Each use of a value should be jointly dominated by the union of defs and
undefs. It can happen that it will only be jointly dominated by undefs,
and that is still legal. Make sure that the verifier is aware of that.
llvm-svn: 339924
Subregister liveness applies selectively to register classes with certain
properties. Make sure that when it's enabled, it applies to a given virtual
register (in virtual register rewriter).
llvm-svn: 339784
Some instructions expand to more than one decoder group.
This has been hitherto ignored, but is handled with this patch.
Review: Ulrich Weigand
https://reviews.llvm.org/D50187
llvm-svn: 338849
The DAG combiner logic to simplify AND masks in shift counts is invalid.
While it is true that the SystemZ shift instructions ignore all but the
low 6 bits of the shift count, it is still invalid to simplify the AND
masks while the DAG still uses the standard shift operators (which are
*not* defined to match the SystemZ instruction behavior).
Instead, this patch performs equivalent operations during instruction
selection. For completely removing the AND, this now happens via
additional DAG match patterns implemented by a multi-alternative
PatFrags. For simplifying a 32-bit AND to a 16-bit AND, the existing DAG
patterns were already mostly OK, they just needed an output XForm to
actually truncate the immediate value.
Unfortunately, the latter change also exposed a bug in TableGen: it
seems XForms are currently only handled correctly for direct operands of
the outermost operation node. This patch also fixes that bug by simply
recurring through the whole pattern. This should be NFC for all other
targets.
Differential Revision: https://reviews.llvm.org/D50096
llvm-svn: 338521
Since z13, the max group size will be 2 if any μop has more than 3 register
sources.
This has been ignored sofar in the SystemZHazardRecognizer, but is now
handled by recognizing those instructions and adjusting the tracking of
decoding and the cost heuristic for grouping.
Review: Ulrich Weigand
https://reviews.llvm.org/D49847
llvm-svn: 338368
As a consequence of recent discussions
(http://lists.llvm.org/pipermail/llvm-dev/2018-May/123164.html), this patch
changes the SystemZ SchedModels so that the IssueWidth is 6, which is the
decoder capacity, and NumMicroOps become the number of decoder slots needed
per instruction.
In addition, the SchedWrite latencies now match the MachineInstructions
def-operand indexes, and ReadAdvances have been added on instructions with
one register operand and one memory operand.
Review: Ulrich Weigand
https://reviews.llvm.org/D47008
llvm-svn: 337538
See https://reviews.llvm.org/D47106 for details.
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D47171
This commit drops that patch's changes to:
llvm/test/CodeGen/NVPTX/f16x2-instructions.ll
llvm/test/CodeGen/NVPTX/param-load-store.ll
For some reason, the dos line endings there prevent me from commiting
via the monorepo. A follow-up commit (not via the monorepo) will
finish the patch.
llvm-svn: 336843
With compilation fix.
Original commit message:
D39788 added a '.stack-size' section containing metadata on function stack sizes
to output ELF files behind the new -stack-size-section flag.
This change does following two things on top:
1) Imagine the case when there are -ffunction-sections flag given and there are text sections in COMDATs.
The patch adds a '.stack-size' section into corresponding COMDAT group, so that linker will be able to
eliminate them fast during resolving the COMDATs.
2) Patch sets a SHF_LINK_ORDER flag and links '.stack-size' with the corresponding .text.
With that linker will be able to do -gc-sections on dead stack sizes sections.
Differential revision: https://reviews.llvm.org/D46874
llvm-svn: 335336
D39788 added a '.stack-size' section containing metadata on function stack sizes
to output ELF files behind the new -stack-size-section flag.
This change does following two things on top:
1) Imagine the case when there are -ffunction-sections flag given and there are text sections in COMDATs.
The patch adds a '.stack-size' section into corresponding COMDAT group, so that linker will be able to
eliminate them fast during resolving the COMDATs.
2) Patch sets a SHF_LINK_ORDER flag and links '.stack-size' with the corresponding .text.
With that linker will be able to do -gc-sections on dead stack sizes sections.
Differential revision: https://reviews.llvm.org/D46874
llvm-svn: 335332
Summary:
When the branch folder hoist code into a predecessor it adjust live-in's
in the blocks it hoist code from. However it fail to handle hoisted code
that contain a defed register that originally is live-in in the block
through a super register.
This is fixed by replacing the live-in handling code with calls to
utility functions in LivePhysRegs.
Reviewers: kparzysz, gberry, MatzeB, uweigand, aprantl
Reviewed By: kparzysz
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47529
llvm-svn: 334163
Previously, this pass would look at the (static) set returned by
getCallPreservedMask() and add those back as preserved in the case when
isSafeForNoCSROpt() returns false.
A problem is that a target may have to save some registers even when NoCSROpt
takes place. For instance, on SystemZ, the return register is needed upon
return from a function.
Furthermore, getCallPreservedMask() only includes the registers that the
target actually wishes to emit save/restore instructions for. This means that
subregs and (fully saved) superregs are missing.
This patch instead takes the (dynamic) set returned by target for the
function from determineCalleeSaves() and then adds sub/super regs to build
the set to be used when building the RegMask for the function.
Review: Quentin Colombet, Ulrich Weigand
https://reviews.llvm.org/D46315
llvm-svn: 333261
Don't assume the alias of a defined reg is always already in the set.
As the test case in https://bugs.llvm.org/show_bug.cgi?id=36587 discovered,
it is wrong to assume that all the aliases of the defined register in the
*current function* is already present in the UsedPhysRegsMask.
This patch changes this so that any definition in the current function of a
phys-reg always results in all its aliases inserted into the set of defined
registers.
Review: Quentin Colombet
https://reviews.llvm.org/D45157
llvm-svn: 331509
This provides an optimized implementation of SADDO/SSUBO/UADDO/USUBO
as well as ADDCARRY/SUBCARRY on top of the new CC implementation.
In particular, multi-word arithmetic now uses UADDO/ADDCARRY instead
of the old ADDC/ADDE logic, which means we no longer need to use
"glue" links for those instructions. This also allows making full
use of the memory-based instructions like ALSI, which couldn't be
recognized due to limitations in the DAG matcher previously.
Also, the llvm.sadd.with.overflow et.al. intrinsincs now expand to
directly using the ADD instructions and checking for a CC 3 result.
llvm-svn: 331203
Currently, an instruction setting the condition code is linked to
the instruction using the condition code via a "glue" link in the
SelectionDAG. This has a number of drawbacks; in particular, it
means the same CC cannot be used by multiple users. It also makes
it more difficult to efficiently implement SADDO et. al.
This patch changes the back-end to represent CC dependencies as
normal values during SelectionDAG matching, along the lines of
how this is handled in the X86 back-end already.
In addition to the core mechanics of updating all relevant patterns,
this requires a number of additional changes:
- We now need to be able to spill/restore a CC value into a GPR
if necessary. This means providing a copyPhysReg implementation
for moves involving CC, and defining getCrossCopyRegClass.
- Since we still prefer to avoid such spills, we provide an override
for IsProfitableToFold to avoid creating a merged LOAD / ICMP if
this would result in multiple users of the CC.
- combineCCMask no longer requires a single CC user, and no longer
need to be careful about preventing invalid glue/chain cycles.
- emitSelect needs to be more careful in marking CC live-in to
the basic block it generates. Also, we can now optimize the
case of multiple subsequent selects with the same condition
just like X86 does.
llvm-svn: 331202
If we have LOCR instructions, select them directly from SelectionDAG
instead of first going through a pseudo instruction and then using
the custom inserter to emit the LOCR.
Provide Select pseudo-instructions for VR32/VR64 if we have vector
instructions, to avoid having to go through the first 16 FPRs
unnecessarily.
If we do not have LOCFHR, prefer using LOCR followed by a move
over a conditional branch.
llvm-svn: 331191
This patch fixes an issue exposed on the SystemZ build bots when committing
https://reviews.llvm.org/rL327856. The hoisting was temporarily disabled with
an option. This patch now re-enables hoisting and checks that we only hoist a
store instruction when all its operands are either constant caller preserved
registers or immediates.
Differential Revision: https://reviews.llvm.org/D45286
llvm-svn: 329577
If DoneMBB becomes empty it must have CC added to its live-in list, since it
will fall-through into EndMBB. This happens when the CLC loop does the
complete range.
Review: Ulrich Weigand
llvm-svn: 327834
Improve/implement these methods to improve DAG combining. This mainly
concerns intrinsics.
Some constant operands to SystemZISD nodes have been marked Opaque to avoid
transforming back and forth between generic and target nodes infinitely.
Review: Ulrich Weigand
llvm-svn: 327765
The BITCAST handling in computeKnownBits() previously only worked for little
endian.
This patch reverses the iteration over elements for a big endian target which
allows this to work in this case also.
SystemZ test case.
Review: Eli Friedman
https://reviews.llvm.org/D44249
llvm-svn: 327764
splitMergedValStore will split a store into two if target prefers this, or if
-force-split-store is passed.
This patch adds the missing handling for endianness in this function along
with a test case.
Review: Eli Friedman
https://reviews.llvm.org/D44396
llvm-svn: 327375
This adds back-end support for the anyregcc calling convention
for use with patchpoints.
Since all registers are considered call-saved with anyregcc
(except for 0 and 1 which may still be clobbered by PLT stubs
and the like), this required adding support for saving and
restoring vector registers in prologue/epilogue code for the
first time. This is not used by any other calling convention.
llvm-svn: 326612
On SystemZ we need to provide a register save area of 160 bytes to
any called function. This size needs to be added when allocating
stack in the function prologue. However, it was not accounted for
as part of MachineFrameInfo::getStackSize(); instead the back-end
used a private routine getAllocatedStackSize().
This is OK for code-gen purposes, but it breaks other users of
the getStackSize() routine, in particular it breaks the recently-
added -stack-size-section feature.
Fix this by updating the main stack size tracked by common code
(in emitPrologue) instead of using the private routine.
No change in code generation intended.
llvm-svn: 326610
This adds support for specifying vector registers for use with inline
asm statements, either via the 'v' constraint or by explicit register
names (v0 ... v31).
llvm-svn: 326609
Masking first, prevents the extend from being combine with loads. Its also interfering with some vXi1 extraction code.
Differential Revision: https://reviews.llvm.org/D42679
llvm-svn: 326500
Re-enable commit r323991 now that r325931 has been committed to make
MachineOperand::isRenamable() check more conservative w.r.t. code
changes and opt-in on a per-target basis.
llvm-svn: 326208
This reverts commit r323991.
This commit breaks target that don't model all the register constraints
in TableGen. So far the workaround was to set the
hasExtraXXXRegAllocReq, but it proves that it doesn't cover all the
cases.
For instance, when mutating an instruction (like in the lowering of
COPYs) the isRenamable flag is not properly updated. The same problem
will happen when attaching machine operand from one instruction to
another.
Geoff Berry is working on a fix in https://reviews.llvm.org/D43042.
llvm-svn: 325421
When handling vectors with non byte-sized elements, reverse the order of the
elements in the built integer if the target is Big-Endian.
SystemZ tests updated.
Review: Eli Friedman, Ulrich Weigand.
https://reviews.llvm.org/D42786
llvm-svn: 324063
test/CodeGen/SystemZ/vec-trunc-to-i1.ll was marked as a temporary
FAIL when it was previously updated when it needed one more COPY.
This was however wrong, since the loop body had been reduced
significantly, and it was actually an improvement.
Review: Ulrich Weigand.
llvm-svn: 324060
Summary:
This change extends MachineCopyPropagation to do COPY source forwarding
and adds an additional run of the pass to the default pass pipeline just
after register allocation.
This version of this patch uses the newly added
MachineOperand::isRenamable bit to avoid forwarding registers is such a
way as to violate constraints that aren't captured in the
Machine IR (e.g. ABI or ISA constraints).
This change is a continuation of the work started in D30751.
Reviewers: qcolombet, javed.absar, MatzeB, jonpa, tstellar
Subscribers: tpr, mgorny, mcrosier, nhaehnle, nemanjai, jyknight, hfinkel, arsenm, inouehrs, eraman, sdardis, guyblank, fedor.sergeev, aheejin, dschuff, jfb, myatsina, llvm-commits
Differential Revision: https://reviews.llvm.org/D41835
llvm-svn: 323991
Summary:
In Instruction Selection UpdateChains replaces all matched Nodes'
chain references including interior token factors and deletes them.
This may allow nodes which depend on these interior nodes but are not
part of the set of matched nodes to be left with a dangling dependence.
Avoid this by doing the replacement for matched non-TokenFactor nodes.
Fixes PR36164.
Reviewers: jonpa, RKSimon, bogner
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D42754
llvm-svn: 323977
Discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html
In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.
llvm-svn: 323922
Since these methods will assert if the integer does not fit into 64 bits,
it is necessary to do this check before calling them in
supportedAddressingMode().
Review: Ulrich Weigand.
llvm-svn: 323866
This was completely broken, but hopefully fixed by this patch.
In cases where it is needed, a vector with non byte-sized elements is stored
by extracting, zero-extending, shift:ing and or:ing the elements into an
integer of the same width as the vector, which is then stored.
Review: Eli Friedman, Ulrich Weigand
https://reviews.llvm.org/D42100#inline-369520https://bugs.llvm.org/show_bug.cgi?id=35520
llvm-svn: 323042
On current machines we have load-on-condition instructions that can be
used to directly implement the SETCC semantics. If we have those, it is
always preferable to use them instead of generating the IPM sequence.
llvm-svn: 322989
In order to implement a test whether a compare-and-swap succeeded, the
SystemZ back-end currently emits a rather inefficient sequence of first
converting the CC result into an integer, and then testing that integer
against zero. This commit changes the back-end to simply directly test
the CC value set by the compare-and-swap instruction.
llvm-svn: 322988
The SystemZ back-end uses a sequence of IPM followed by arithmetic
operations to implement the SETCC primitive. This is currently done
early during SelectionDAG. This patch moves generating those sequences
to much later in SelectionDAG (during PreprocessISelDAG).
This doesn't change much in generated code by itself, but it allows
further enhancements that will be checked-in as follow-on commits.
llvm-svn: 322987
BRCTH is capable of a long branch which needs to be recognized during branch
relaxation. This is done by checking for ExtraRelaxSize == 0.
Review: Ulrich Weigand
llvm-svn: 322688
Since a load and test instruction treat its operands as signed, it can only
replace a logical compare for EQ/NE uses.
Review: Ulrich Weigand
https://bugs.llvm.org/show_bug.cgi?id=35662
llvm-svn: 322488
Prefetches used to always be chained between any previous and following
memory accesses. The problem with this was that later optimizations, such as
folding of a load into the user instruction, got disrupted.
This patch relaxes the chaining of prefetches in order to remedy this.
Reveiw: Hal Finkel
https://reviews.llvm.org/D38886
llvm-svn: 322163
Since a load and test instruction treat its operands as signed, it can only
replace a logical compare for EQ/NE uses.
Review: Ulrich Weigand
https://bugs.llvm.org/show_bug.cgi?id=35662
llvm-svn: 322161
Planning to add support for named vregs. This puts is in a conundrum since
physregs are named as well. To rectify this we need to use a sigil other than
'%' for physregs in MIR. We've settled on using '$' for physregs but first we
must repurpose it from external symbols using it, which is what this commit is
all about. We think '&' will have familiar semantics for C/C++ users.
llvm-svn: 322146
Summary:
Add isRenamable() predicate to MachineOperand. This predicate can be
used by machine passes after register allocation to determine whether it
is safe to rename a given register operand. Register operands that
aren't marked as renamable may be required to be assigned their current
register to satisfy constraints that are not captured by the machine
IR (e.g. ABI or ISA constraints).
Reviewers: qcolombet, MatzeB, hfinkel
Subscribers: nemanjai, mcrosier, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D39400
llvm-svn: 320503
Csmith discovered a program that caused wrong code generation with -O0:
When handling a SIGN_EXTEND in expandRxSBG(), RxSBG.BitSize may be less than
the Input width (if a truncate was previously traversed), so maskMatters()
should be called with a masked based on the width of the sign extend result
instead.
Review: Ulrich Weigand
llvm-svn: 319892
When folding a shift into a test-under-mask comparison, make sure that
there is no loss of precision when creating the shifted comparison
value. This usually never happens, except for certain always-true
comparisons in unoptimized code.
Fixes PR35529.
llvm-svn: 319818
This has proven a healthy exercise, as many cases of incorrect instruction
flags were corrected in the process. As part of this, IntrWriteMem was added
to several SystemZ instrinsics.
Furthermore, a bug was exposed in TwoAddress with this change (as incorrect
hasSideEffects flags were removed and instructions could now be sunk), and
the test case for that bugfix (r319646) is included here as
test/CodeGen/SystemZ/twoaddr-sink.ll.
One temporary test regression (one extra copy) which will hopefully go away
in upcoming patches for similar cases:
test/CodeGen/SystemZ/vec-trunc-to-i1.ll
Review: Ulrich Weigand.
https://reviews.llvm.org/D40437
llvm-svn: 319756
MachineRegisterInfo used to allow just one regalloc hint per virtual
register. This patch extends this to a vector of regalloc hints, which is
filled in by common code with sorted copy hints. Such hints will make for
more ID copies that can be removed.
NB! This improvement is currently (and hopefully temporarily) *disabled* by
default, except for SystemZ. The only reason for this is the big impact this
has on tests, which has unfortunately proven unmanageable. It was a long
while since all the tests were updated and just waiting for review (which
didn't happen), but now targets have to enable this themselves
instead. Several targets could get a head-start by downloading the tests
updates from the Phabricator review. Thanks to those who helped, and sorry
you now have to do this step yourselves.
This should be an improvement generally for any target!
The target may still create its own hint, in which case this has highest
priority and is stored first in the vector. If it has target-type, it will
not be recomputed, as per the previous behaviour.
The temporary hook enableMultipleCopyHints() will be removed as soon as all
targets return true.
Review: Quentin Colombet, Ulrich Weigand.
https://reviews.llvm.org/D38128
llvm-svn: 319754
As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.
The MIR printer prints the IR name of a MBB only for block definitions.
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix
Differential Revision: https://reviews.llvm.org/D40422
llvm-svn: 319665
output
As part of the unification of the debug format and the MIR format,
always use `printReg` to print all kinds of registers.
Updated the tests using '_' instead of '%noreg' until we decide which
one we want to be the default one.
Differential Revision: https://reviews.llvm.org/D40421
llvm-svn: 319445
Csmith generated a program where a store after load to the same address did
not get chained after the new load created during DAG legalizing, and so
performed an illegal overwrite of the expected value.
When the new zero-extending load is created, the chain users of the original
load must be updated, which was not done previously.
A similar case was also found and handled in lowerBITCAST.
Review: Ulrich Weigand
https://reviews.llvm.org/D40542
llvm-svn: 319409
As part of the unification of the debug format and the MIR format,
always print registers as lowercase.
* Only debug printing is affected. It now follows MIR.
Differential Revision: https://reviews.llvm.org/D40417
llvm-svn: 319187
Summary:
Now that store-merge is only generates type-safe stores, do a second
pass just before instruction selection to allow lowered intrinsics to
be merged as well.
Reviewers: jyknight, hfinkel, RKSimon, efriedma, rnk, jmolloy
Subscribers: javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33675
llvm-svn: 319036
Since i1 is a legal type, this:
NumBytes = Op1->getMemoryVT().getSizeInBits() >> 3;
is wrong and should be instead
NumBytes = Op0->getMemoryVT().getStoreSize();
There seems to be more places where this should be fixed outside DAGCombiner.
Review: Hal Finkel
https://bugs.llvm.org/show_bug.cgi?id=35366
llvm-svn: 318824
This patch peels off the top case in switch statement into a branch if the
probability exceeds a threshold. This will help the branch prediction and
avoids the extra compares when lowering into chain of branches.
Differential Revision: http://reviews.llvm.org/D39262
llvm-svn: 318202
In rare cases, common code will attempt to select an OR of two
constants. This confuses the logic in splitLargeImmediate,
causing an internal error during isel. Fixed by simply leaving
this case to common code to handle.
This fixes PR34859.
llvm-svn: 318187
Before using the 32-bit RISBMux set of instructions we need to
verify that the input bits are actually within range of the 32-bit
instruction. This fixer PR35289.
llvm-svn: 318177
* The method getRegAllocationHints() is now of bool type instead of void. If
true is returned, regalloc (AllocationOrder) will *only* try to allocate the
hints, as opposed to merely trying them before non-hinted registers.
* TargetRegisterInfo::getRegAllocationHints() is implemented for SystemZ with
an increase in number of LOCRs.
In this case, it is desired to force the hints even though there is a slight
increase in spilling, because if a non-hinted register would be allocated,
the LOCRMux pseudo would have to be expanded with a jump sequence. The LOCR
(Load On Condition) SystemZ instruction must have both operands in either the
low or high part of the 64 bit register.
Reviewers: Quentin Colombet and Ulrich Weigand
https://reviews.llvm.org/D36795
llvm-svn: 317879
We don't really need any special handling of "offsettable"
memory addresses, but since some existing code uses inline
asm statements with the "o" constraint, add support for this
constraint for compatibility purposes.
llvm-svn: 317807
The machine scheduler (before register allocation) is enabled by default for
SystemZ.
The SelectionDAG scheduling preference now becomes source order scheduling
(was regpressure).
Review: Ulrich Weigand
https://reviews.llvm.org/D37977
llvm-svn: 315063
Implement shouldCoalesce() to help regalloc avoid running out of GR128
registers.
If a COPY involving a subreg of a GR128 is coalesced, the live range of the
GR128 virtual register will be extended. If this happens where there are
enough phys-reg clobbers present, regalloc will run out of registers (if
there is not a single GR128 allocatable register available).
This patch tries to allow coalescing only when it can prove that this will be
safe by checking the (local) interval in question.
Review: Ulrich Weigand, Quentin Colombet
https://reviews.llvm.org/D37899https://bugs.llvm.org/show_bug.cgi?id=34610
llvm-svn: 314516
The expensive-checks build bot found a problem with the r314428 commit:
if CC is live after a ATOMIC_CMP_SWAPW instruction, it needs to be
marked as live-in to the block after the loop the pseudo gets expanded
to. This actually fixes a code-gen bug as well, since if the CC isn't
live, the CR and JLH are merged to a CRJLH which doesn't actually set
the condition code any more.
llvm-svn: 314465
The SystemZ compare-and-swap instructions already provide the "success"
indication via a condition-code value, so the default expansion of those
operations generates an unnecessary extra comparsion.
llvm-svn: 314428
More conversions to load-and-test can be made with this patch by adding a
forward search in optimizeCompareZero().
Review: Ulrich Weigand
https://reviews.llvm.org/D38076
llvm-svn: 313877
SystemZTargetLowering::combineSTORE contains code to transform a
combination of STORE + BSWAP into a STRV type instruction.
This transformation is correct for regular stores, but not for
truncating stores. The routine neglected to check for that case.
Fixes a miscompilation of llvm-objcopy with clang, which caused
test suite failures in the SystemZ multistage build bot.
llvm-svn: 313669
This bit is needed in order for the CalleeSavedRegs list to automatically
include the super registers if all of their subregs are present.
Thanks to Wei Mi for initially indicating this deficiency in the SystemZ
backend.
Review: Ulrich Weigand.
https://bugs.llvm.org/show_bug.cgi?id=34550
llvm-svn: 313023
The idea of this patch is to continue the scheduler state over an MBB boundary
in the case where the successor block has only one predecessor. This means
that the scheduler will continue in the successor block (after emitting any
branch instructions) with e.g. maintained processor resource counters.
Benchmarks have been confirmed to benefit from this.
The algorithm in MachineScheduler.cpp that extracts scheduling regions of an
MBB has been extended so that the strategy may optionally reverse the order
of processing the regions themselves. This is controlled by a new method
doMBBSchedRegionsTopDown(), which defaults to false.
Handling the top-most region of an MBB first also means that a top-down
scheduler can continue the scheduler state across any scheduling boundary
between to regions inside MBB.
Review: Ulrich Weigand, Matthias Braun, Andy Trick.
https://reviews.llvm.org/D35053
llvm-svn: 311072
Summary:
This fixes PR32721 in IfConvertTriangle and possible similar problems in
IfConvertSimple, IfConvertDiamond and IfConvertForkedDiamond.
In PR32721 we had a triangle
EBB
| \
| |
| TBB
| /
FBB
where FBB didn't have any successors at all since it ended with an
unconditional return. Then TBB and FBB were be merged into EBB, but EBB
would still keep its successors, and the use of analyzeBranch and
CorrectExtraCFGEdges wouldn't help to remove them since the return
instruction is not analyzable (at least not on ARM).
The edge updating code and branch probability updating code is now pushed
into MergeBlocks() which allows us to share the same update logic between
more callsites. This lets us remove several dependencies on analyzeBranch
and completely eliminate RemoveExtraEdges.
One thing that showed up with this patch was that IfConversion sometimes
left a successor with 0% probability even if there was no branch or
fallthrough to the successor.
One such example from the test case ifcvt_bad_zero_prob_succ.mir. The
indirect branch tBRIND can only jump to bb.1, but without the patch we
got:
bb.0:
successors: %bb.1(0x80000000)
bb.1:
successors: %bb.1(0x80000000), %bb.2(0x00000000)
tBRIND %r1, 1, %cpsr
B %bb.1
bb.2:
There is no way to jump from bb.1 to bb2, but still there is a 0% edge
from bb.1 to bb.2.
With the patch applied we instead get the expected:
bb.0:
successors: %bb.1(0x80000000)
bb.1:
successors: %bb.1(0x80000000)
tBRIND %r1, 1, %cpsr
B %bb.1
Since bb.2 had no predecessor at all, it was removed.
Several testcases had to be updated due to this since the removed
successor made the "Branch Probability Basic Block Placement" pass
sometimes place blocks in a different order.
Finally added a couple of new test cases:
* PR32721_ifcvt_triangle_unanalyzable.mir:
Regression test for the original problem dexcribed in PR 32721.
* ifcvt_triangleWoCvtToNextEdge.mir:
Regression test for problem that caused a revert of my first attempt
to solve PR 32721.
* ifcvt_simple_bad_zero_prob_succ.mir:
Test case showing the problem where a wrong successor with 0% probability
was previously left.
* ifcvt_[diamond|forked_diamond|simple]_unanalyzable.mir
Very simple test cases for the simple and (forked) diamond cases
involving unanalyzable branches that can be nice to have as a base if
wanting to write more complicated tests.
Reviewers: iteratee, MatzeB, grosser, kparzysz
Reviewed By: kparzysz
Subscribers: kbarton, davide, aemerson, nemanjai, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D34099
llvm-svn: 310697
The root cause of reverting was fixed - PR33514.
Summary:
The patch makes instruction count the highest priority for
LSR solution for X86 (previously registers had highest priority).
Reviewers: qcolombet
Differential Revision: http://reviews.llvm.org/D30562
From: Evgeny Stupachenko <evstupac@gmail.com>
<evgeny.v.stupachenko@intel.com>
llvm-svn: 310289
This adds support for the main 128-bit atomic operations,
using the SystemZ instructions LPQ, STPQ, and CDSG.
Generating these instructions is a bit more complex than usual
since the i128 type is not legal for the back-end. Therefore,
we have to hook the LowerOperationWrapper and ReplaceNodeResults
TargetLowering callbacks.
llvm-svn: 310094
We currently emit a serialization operation (bcr 14, 0) before every
atomic load and after every atomic store. This is overly conservative.
The SystemZ architecture actually does not require any serialization
for atomic loads, and a serialization after an atomic store only if
we need to enforce sequential consistency. This is what other compilers
for the platform implement as well.
llvm-svn: 310093
This patch makes LSR generate better code for SystemZ in the cases of memory
intrinsics, Load->Store pairs or comparison of immediate with memory.
In order to achieve this, the following common code changes were made:
* New TTI hook: LSRWithInstrQueries(), which defaults to false. Controls if
LSR should do instruction-based addressing evaluations by calling
isLegalAddressingMode() with the Instruction pointers.
* In LoopStrengthReduce: handle address operands of memset, memmove and memcpy
as address uses, and call isFoldableMemAccessOffset() for any LSRUse::Address,
not just loads or stores.
SystemZ changes:
* isLSRCostLess() implemented with Insns first, and without ImmCost.
* New function supportedAddressingMode() that is a helper for TTI methods
looking at Instructions passed via pointers.
Review: Ulrich Weigand, Quentin Colombet
https://reviews.llvm.org/D35262https://reviews.llvm.org/D35049
llvm-svn: 308729
This adds support for the new 128-bit vector float instructions of z14.
Note that these instructions actually only operate on the f128 type,
since only each 128-bit vector register can hold only one 128-bit
float value. However, this is still preferable to the legacy 128-bit
float instructions, since those operate on pairs of floating-point
registers (so we can hold at most 8 values in registers), while the
new instructions use single vector registers (so we hold up to 32
value in registers).
Adding support includes:
- Enabling the instructions for the assembler/disassembler.
- CodeGen for the instructions. This includes allocating the f128
type now to the VR128BitRegClass instead of FP128BitRegClass.
- Scheduler description support for the instructions.
Note that for a small number of operations, we have no new vector
instructions (like integer <-> 128-bit float conversions), and so
we use the legacy instruction and then reformat the operand
(i.e. copy between a pair of floating-point registers and a
vector register).
llvm-svn: 308196
This adds support for the new 32-bit vector float instructions of z14.
This includes:
- Enabling the instructions for the assembler/disassembler.
- CodeGen for the instructions, including new LLVM intrinsics.
- Scheduler description support for the instructions.
- Update to the vector cost function calculations.
In general, CodeGen support for the new v4f32 instructions closely
matches support for the existing v2f64 instructions.
llvm-svn: 308195
This patch series adds support for the IBM z14 processor. This part includes:
- Basic support for the new processor and its features.
- Support for new instructions (except vector 32-bit float and 128-bit float).
- CodeGen for new instructions, including new LLVM intrinsics.
- Scheduler description for the new processor.
- Detection of z14 as host processor.
Support for the new 32-bit vector float and 128-bit vector float
instructions is provided by separate patches.
llvm-svn: 308194
When reusing a register for a new definition, the fast register allocator
used to insert a kill flag at the previous last use of that register to
inform later passes that this register is free between the redef and the
last use. However, this may be wrong when subregisters are involved.
Indeed, a partially redef would have trigger a kill of the full super
register, potentially wrongly marking all the other subregisters as
free. Given we don't track which lanes are still live, we cannot set the
kill flag in such case.
Note: This bug has been latent for about 7 years (r104056).
llvmg.org/PR33677
llvm-svn: 307428
Krzysztof Parzyszek