This patch is mostly just refactoring a bunch of copy-and-pasted code, but
it also adds a check that the call instructions are readnone or readonly.
That check was already present for sin, cos, sqrt, log2, and exp2 calls, but
it was missing for the rest of the builtins being handled in this code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161282 91177308-0d34-0410-b5e6-96231b3b80d8
No functional change intended, except replacing a DenseMap with a
SmallDenseMap which should behave identically.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161281 91177308-0d34-0410-b5e6-96231b3b80d8
This is far from complete, and only changes behavior when the
-early-live-intervals flag is passed to llc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161273 91177308-0d34-0410-b5e6-96231b3b80d8
This option runs LiveIntervals before TwoAddressInstructionPass which
will eventually learn to exploit and update the analysis.
Eventually, LiveIntervals will run before PHIElimination, and we can get
rid of LiveVariables.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161270 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, the identity copy would survive through register allocation
before it was removed by the rewriter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161269 91177308-0d34-0410-b5e6-96231b3b80d8
The previous change caused fast isel to not attempt handling any calls to
builtin functions. That included things like "printf" and caused some
noticable regressions in compile time. I wanted to avoid having fast isel
keep a separate list of functions that had to be kept in sync with what the
code in SelectionDAGBuilder.cpp was handling. I've resolved that here by
moving the list into TargetLibraryInfo. This is somewhat redundant in
SelectionDAGBuilder but it will ensure that we keep things consistent.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161263 91177308-0d34-0410-b5e6-96231b3b80d8
