operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&. At this point they almost behave like normal iterators!
Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.
llvm-svn: 203865
Without this, MachineCSE is powerless to handle redundant operations with truncated source operands.
This required fixing the 2-addr pass to handle tied subregisters. It isn't clear what combinations of subregisters can legally be tied, but the simple case of truncated source operands is now safely handled:
%vreg11<def> = COPY %vreg1:sub_32bit; GR32:%vreg11 GR64:%vreg1
%vreg12<def> = COPY %vreg2:sub_32bit; GR32:%vreg12 GR64:%vreg2
%vreg13<def,tied1> = ADD32rr %vreg11<tied0>, %vreg12<kill>, %EFLAGS<imp-def>
Test case: cse-add-with-overflow.ll.
This exposed an existing bug in
PPCInstrInfo::commuteInstruction. Thanks to Rafael for the test case:
PowerPC/crash.ll.
llvm-svn: 197465
that it coalesces normal copies.
Without this, MachineCSE is powerless to handle redundant operations
with truncated source operands.
This required fixing the 2-addr pass to handle tied subregisters. It
isn't clear what combinations of subregisters can legally be tied, but
the simple case of truncated source operands is now safely handled:
%vreg11<def> = COPY %vreg1:sub_32bit; GR32:%vreg11 GR64:%vreg1
%vreg12<def> = COPY %vreg2:sub_32bit; GR32:%vreg12 GR64:%vreg2
%vreg13<def,tied1> = ADD32rr %vreg11<tied0>, %vreg12<kill>, %EFLAGS<imp-def>
llvm-svn: 197414
The Segment struct contains a single interval; multiple instances of this struct
are used to construct a live range, but the struct is not a live range by
itself.
llvm-svn: 192392
at all of the operands. Previously it was skipping over implicit operands which
cause infinite looping when the two-address pass try to reschedule a
two-address instruction below the kill of tied operand.
I'm unable to come up with a reasonably sized test case.
rdar://13747577
llvm-svn: 180906
When MachineScheduler is enabled, this functionality can be
removed. Until then, provide a way to disable it for test cases and
designing MachineScheduler heuristics.
llvm-svn: 180192
itself recursively with a new instruction that has not been finalized, in order
to determine whether to keep the instruction. On 'make check' and test-suite the
only cases where the recursive invocation made any transformations were simple
instruction commutations, so I am restricting the recursive invocation to do
only this.
The other cases wouldn't work correctly when updating LiveIntervals, since the
new instructions don't have slot indices and LiveIntervals hasn't yet been
updated. If the other transformations were actually triggering in any test case
it would be possible to support it with a lot of effort, but since they don't
it's not worth it.
llvm-svn: 175979
unless it was requested to with an optional parameter that defaults to false, so
we don't need to handle that case in TwoAddressInstructionPass.
llvm-svn: 175974
TwoAddressInstructionPass. The code in rescheduleMIBelowKill() is a bit tricky,
since multiple instructions need to be moved down, one-at-a-time, in reverse
order.
llvm-svn: 175955
pass. One of the callers of isKilled() can cope with overapproximation of kills
and the other can't, so I added a flag to indicate this.
In theory this could pessimize code slightly, but in practice most physical
register uses are kills, and most important kills of physical registers are the
only uses of that register prior to register allocation, so we can recognize
them as kills even without kill flags.
This is relevant because LiveIntervals gets rid of all kill flags.
llvm-svn: 175821
available.
With this commit there are no longer any assertion or verifier failures when
running 'make check' without LiveVariables. There are still 56 failing tests
with codegen differences and 1 unexpectedly passing test.
llvm-svn: 175719
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.
There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.
The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.
I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).
I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.
llvm-svn: 171366
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
The TwoAddressInstructionPass takes the machine code out of SSA form by
expanding REG_SEQUENCE instructions into copies. It is no longer
necessary to rewrite the registers used by a REG_SEQUENCE instruction
because the new coalescer algorithm can do it now.
REG_SEQUENCE is just converted to a sequence of sub-register copies now.
llvm-svn: 169067
These extra operands are not needed by register allocators using
VirtRegRewriter, and RAFast don't need them any longer.
By omitting the <imp-def> operands, it becomes possible for the new
register coalescer to track which lanes are valid and which are undef.
llvm-svn: 164073
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.
llvm-svn: 161794
It is redundant; RegisterCoalescer will do the remat if it can't eliminate
the copy. Collected instruction counts before and after this. A few extra
instructions are generated due to spilling but it is normal to see these kinds
of changes with almost any small codegen change, according to Jakob.
This also fixed rdar://11830760 where xor is expected instead of movi0.
llvm-svn: 160749
LiveIntervals due to the two-addr pass generating bogus MI code.
The crux of the issue was a loop nesting problem. The intent of the code
which attempts to transform instructions before converting them to
two-addr form is to defer and reprocess any transformed instructions as
the second processing is likely to have more opportunities to coalesce
copies, etc. Unfortunately, there was one section of processing that was
not deferred -- the INSERT_SUBREG rewriting. Due to quirks of how this
rewriting proceeded, not only did it occur early, it removed the bits of
information needed for the deferred processing to correctly generate the
necessary two address form (specifically inserting a copy), but didn't
trigger any immediate assertions and produced what appeared to be
already valid two-address from code. Thus, the assertion only fired much
later in the pipeline.
The fix is to hoist the transformation logic up layer to where it can
more firmly defer all further processing, and to teach the normal
processing to handle an edge case previously handled as part of the
transformation logic. This edge case (already matched tied register
operands) needs to *not* defer any steps.
As has been brought up repeatedly in the process: wow does this code
need refactoring. I *may* squeeze in some time to at least bring sanity
to this loop... but wow... =]
Thanks to Jakob for helpful hints on the way here, and the review.
llvm-svn: 160443
The notable fix is to look at any dependencies attached to the kill
instruction (or other instructions between MI nad the kill) where the
dependencies are specific to the register in question.
The old code implicitly handled this by rejecting the transform if *any*
other uses were found within the block, but after the start point. The
new code directly finds the kill, and has to re-use the existing
dependency scan to check for non-kill uses.
This was caught by self-host, but I found the bug via inspection and use
of absurd assert scaffolding to compute the kills in two ways and
compare them. So I have no useful testcase for this other than
"bootstrap". I'd work harder to reduce a test case if this particular
code were likely to live for a long time.
Thanks to Benjamin Kramer for reviewing the fix itself.
llvm-svn: 160228
removes the largest scaling problem in the test cases from PR13225 when
ASan is switched to insert basic blocks in the natural CFG order.
It may also solve some scaling problems for more normal code with large
numbers of basic blocks and variables.
llvm-svn: 160194
When the source register to a 2-addr instruction is undefined, there is
no need to attempt any transformations - simply replace the source
register with the destination register.
This also comes up when lowering IMPLICIT_DEF instructions - make sure
the <undef> flag is moved to the new partial register def operand:
%vreg8<def> = INSERT_SUBREG %vreg9<undef>, %vreg0<kill>, sub_16bit
rewrite undef:
%vreg8<def> = INSERT_SUBREG %vreg8<undef>, %vreg0<kill>, sub_16bit
convert to:
%vreg8:sub_16bit<def,read-undef> = COPY %vreg0<kill>
llvm-svn: 159120
non-profitable commute using outdated info. The test case would still fail
because of poor pre-RA schedule. That will be fixed by MI scheduler.
rdar://11472010
llvm-svn: 157038
The getPointerRegClass() hook can return register classes that depend on
the calling convention of the current function (ptr_rc_tailcall).
So far, we have been able to infer the calling convention from the
subtarget alone, but as we add support for multiple calling conventions
per target, that no longer works.
Patch by Yiannis Tsiouris!
llvm-svn: 156328
to catch cases like:
%reg1024<def> = MOV r1
%reg1025<def> = MOV r0
%reg1026<def> = ADD %reg1024, %reg1025
r0 = MOV %reg1026
By commuting ADD, it let coalescer eliminate all of the copies. However, there
was a bug in the heuristics where it ended up commuting the ADD in:
%reg1024<def> = MOV r0
%reg1025<def> = MOV 0
%reg1026<def> = ADD %reg1024, %reg1025
r0 = MOV %reg1026
That did no benefit but rather ensure the last MOV would not be coalesced.
rdar://11355268
llvm-svn: 156048
The ensures that virtual registers always belong to an allocatable class.
If your target attempts to create a vreg for an operand that has no
allocatable register subclass, you will crash quickly.
This ensures that targets define register classes as intended.
llvm-svn: 156046
This patch restores TwoAddressInstructionPass's pre-r153892 behaviour when
rescheduling instructions in TryInstructionTransform. Hopefully this will fix
PR12493. To refix PR11861, lowering of INSERT_SUBREGS is deferred until after
the copy that unties the operands is emitted (this seems to be a more
appropriate fix for that issue anyway).
llvm-svn: 154338
Creates a configurable regalloc pipeline.
Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa.
When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>.
CodeGen transformation passes are never "required" as an analysis
ProcessImplicitDefs does not require LiveVariables.
We have a plan to massively simplify some of the early passes within the regalloc superpass.
llvm-svn: 150226
A REG_SEQUENCE instruction is lowered into a sequence of partial defs:
%vreg7:ssub_0<def,undef> = COPY %vreg20:ssub_0
%vreg7:ssub_1<def> = COPY %vreg2
%vreg7:ssub_2<def> = COPY %vreg2
%vreg7:ssub_3<def> = COPY %vreg2
The first def needs an <undef> flag to indicate it is the beginning of
the live range, while the other defs are read-modify-write. Previously,
we depended on LiveIntervalAnalysis to notice and fix the missing
<def,undef>, but that solution was never robust, it was causing problems
with ProcessImplicitDefs and the lowering of chained REG_SEQUENCE
instructions.
This fixes PR11841.
llvm-svn: 148879
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.
For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.
llvm-svn: 146026
"kill". This looks like a bug upstream. Since that's going to take some time
to understand, loosen the assertion and disable the optimization when
multiple kills are seen.
llvm-svn: 144568
instructions of the two-address operands) in order to avoid inserting copies.
This fixes the few regressions introduced when the two-address hack was
disabled (without regressing the improvements).
rdar://10422688
llvm-svn: 144559
This flag is true from isel to register allocation when the machine
function is required to be in SSA form. The TwoAddressInstructionPass
and PHIElimination passes clear the flag.
The SSA flag wil be used by the machine code verifier to check for SSA
form, and eventually an assertion can enforce it in +Asserts builds.
This will catch the common target error of creating machine code with
multiple defs of a virtual register.
llvm-svn: 136532
sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.
llvm-svn: 134021
Instead encode llvm IR level property "HasSideEffects" in an operand (shared
with IsAlignStack). Added MachineInstrs::hasUnmodeledSideEffects() to check
the operand when the instruction is an INLINEASM.
This allows memory instructions to be moved around INLINEASM instructions.
llvm-svn: 123044
alternative register allocator that does not require LiveIntervals by specifying
it on the command-line for a target that has StrongPHIElimination enabled by
default.
These checks are pretty meaningless anyways, since StrongPHIElimination and
PHIElimination are never used at the same time.
llvm-svn: 122176
regB = move RCX
regA = op regB, regC
RAX = move regA
where both regB and regC are killed. If regB is constrainted to non-compatible
physical registers but regC is not constrainted at all, then it's better to
commute the instruction.
movl %edi, %eax
shlq $32, %rcx
leaq (%rcx,%rax), %rax
=>
movl %edi, %eax
shlq $32, %rcx
orq %rcx, %rax
rdar://8762995
llvm-svn: 121793
Craig Topper