Keep a bitvector of physical registers with a recorded def or use in
the current block. Register mask handling, the end of block scan, and
the per-block reset now only visit those registers instead of every
register. This is significant for targets with many registers, such as
AMDGPU.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
No physical register is tracked at the start of a block, so handling the
block live-ins was a no-op. The Defs list was only appended for
instruction defs, which runOnInstr already collects.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
This analysis is dead and there are no more explicit uses. There are still
passes implicitly relying on adjustments of dead flags. Missing dead
flags are added, and implicit-def operands are added for partially dead
physical registers.
The whole pass should be deleted, but it's taking a while to get all the
dead flag changes through the rest of the compiler. As a stop-gap to try to
recover some compile time regression, and avoiding new users appearing, strip
the pass down to only computing the dead flags.
The main side effect of this is kill flags are no longer made accurate, which
is the source of the test churn.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
LiveVariables::replaceKillInstruction: The last caller was removed on
October 1, 2026 in commit 8068182dd6.
TargetLoweringBase::getSupportedLibcallImpl: The last caller was
removed on October 24, 2025 in commit
26450db480.
Assisted-by: Antigravity
A reasonable number of places check getVRegDef just to
return the parent block, so introduce a helper for it.
Co-authored-by: Claude (Claude-Opus-4.8) <noreply@anthropic.com>
- Remove pass initialization calls from pass constructors.
- For some passes, add the initialization to `initializeCodeGen` or
`initializeGlobalISel`.
- Remove redundant initializations from llc and X86 target for some
passes.
LiveVariables will mark instructions with their implicit subregister
uses. However, it will also mark the subregister as an implicit if its
own definition is a subregister of it, i.e. `$r3 = OP val, implicit-def
$r0_r1_r2_r3, ..., implicit $r2_r3`, even if it is otherwise unused,
which defines $r3 on the same line it is used.
This change ensures such uses are marked without implicit, i.e. `$r3 =
OP val, implicit-def $r0_r1_r2_r3, ..., $r2_r3`.
---------
Co-authored-by: Matt Arsenault <arsenm2@gmail.com>
These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
Fixes#82659
There are some functions, such as `findRegisterDefOperandIdx` and `findRegisterDefOperand`, that have too many default parameters. As a result, we have encountered some issues due to the lack of TRI parameters, as shown in issue #82411.
Following @RKSimon 's suggestion, this patch refactors 9 functions, including `{reads, kills, defines, modifies}Register`, `registerDefIsDead`, and `findRegister{UseOperandIdx, UseOperand, DefOperandIdx, DefOperand}`, adjusting the order of the TRI parameter and making it required. In addition, all the places that call these functions have also been updated correctly to ensure no additional impact.
After this, the caller of these functions should explicitly know whether to pass the `TargetRegisterInfo` or just a `nullptr`.
* Introduce field `PositionOrder` for class `Register` and
`RegisterTuples`
* If register A's `PositionOrder` < register B's `PositionOrder`, then A
is placed before B in the enum in X86GenRegisterInfo.inc
* The new order of registers in the enum for X86 will be
1. Registers before AVX512,
2. AVX512 registers (X/YMM16-31, ZMM0-31, K registers)
3. AMX registers (TMM)
4. APX registers (R16-R31)
* Add a new target hook `getNumSupportedRegs()` to return the number of
registers for the function (may overestimate).
* Replace `getNumRegs()` with `getNumSupportedRegs()` in LiveVariables
to eliminate iterations on unsupported registers
This patch can reduce 0.3% instruction count regression for sqlite3
during compile-stage (O3) by not iterating on APX registers
for #67702
The last use of isPHIJoin was removed by:
commit fac770b865
Author: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Sat Feb 9 00:04:07 2013 +0000
so there is no reason to maintain PHIJoins.
A register's use with isUndef flags shouldn't be considered as a point where the register is live. LiveVariables::runOnInstr ignores such uses.
This was found when I tried to replace calls to
SIOptimizeVGPRLiveRange::updateLiveRangeInThenRegion
SIOptimizeVGPRLiveRange::updateLiveRangeInElseRegion
with LiveVariables::recomputeForSingleDefVirtReg.
In the testcase below %2 use is undef in the last REG_SEQUENCE.
CodeGen/AMDGPU/si-opt-vgpr-liverange-bug-deadlanes.mir failed:
Function Live Ins: $vgpr0 in %0
bb.0:
successors: %bb.1(0x40000000), %bb.2(0x40000000); %bb.1(50.00%), %bb.2(50.00%)
liveins: $vgpr0
%0:vgpr_32 = COPY killed $vgpr0
%1:vgpr_32 = V_MOV_B32_e32 0, implicit $exec
%2:vgpr_32 = BUFFER_LOAD_DWORD_OFFEN killed %0:vgpr_32, undef %5:sgpr_128, 0, 0, 0, 0, implicit $exec :: (dereferenceable invariant load (s32))
%3:sreg_64 = V_CMP_NE_U32_e64 0, %2:vgpr_32, implicit $exec
%7:sreg_64 = SI_IF killed %3:sreg_64, %bb.2, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
S_BRANCH %bb.1
bb.1:
; predecessors: %bb.0
successors: %bb.2(0x80000000); %bb.2(100.00%)
%8:vreg_128 = REG_SEQUENCE killed %1:vgpr_32, %subreg.sub0, %1:vgpr_32, %subreg.sub1, %1:vgpr_32, %subreg.sub2, undef %4.sub3:vreg_128, %subreg.sub3
bb.2:
; predecessors: %bb.0, %bb.1
successors: %bb.3(0x40000000), %bb.4(0x40000000); %bb.3(50.00%), %bb.4(50.00%)
%9:vreg_128 = PHI undef %10:vreg_128, %bb.0, %8:vreg_128, %bb.1
%14:vgpr_32 = PHI %2:vgpr_32, %bb.0, undef %15:vgpr_32, %bb.1
%11:sreg_64 = SI_ELSE killed %7:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
S_BRANCH %bb.3
bb.3:
; predecessors: %bb.2
successors: %bb.4(0x80000000); %bb.4(100.00%)
%12:vreg_128 = REG_SEQUENCE killed %14:vgpr_32, %subreg.sub0, %14:vgpr_32, %subreg.sub1, %14:vgpr_32, %subreg.sub2, undef %6:vgpr_32, %subreg.sub3
bb.4:
; predecessors: %bb.2, %bb.3
%13:vreg_128 = PHI %9:vreg_128, %bb.2, %12:vreg_128, %bb.3
SI_END_CF killed %11:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
dead %4:vreg_128 = REG_SEQUENCE killed %13.sub2:vreg_128, %subreg.sub0, %13.sub2:vreg_128, %subreg.sub1, %13.sub2:vreg_128, %subreg.sub2, **undef %2:vgpr_32**, %subreg.sub3
S_ENDPGM 0
*** Bad machine code: LiveVariables: Block should not be in AliveBlocks ***
- function: _amdgpu_ps_main
- basic block: %bb.1 (0x55e17ebd7100)
Virtual register %2 is not needed live through the block.
*** Bad machine code: LiveVariables: Block should not be in AliveBlocks ***
- function: _amdgpu_ps_main
- basic block: %bb.2 (0x55e17ebd7200)
Virtual register %2 is not needed live through the block.
*** Bad machine code: LiveVariables: Block should not be in AliveBlocks ***
- function: _amdgpu_ps_main
- basic block: %bb.3 (0x55e17ebd7300)
Virtual register %2 is not needed live through the block.
Differential Revision: https://reviews.llvm.org/D158167
This is a helper function to very slightly simplify many calls to
MachineInstruction::getOperandNo.
Differential Revision: https://reviews.llvm.org/D143250
Pseudo probe are currently given a slot index like other regular instructions. This affects register pressure and lifetime weight computation because of enlarged lifetime length with pseudo probe instructions. As a consequence, program could get different code generated w/ and w/o pseudo probes. I'm closing the gap by excluding pseudo probes from stack index and downstream register allocation related passes.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D100334
Replace std::vector with SmallVector to reduce the number of mallocs.
This method is frequently executed, and the number of elements in the
vector is typically small.
https://reviews.llvm.org/D83920
Summary:
In the patch D73152, it adds a new function LiveVariables::addNewBlock.
This new function will add the reg which PHI used to the MBB which reg
is from.
But the new function may cause LiveVariable Verification failed when the
Src reg in PHI is undef.
Reviewed By: bjope
Differential Revision: https://reviews.llvm.org/D80077
This is a compile-time optimization for PHIElimination (splitting of critical
edges), which was reported at https://bugs.llvm.org/show_bug.cgi?id=44249. As
discussed there, the way to remedy the slowdowns with huge functions is to
pre-compute the live-in registers for each MBB in an efficient way in
PHIElimination.cpp and then pass that information along to
LiveVariabless::addNewBlock().
In all the huge test programs where this slowdown has been noticable, it has
dissapeared entirely with this patch.
Review: Björn Pettersson, Quentin Colombet.
Differential Revision: https://reviews.llvm.org/D73152
MachineInstr.h included AliasAnalysis.h, which includes a world of IR
constructs mostly unneeded in CodeGen. Prune it. Same for
DebugInfoMetadata.h.
Noticed with -ftime-trace.
llvm-svn: 375311
Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).
Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor
Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&
Depends on D65919
Reviewers: arsenm, bogner, craig.topper, RKSimon
Reviewed By: arsenm
Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65962
llvm-svn: 369041
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Because we create a new kind of debug instruction, DBG_LABEL, we need to
check all passes which use isDebugValue() to check MachineInstr is debug
instruction or not. When expelling debug instructions, we should expel
both DBG_VALUE and DBG_LABEL. So, I create a new function,
isDebugInstr(), in MachineInstr to check whether the MachineInstr is
debug instruction or not.
This patch has no new test case. I have run regression test and there is
no difference in regression test.
Differential Revision: https://reviews.llvm.org/D45342
Patch by Hsiangkai Wang.
llvm-svn: 331844
See r331124 for how I made a list of files missing the include.
I then ran this Python script:
for f in open('filelist.txt'):
f = f.strip()
fl = open(f).readlines()
found = False
for i in xrange(len(fl)):
p = '#include "llvm/'
if not fl[i].startswith(p):
continue
if fl[i][len(p):] > 'Config':
fl.insert(i, '#include "llvm/Config/llvm-config.h"\n')
found = True
break
if not found:
print 'not found', f
else:
open(f, 'w').write(''.join(fl))
and then looked through everything with `svn diff | diffstat -l | xargs -n 1000 gvim -p`
and tried to fix include ordering and whatnot.
No intended behavior change.
llvm-svn: 331184
