This behavior was added in r130928 for both FastISel and SD, and then
disabled in r131156 for FastISel.
This re-enables it for FastISel with the corresponding fix.
This is triggered only when FastISel can't lower the arguments and falls
back to SelectionDAG for it.
FastISel contains a map of "register fixups" where at the end of the
selection phase it replaces all uses of a register with another
register that FastISel sometimes pre-assigned. Code at the end of
SelectionDAGISel::runOnMachineFunction is doing the replacement at the
very end of the function, while other pieces that come in before that
look through the MachineFunction and assume everything is done. In this
case, the real issue is that the code emitting COPY instructions for the
liveins (physreg to vreg) (EmitLiveInCopies) is checking if the vreg
assigned to the physreg is used, and if it's not, it will skip the COPY.
If a register wasn't replaced with its assigned fixup yet, the copy will
be skipped and we'll end up with uses of undefined registers.
This fix moves the replacement of registers before the emission of
copies for the live-ins.
The initial motivation for this fix is to enable tail calls for
swiftself functions, which were blocked because we couldn't prove that
the swiftself argument (which is callee-save) comes from a function
argument (live-in), because there was an extra copy (vreg to vreg).
A few tests are affected by this:
* llvm/test/CodeGen/AArch64/swifterror.ll: we used to spill x21
(callee-save) but never reload it because it's attached to the return.
We now don't even spill it anymore.
* llvm/test/CodeGen/*/swiftself.ll: we tail-call now.
* llvm/test/CodeGen/AMDGPU/mubuf-legalize-operands.ll: I believe this
test was not really testing the right thing, but it worked because the
same registers were re-used.
* llvm/test/CodeGen/ARM/cmpxchg-O0.ll: regalloc changes
* llvm/test/CodeGen/ARM/swifterror.ll: get rid of a copy
* llvm/test/CodeGen/Mips/*: get rid of spills and copies
* llvm/test/CodeGen/SystemZ/swift-return.ll: smaller stack
* llvm/test/CodeGen/X86/atomic-unordered.ll: smaller stack
* llvm/test/CodeGen/X86/swifterror.ll: same as AArch64
* llvm/test/DebugInfo/X86/dbg-declare-arg.ll: stack size changed
Differential Revision: https://reviews.llvm.org/D62361
llvm-svn: 362963
This patch aims to reduce spilling and register moves by using the 3-address
versions of instructions per default instead of the 2-address equivalent
ones. It seems that both spilling and register moves are improved noticeably
generally.
Regalloc hints are passed to increase conversions to 2-address instructions
which are done in SystemZShortenInst.cpp (after regalloc).
Since the SystemZ reg/mem instructions are 2-address (dst and lhs regs are
the same), foldMemoryOperandImpl() can no longer trivially fold a spilled
source register since the reg/reg instruction is now 3-address. In order to
remedy this, new 3-address pseudo memory instructions are used to perform the
folding only when the dst and lhs virtual registers are known to be allocated
to the same physreg. In order to not let MachineCopyPropagation run and
change registers on these transformed instructions (making it 3-address), a
new target pass called SystemZPostRewrite.cpp is run just after
VirtRegRewriter, that immediately lowers the pseudo to a target instruction.
If it would have been possibe to insert a COPY instruction and change a
register operand (convert to 2-address) in foldMemoryOperandImpl() while
trusting that the caller (e.g. InlineSpiller) would update/repair the
involved LiveIntervals, the solution involving pseudo instructions would not
have been needed. This is perhaps a potential improvement (see Phabricator
post).
Common code changes:
* A new hook TargetPassConfig::addPostRewrite() is utilized to be able to run a
target pass immediately before MachineCopyPropagation.
* VirtRegMap is passed as an argument to foldMemoryOperand().
Review: Ulrich Weigand, Quentin Colombet
https://reviews.llvm.org/D60888
llvm-svn: 362868
The ISD::STRICT_ nodes used to implement the constrained floating-point
intrinsics are currently never passed to the target back-end, which makes
it impossible to handle them correctly (e.g. mark instructions are depending
on a floating-point status and control register, or mark instructions as
possibly trapping).
This patch allows the target to use setOperationAction to switch the action
on ISD::STRICT_ nodes to Legal. If this is done, the SelectionDAG common code
will stop converting the STRICT nodes to regular floating-point nodes, but
instead pass the STRICT nodes to the target using normal SelectionDAG
matching rules.
To avoid having the back-end duplicate all the floating-point instruction
patterns to handle both strict and non-strict variants, we make the MI
codegen explicitly aware of the floating-point exceptions by introducing
two new concepts:
- A new MCID flag "mayRaiseFPException" that the target should set on any
instruction that possibly can raise FP exception according to the
architecture definition.
- A new MI flag FPExcept that CodeGen/SelectionDAG will set on any MI
instruction resulting from expansion of any constrained FP intrinsic.
Any MI instruction that is *both* marked as mayRaiseFPException *and*
FPExcept then needs to be considered as raising exceptions by MI-level
codegen (e.g. scheduling).
Setting those two new flags is straightforward. The mayRaiseFPException
flag is simply set via TableGen by marking all relevant instruction
patterns in the .td files.
The FPExcept flag is set in SDNodeFlags when creating the STRICT_ nodes
in the SelectionDAG, and gets inherited in the MachineSDNode nodes created
from it during instruction selection. The flag is then transfered to an
MIFlag when creating the MI from the MachineSDNode. This is handled just
like fast-math flags like no-nans are handled today.
This patch includes both common code changes required to implement the
new features, and the SystemZ implementation.
Reviewed By: andrew.w.kaylor
Differential Revision: https://reviews.llvm.org/D55506
llvm-svn: 362663
[FPEnv] Added a special UnrollVectorOp method to deal with the chain on StrictFP opcodes
This change creates UnrollVectorOp_StrictFP. The purpose of this is to address a failure that consistently occurs when calling StrictFP functions on vectors whose number of elements is 3 + 2n on most platforms, such as PowerPC or SystemZ. The old UnrollVectorOp method does not expect that the vector that it will unroll will have a chain, so it has an assert that prevents it from running if this is the case. This new StrictFP version of the method deals with the chain while unrolling the vector. With this new function in place during vector widending, llc can run vector-constrained-fp-intrinsics.ll for SystemZ successfully.
Submitted by: Drew Wock <drew.wock@sas.com>
Reviewed by: Cameron McInally, Kevin P. Neal
Approved by: Cameron McInally
Differential Revision: https://reviews.llvm.org/D62546
llvm-svn: 362241
Summary:
Direct sibling of D62223 patch.
While i don't have a direct motivational pattern for this,
it would seem to make sense to handle both patterns (or none),
for symmetry?
The aarch64 changes look neutral;
sparc and systemz look like improvement (one less instruction each);
x86 changes - 32bit case improves, 64bit case shows that LEA no longer
gets constructed, which may be because that whole test is `-mattr=+slow-lea,+slow-3ops-lea`
https://rise4fun.com/Alive/ffh
This is a recommit, originally committed in rL361852, but reverted
to investigate test-suite compile-time hangs, and then reverted in
rL362109 to fix missing constant folds that were causing
endless combine loops.
Reviewers: RKSimon, craig.topper, spatel, t.p.northover
Reviewed By: t.p.northover
Subscribers: t.p.northover, jyknight, javed.absar, kristof.beyls, fedor.sergeev, jrtc27, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62252
llvm-svn: 362143
This change creates UnrollVectorOp_StrictFP. The purpose of this is to address a failure that consistently occurs when calling StrictFP functions on vectors whose number of elements is 3 + 2n on most platforms, such as PowerPC or SystemZ. The old UnrollVectorOp method does not expect that the vector that it will unroll will have a chain, so it has an assert that prevents it from running if this is the case. This new StrictFP version of the method deals with the chain while unrolling the vector. With this new function in place during vector widending, llc can run vector-constrained-fp-intrinsics.ll for SystemZ successfully.
Submitted by: Drew Wock <drew.wock@sas.com>
Reviewed by: Cameron McInally, Kevin P. Neal
Approved by: Cameron McInally
Differential Revision: http://reviews.llvm.org/D62546
llvm-svn: 362112
I was looking into an endless combine loop the uncommitted follow-up patch
was causing, and it appears even these patches can exibit such an
endless loop. The root cause is that we try to hoist one binop (add/sub) with
constant operand, and if we get two such binops both of which are
eligible for this hoisting, we get stuck.
Some cases may highlight missing constant-folds.
Reverts r361871,r361872,r361873,r361874.
llvm-svn: 362109
Summary:
Direct sibling of D62223 patch.
While i don't have a direct motivational pattern for this,
it would seem to make sense to handle both patterns (or none),
for symmetry?
The aarch64 changes look neutral;
sparc and systemz look like improvement (one less instruction each);
x86 changes - 32bit case improves, 64bit case shows that LEA no longer
gets constructed, which may be because that whole test is `-mattr=+slow-lea,+slow-3ops-lea`
https://rise4fun.com/Alive/ffh
This is a recommit, originally committed in rL361853, but reverted
to investigate test-suite compile-time hangs.
Reviewers: RKSimon, craig.topper, spatel, t.p.northover
Reviewed By: t.p.northover
Subscribers: t.p.northover, jyknight, javed.absar, kristof.beyls, fedor.sergeev, jrtc27, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62252
llvm-svn: 361872
Summary:
Direct sibling of D62223 patch.
While i don't have a direct motivational pattern for this,
it would seem to make sense to handle both patterns (or none),
for symmetry?
The aarch64 changes look neutral;
sparc and systemz look like improvement (one less instruction each);
x86 changes - 32bit case improves, 64bit case shows that LEA no longer
gets constructed, which may be because that whole test is `-mattr=+slow-lea,+slow-3ops-lea`
https://rise4fun.com/Alive/ffh
Reviewers: RKSimon, craig.topper, spatel, t.p.northover
Reviewed By: t.p.northover
Subscribers: t.p.northover, jyknight, javed.absar, kristof.beyls, fedor.sergeev, jrtc27, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62252
llvm-svn: 361853
Make sure to not unroll a vector division/remainder (with a constant splat
divisor) after type legalization, since the scalar type may then be illegal.
Review: Ulrich Weigand
https://reviews.llvm.org/D62036
llvm-svn: 360965
This adds the FPC (floating-point control register) as a reserved
physical register and models its use by SystemZ instructions.
Note that only the current rounding modes and the IEEE exception
masks are modeled. *Changes* of the FPC due to exceptions (in
particular the IEEE exception flags and the DXC) are not modeled.
At this point, this patch is mostly NFC, but it will prevent
scheduling of floating-point instructions across SPFC/LFPC etc.
llvm-svn: 360570
Summary:
Extract the logic for doing reassociations
from DAGCombiner::reassociateOps into a helper
function DAGCombiner::reassociateOpsCommutative,
and use that helper to trigger reassociation
on the original operand order, or the commuted
operand order.
Codegen is not identical since the operand order will
be different when doing the reassociations for the
commuted case. That causes some unfortunate churn in
some test cases. Apart from that this should be NFC.
Reviewers: spatel, craig.topper, tstellar
Reviewed By: spatel
Subscribers: dmgreen, dschuff, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, hiraditya, aheejin, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61199
llvm-svn: 359476
Summary:
Targets like ARM, MSP430, PPC, and SystemZ have complex behavior when
printing the address of a MachineOperand::MO_GlobalAddress. Move that
handling into a new overriden method in each base class. A virtual
method was added to the base class for handling the generic case.
Refactors a few subclasses to support the target independent %a, %c, and
%n.
The patch also contains small cleanups for AVRAsmPrinter and
SystemZAsmPrinter.
It seems that NVPTXTargetLowering is possibly missing some logic to
transform GlobalAddressSDNodes for
TargetLowering::LowerAsmOperandForConstraint to handle with "i" extended
inline assembly asm constraints.
Fixes:
- https://bugs.llvm.org/show_bug.cgi?id=41402
- https://github.com/ClangBuiltLinux/linux/issues/449
Reviewers: echristo, void
Reviewed By: void
Subscribers: void, craig.topper, jholewinski, dschuff, jyknight, dylanmckay, sdardis, nemanjai, javed.absar, sbc100, jgravelle-google, eraman, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, jrtc27, atanasyan, jsji, llvm-commits, kees, tpimh, nathanchance, peter.smith, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60887
llvm-svn: 359337
Certain optimisations from ConstantHoisting and CGP rely on Selection DAG not
seeing through to the constant in other blocks. Revert this patch while we come
up with a better way to handle that.
I will try to follow this up with some better tests.
llvm-svn: 358113
This lines up with what we do for regular subtract and it matches up better with X86 assumptions in isel patterns that add with immediate is more canonical than sub with immediate.
Differential Revision: https://reviews.llvm.org/D60020
llvm-svn: 358027
Summary:
Teach SelectionDAG how to compute known bits of ISD::CopyFromReg if
the virtual reg used has one def only.
This can be particularly useful when calling isBaseWithConstantOffset()
with the ISD::CopyFromReg argument, as more optimizations may get enabled
in the result.
Also add a missing truncation on X86, found by testing of this patch.
Change-Id: Id1c9fceec862d118c54a5b53adf72ada5d6daefa
Reviewers: bogner, craig.topper, RKSimon
Reviewed By: RKSimon
Subscribers: lebedev.ri, nemanjai, jvesely, nhaehnle, javed.absar, jsji, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59535
llvm-svn: 357745
This function is responsible for checking the legality of fusing an instance
of load -> op -> store into a single operation. In the SystemZ backend the
check was incomplete and a test case emerged with a cycle in the instruction
selection DAG as a result.
Instead of using the NodeIds to determine node relationships,
hasPredecessorHelper() now is used just like in the X86 backend. This handled
the failing tests and as well gave a few additional transformations on
benchmarks.
The SystemZ isFusableLoadOpStorePattern() is now a very near copy of the X86
function, and it seems this could be made a utility function in common code
instead.
Review: Ulrich Weigand
https://reviews.llvm.org/D60255
llvm-svn: 357688
When performing an add-with-overflow with an immediate in the
range -2G ... -4G, code currently loads the immediate into a
register, which generally takes two instructions.
In this particular case, it is preferable to load the negated
immediate into a register instead, which always only requires
one instruction, and then perform a subtract.
llvm-svn: 357597
For shift and rotate instructions that only use the last 6 bits of the shift
amount, a shift amount of (x*64-s) can be substituted with (-s). This saves
one instruction and a register:
lhi %r1, 64
sr %r1, %r3
sllg %r2, %r2, 0(%r1)
=>
lcr %r1, %r3
sllg %r2, %r2, 0(%r1)
Review: Ulrich Weigand
llvm-svn: 357481
getAsCarry() checks that the input argument is a carry-producing node before
allowing a transformation to addcarry. This patch adds a check to make sure
that the carry-producing node is legal. If it is not, it may not remain in a
form that is manageable by the target backend. The test case caused a
compilation failure during instruction selection for this reason on SystemZ.
Patch by Ulrich Weigand.
Review: Sanjay Patel
https://reviews.llvm.org/D59822
llvm-svn: 357052
When splitting a subrange we end up with two different subranges covering
two different, non overlapping, lanes.
As part of this splitting the VNIs of the original live-range need
to be dispatched to the subranges according to which lanes they are
actually defining.
Prior to this patch we were assuming that all values were defining
all lanes. This was wrong as demonstrated by llvm.org/PR40835.
Differential Revision: https://reviews.llvm.org/D59731
llvm-svn: 357032
The 2nd loop calculates spill costs but reports free registers as cost
0 anyway, so there is little benefit from having a separate early
loop.
Surprisingly this is not NFC, as many register are marked regDisabled
so the first loop often picks up later registers unnecessarily instead
of the first one available in the allocation order...
Patch by Matthias Braun
llvm-svn: 356499
This patch enables combining integer bitcasts of integer build vectors when the new scalar type is legal. I've avoided floating point because the implementation bitcasts float to int along the way and we would need to check the intermediate types for legality
Differential Revision: https://reviews.llvm.org/D58884
llvm-svn: 355324
Since there is no "Load-and-Test-High" instruction, the 32 bit load of a
register to be compared with 0 can only be implemented with LT if the virtual
GRX32 register ends up in a low part (GR32 register).
This patch detects these cases and passes the GR32 registers (low parts) as
(soft) hints in getRegAllocationHints().
Review: Ulrich Weigand.
llvm-svn: 354935
This patch aims to make sure that any such constant that can be generated
with a vector instruction (for example VGBM) is recognized as such during
legalization and kept as a target independent node through post-legalize
DAGCombining.
Two new functions named isVectorConstantLegal() and loadVectorConstant()
replace old ways of handling vector/FP constants.
A new struct named SystemZVectorConstantInfo is used to cache the results of
isVectorConstantLegal() and pass them onto loadVectorConstant().
Support for fp128 constants in the presence of FeatureVectorEnhancements1
(z14) has been added.
Review: Ulrich Weigand
https://reviews.llvm.org/D58270
llvm-svn: 354896
It seems there were some problem with using a .mir test. For some reason
doing '-stop-before=codegenprepare' and then '-start-before=codegenprepare'
on the output .mir file results in the NoVRegs Property after instruction
selection.
Recommitting the same test as an .ll file instead.
llvm-svn: 354160
isFPImmLegal() has been extended to recognize certain FP immediates that can
be built with VGM (Vector Generate Mask).
These scalar FP immediates (that were previously loaded from the constant
pool) are now selected as VGMF/VGMG in Select().
Review: Ulrich Weigand
https://reviews.llvm.org/D58003
llvm-svn: 353867
Since SystemZ supports counting of leading zeros with the FLOGR instruction,
isCheapToSpeculateCtlz() should return true, which it now does.
ISD::CTLZ_ZERO_UNDEF i32 is now handled the same way as ISD::CTLZ is, which
is needed since promotion to i64 is required and CTLZ_ZERO_UNDEF is only
expanded to CTLZ if it is Legal or Custom.
Review: Ulrich Weigand
https://reviews.llvm.org/D57710
llvm-svn: 353330
Don't lower BUILD_VECTORs to BYTE_MASK, but instead expose the BUILD_VECTORs
to the DAGCombiner and select them to VGBM in Select(). This allows the
DAGCombiner to understand the constant vector values.
For floating point, only all-zeros vectors are now generated with VGBM, as it
turned out to be somewhat complicated to handle any arbitrary constants,
while in practice this is very rare and hardly needed.
The SystemZ ISD opcodes z_byte_mask, z_vzero and z_vones have been removed.
Review: Ulrich Weigand
https://reviews.llvm.org/D57152
llvm-svn: 353325
The IPM sequence currently generated to compute the strcmp/memcmp
result will return INT_MIN for the "less than zero" case. While
this is in compliance with the standard, strictly speaking, it
turns out that common applications cannot handle this, e.g. because
they negate a comparison result in order to implement reverse
compares.
This patch changes code to use a different sequence that will result
in -2 for the "less than zero" case (same as GCC). However, this
requires that the two source operands of the compare instructions
are inverted, which breaks the optimization in removeIPMBasedCompare.
Therefore, I've removed this (and all of optimizeCompareInstr), and
replaced it with a mostly equivalent optimization in combineCCMask
at the DAGcombine level.
llvm-svn: 353304
This patch makes sure that a debug value that is after the bitcast in
dupRetToEnableTailCallOpts() is also skipped.
The reduced test case is from SPEC-2006 on SystemZ.
Review: Vedant Kumar, Wolfgang Pieb
https://reviews.llvm.org/D57050
llvm-svn: 352462
After creating new PHI instructions during isel pseudo expansion, the NoPHIs
property of MF should be reset in case it was previously set.
Review: Ulrich Weigand
llvm-svn: 352030
Two backend optimizations failed to handle cases when compiled with -g, due
to failing to consider DBG_VALUE instructions. This was in
SystemZTargetLowering::emitSelect() and
SystemZElimCompare::getRegReferences().
This patch makes sure that DBG_VALUEs are recognized so that they do not
affect these optimizations.
Tests for branch-on-count, load-and-trap and consecutive selects.
Review: Ulrich Weigand
https://reviews.llvm.org/D57048
llvm-svn: 351928
compiler identification lines in test-cases.
(Doing so only because it's then easier to search for references which
are actually important and need fixing.)
llvm-svn: 351200
Part of the effort to refactoring frame pointer code generation. We used
to use two function attributes "no-frame-pointer-elim" and
"no-frame-pointer-elim-non-leaf" to represent three kinds of frame
pointer usage: (all) frames use frame pointer, (non-leaf) frames use
frame pointer, (none) frame use frame pointer. This CL makes the idea
explicit by using only one enum function attribute "frame-pointer"
Option "-frame-pointer=" replaces "-disable-fp-elim" for tools such as
llc.
"no-frame-pointer-elim" and "no-frame-pointer-elim-non-leaf" are still
supported for easy migration to "frame-pointer".
tests are mostly updated with
// replace command line args ‘-disable-fp-elim=false’ with ‘-frame-pointer=none’
grep -iIrnl '\-disable-fp-elim=false' * | xargs sed -i '' -e "s/-disable-fp-elim=false/-frame-pointer=none/g"
// replace command line args ‘-disable-fp-elim’ with ‘-frame-pointer=all’
grep -iIrnl '\-disable-fp-elim' * | xargs sed -i '' -e "s/-disable-fp-elim/-frame-pointer=all/g"
Patch by Yuanfang Chen (tabloid.adroit)!
Differential Revision: https://reviews.llvm.org/D56351
llvm-svn: 351049
Use range instead of xrange whenever possible. The extra list creation in Python2
is generally not a performance bottleneck.
Differential Revision: https://reviews.llvm.org/D56253
llvm-svn: 350309
