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* Switch most getReservedRegs() clients to the MRI equivalent.Jakob Stoklund Olesen2012-10-15
| | | | | | | Using the cached bit vector in MRI avoids comstantly allocating and recomputing the reserved register bit vector. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165983 91177308-0d34-0410-b5e6-96231b3b80d8
* Switch all register list clients to the new MC*Iterator interface.Jakob Stoklund Olesen2012-06-01
| | | | | | | | | | | | | No functional change intended. Sorry for the churn. The iterator classes are supposed to help avoid giant commits like this one in the future. The TableGen-produced register lists are getting quite large, and it may be necessary to change the table representation. This makes it possible to do so without changing all clients (again). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157854 91177308-0d34-0410-b5e6-96231b3b80d8
* Simplify some more getAliasSet callers.Jakob Stoklund Olesen2012-06-01
| | | | | | MCRegAliasIterator can include Reg itself in the list. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157848 91177308-0d34-0410-b5e6-96231b3b80d8
* Add an MRI::tracksLiveness() flag.Jakob Stoklund Olesen2012-03-27
| | | | | | | | | | | | | | | | | | | | Late optimization passes like branch folding and tail duplication can transform the machine code in a way that makes it expensive to keep the register liveness information up to date. There is a fuzzy line between register allocation and late scheduling where the liveness information degrades. The MRI::tracksLiveness() flag makes the line clear: While true, liveness information is accurate, and can be used for register scavenging. Once the flag is false, liveness information is not accurate, and can only be used as a hint. Late passes generally don't need the liveness information, but they will sometimes use the register scavenger to help update it. The scavenger enforces strict correctness, and we have to spend a lot of code to update register liveness that may never be used. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153511 91177308-0d34-0410-b5e6-96231b3b80d8
* Convert more GenRegisterInfo tables from unsigned to uint16_t to reduce ↵Craig Topper2012-03-05
| | | | | | static data size. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152016 91177308-0d34-0410-b5e6-96231b3b80d8
* Use uint16_t to store register overlaps to reduce static data.Craig Topper2012-03-04
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152001 91177308-0d34-0410-b5e6-96231b3b80d8
* Use uint16_t to store registers in callee saved register tables to reduce ↵Craig Topper2012-03-04
| | | | | | size of static data. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151996 91177308-0d34-0410-b5e6-96231b3b80d8
* Track reserved registers separately from RegsAvailable.Jakob Stoklund Olesen2012-02-23
| | | | | | | The bulk masking operations from register mask operands don't account for reserved registers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151222 91177308-0d34-0410-b5e6-96231b3b80d8
* Handle regmasks in RegisterScavenging.Jakob Stoklund Olesen2012-02-22
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151210 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix some scavenger performance issues.Jakob Stoklund Olesen2012-01-29
| | | | | | | | | | | | | - Don't call malloc+free in the very hot forward(). - Don't call isTiedToDefOperand(). - Don't create BitVector temporaries. - Merge DeadRegs into KillRegs. - Eliminate the early clobber checks, they were irrelevant to scavenging. - Remove unnecessary code from -Asserts builds. This speeds up ARM PEI by 3.4x and overall llc -O0 codegen time by 11%. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149189 91177308-0d34-0410-b5e6-96231b3b80d8
* Avoid creating BitVector temporaries.Jakob Stoklund Olesen2012-01-29
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149188 91177308-0d34-0410-b5e6-96231b3b80d8
* Give better scavenger errors by invoking the verifier.Jakob Stoklund Olesen2012-01-16
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148251 91177308-0d34-0410-b5e6-96231b3b80d8
* Added a late machine instruction copy propagation pass. This catchesEvan Cheng2012-01-07
| | | | | | | | | | | | | | | | | | | | | | | | | | opportunities that only present themselves after late optimizations such as tail duplication .e.g. ## BB#1: movl %eax, %ecx movl %ecx, %eax ret The register allocator also leaves some of them around (due to false dep between copies from phi-elimination, etc.) This required some changes in codegen passes. Post-ra scheduler and the pseudo-instruction expansion passes have been moved after branch folding and tail merging. They were before branch folding before because it did not always update block livein's. That's fixed now. The pass change makes independently since we want to properly schedule instructions after branch folding / tail duplication. rdar://10428165 rdar://10640363 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147716 91177308-0d34-0410-b5e6-96231b3b80d8
* Silence a bunch (but not all) "variable written but not read" warningsDuncan Sands2011-08-12
| | | | | | | when building with assertions disabled. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137460 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert "Don't check liveness of unallocatable registers."Jakob Stoklund Olesen2011-07-30
| | | | | | | The ARM target depends on CPSR liveness being tracked after register allocation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136548 91177308-0d34-0410-b5e6-96231b3b80d8
* Don't check liveness of unallocatable registers.Jakob Stoklund Olesen2011-07-29
| | | | | | | | | | | | This includes registers like EFLAGS and ST0-ST7. We don't check for liveness issues in the verifier and scavenger because registers will never be allocated from these classes. While in SSA form, we do care about the liveness of unallocatable unreserved registers. Liveness of EFLAGS and ST0 neds to be correct for MachineDCE and MachineSinking. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136541 91177308-0d34-0410-b5e6-96231b3b80d8
* Handle <def,undef> in the second loop as well.Jakob Stoklund Olesen2011-05-02
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130718 91177308-0d34-0410-b5e6-96231b3b80d8
* Only ignore <undef> use operands, keep the <def,undef> ops.Jakob Stoklund Olesen2011-05-02
| | | | | | | | Def operands may also have an <undef> flag, but that just means that a sub-register redef doesn't actually read the super-register. For physical registers, it has no meaning. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130714 91177308-0d34-0410-b5e6-96231b3b80d8
* Add an assertion instead of crashing when the scavenger goes past the endBob Wilson2011-04-05
| | | | | | of a basic block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128925 91177308-0d34-0410-b5e6-96231b3b80d8
* Teach the register scavenger to take subregs into account when finding a ↵Jim Grosbach2011-03-05
| | | | | | free register. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127049 91177308-0d34-0410-b5e6-96231b3b80d8
* The scavenger should just use getAllocatableSet() rather than reinventing itJim Grosbach2010-09-02
| | | | | | locally. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112845 91177308-0d34-0410-b5e6-96231b3b80d8
* Add a bit of debug output for register scavengingJim Grosbach2010-09-02
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112787 91177308-0d34-0410-b5e6-96231b3b80d8
* Simplify eliminateFrameIndex() interface back down now that PEI doesn't needJim Grosbach2010-08-26
| | | | | | to try to re-use scavenged frame index reference registers. rdar://8277890 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112241 91177308-0d34-0410-b5e6-96231b3b80d8
* Clean up scavengeRegister() a bit to prefer available regs, which allowsJim Grosbach2010-07-08
| | | | | | | | the simplification of frame index register scavenging to not have to check for available registers directly and instead just let scavengeRegister() handle it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107880 91177308-0d34-0410-b5e6-96231b3b80d8
* When processing frame index virtual registers, consider all available registersJim Grosbach2010-07-08
| | | | | | | | | | (if there are any) and use the one which remains available for the longest rather than just using the first one. This should help enable better re-use of the loaded frame index values. rdar://7318760 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107847 91177308-0d34-0410-b5e6-96231b3b80d8
* Make post-ra scheduling, anti-dep breaking, and register scavenger ↵Evan Cheng2010-06-16
| | | | | | (conservatively) aware of predicated instructions. This enables ARM to move if-conversion before post-ra scheduler. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106091 91177308-0d34-0410-b5e6-96231b3b80d8
* Skip dbg_value instructions when scanning instructions in register scavenging.Jim Grosbach2010-06-04
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105481 91177308-0d34-0410-b5e6-96231b3b80d8
* Add argument TargetRegisterInfo to loadRegFromStackSlot and storeRegToStackSlot.Evan Cheng2010-05-06
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103193 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix PR6847. RegScavenger should ignore DebugValues.Jakob Stoklund Olesen2010-04-15
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101392 91177308-0d34-0410-b5e6-96231b3b80d8
* Eliminate MachineBasicBlock::const_livein_iterator and makeDan Gohman2010-04-13
| | | | | | | | | MachineBasicBlock::livein_iterator a const_iterator, because clients shouldn't ever be using the iterator interface to mutate the livein set. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101147 91177308-0d34-0410-b5e6-96231b3b80d8
* improve portability to avoid conflicting with std::next in c++'0x.Chris Lattner2009-12-03
| | | | | | | Patch by Howard Hinnant! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
* RegScavenger::enterBasicBlock should always reset register state.Evan Cheng2009-11-12
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86972 91177308-0d34-0410-b5e6-96231b3b80d8
* - Revert some changes from 85044, 85045, and 85047 that broke x86_64 tests andEvan Cheng2009-10-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | bootstrapping. It's not safe to leave identity subreg_to_reg and insert_subreg around. - Relax register scavenging to allow use of partially "not-live" registers. It's common for targets to operate on registers where the top bits are undef. e.g. s0 = d0 = insert_subreg d0<undef>, s0, 1 ... = d0 When the insert_subreg is eliminated by the coalescer, the scavenger used to complain. The previous fix was to keep to insert_subreg around. But that's brittle and it's overly conservative when we want to use the scavenger to allocate registers. It's actually legal and desirable for other instructions to use the "undef" part of d0. e.g. s0 = d0 = insert_subreg d0<undef>, s0, 1 ... s1 = = s1 = d0 We probably need add a "partial-undef" marker on machine operand so the machine verifier would not complain. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85091 91177308-0d34-0410-b5e6-96231b3b80d8
* When the scavenger is looking for a good candidate location to restore from aJim Grosbach2009-10-25
| | | | | | | spill, it should avoid doing so inside the live range of a virtual register. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85026 91177308-0d34-0410-b5e6-96231b3b80d8
* The spill restore needs to be resolved to the SP/FP just like the spillJim Grosbach2009-10-21
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84792 91177308-0d34-0410-b5e6-96231b3b80d8
* Adjust the scavenge register spilling to allow the target to choose anJim Grosbach2009-10-19
| | | | | | | | | | | | appropriate restore location for the spill as well as perform the actual save and restore. The Thumb1 target uses this to make sure R12 is not clobbered while a spilled scavenger register is live there. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84554 91177308-0d34-0410-b5e6-96231b3b80d8
* Add register-reuse to frame-index register scavenging. When a target usesJim Grosbach2009-10-07
| | | | | | | | | | | | | | | | | | | | | | a virtual register to eliminate a frame index, it can return that register and the constant stored there to PEI to track. When scavenging to allocate for those registers, PEI then tracks the last-used register and value, and if it is still available and matches the value for the next index, reuses the existing value rather and removes the re-materialization instructions. Fancier tracking and adjustment of scavenger allocations to keep more values live for longer is possible, but not yet implemented and would likely be better done via a different, less special-purpose, approach to the problem. eliminateFrameIndex() is modified so the target implementations can return the registers they wish to be tracked for reuse. ARM Thumb1 implements and utilizes the new mechanism. All other targets are simply modified to adjust for the changed eliminateFrameIndex() prototype. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83467 91177308-0d34-0410-b5e6-96231b3b80d8
* grammarJim Grosbach2009-10-06
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83378 91177308-0d34-0410-b5e6-96231b3b80d8
* In Thumb1, the register scavenger is not always able to use an emergencyJim Grosbach2009-10-05
| | | | | | | | | | spill slot. When frame references are via the frame pointer, they will be negative, but Thumb1 load/store instructions only allow positive immediate offsets. Instead, Thumb1 will spill to R12. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83336 91177308-0d34-0410-b5e6-96231b3b80d8
* replace TRI->isVirtualRegister() with TargetRegisterInfo::isVirtualRegister()Jim Grosbach2009-09-30
| | | | | | per customary usage git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83137 91177308-0d34-0410-b5e6-96231b3b80d8
* Additional check for regno==0Jim Grosbach2009-09-29
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83103 91177308-0d34-0410-b5e6-96231b3b80d8
* Moving register scavenging to a post pass results in virtual registers inJim Grosbach2009-09-29
| | | | | | | | | the instruction we're scavenging for. The scavenger needs to know to avoid them when analyzing register usage. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83077 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix PR5024 with a big hammer: disable the double-def assertion in the scavenger.Evan Cheng2009-09-24
| | | | | | | | | | | | | | | | | | | | | | | LiveVariables add implicit kills to correctly track partial register kills. This works well enough and is fairly accurate. But coalescer can make it impossible to maintain these markers. e.g. BL <ga:sss1>, %R0<kill,undef>, %S0<kill>, %R0<imp-def>, %R1<imp-def,dead>, %R2<imp-def,dead>, %R3<imp-def,dead>, %R12<imp-def,dead>, %LR<imp-def,dead>, %D0<imp-def>, ... ... %reg1031<def> = FLDS <cp#1>, 0, 14, %reg0, Mem:LD4[ConstantPool] ... %S0<def> = FCPYS %reg1031<kill>, 14, %reg0, %D0<imp-use,kill> When reg1031 and S0 are coalesced, the copy (FCPYS) will be eliminated the the implicit-kill of D0 is lost. In this case it's possible to move the marker to the FLDS. But in many cases, this is not possible. Suppose %reg1031<def> = FOO <cp#1>, %D0<imp-def> ... %S0<def> = FCPYS %reg1031<kill>, 14, %reg0, %D0<imp-use,kill> When FCPYS goes away, the definition of S0 is the "FOO" instruction. However, transferring the D0 implicit-kill to FOO doesn't work since it is the def of D0 itself. We need to fix this in another time by introducing a "kill" pseudo instruction to track liveness. Disabling the assertion is not ideal, but machine verifier is doing that job now. It's important to know double-def is not a miscomputation since it means a register should be free but it's not tracked as free. It's a performance issue instead. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82677 91177308-0d34-0410-b5e6-96231b3b80d8
* Simplify RegScavenger::FindUnusedReg.Jakob Stoklund Olesen2009-08-18
| | | | | | | | | - Drop the Candidates argument and fix all callers. Now that RegScavenger tracks available registers accurately, there is no need to restict the search. - Make sure that no aliases of the found register are in use. This was a potential bug. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79369 91177308-0d34-0410-b5e6-96231b3b80d8
* Replace RegScavenger::DistanceMap with a simpler local algorithm.Jakob Stoklund Olesen2009-08-16
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79195 91177308-0d34-0410-b5e6-96231b3b80d8
* Clean up the public interface of RegScavenger.Jakob Stoklund Olesen2009-08-16
| | | | | | Remove unused methods and make others private. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79194 91177308-0d34-0410-b5e6-96231b3b80d8
* Refine EarlyClobber assert in register scavenger.Jakob Stoklund Olesen2009-08-15
| | | | | | | | | | | | | | It is legal for an inline asm operand to use an earlyclobber register if the use operand is tied to the earlyclobber operand. The issue is discussed here: http://gcc.gnu.org/ml/gcc/1999-04n/msg00431.html We should perhaps let only the machine code verifier worry about these finer details. EarlyClobber operands are not really interesting to the scavenger. This fixes PR4528 for the third time. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79122 91177308-0d34-0410-b5e6-96231b3b80d8
* Track pristine registers as if they were live-in in the register scavenger.Jakob Stoklund Olesen2009-08-13
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78913 91177308-0d34-0410-b5e6-96231b3b80d8
* Rebuild RegScavenger::DistanceMap each time it is needed.Jakob Stoklund Olesen2009-08-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The register scavenger maintains a DistanceMap that maps MI pointers to their distance from the top of the current MBB. The DistanceMap is built incrementally in forward() and in bulk in findFirstUse(). It is used by scavengeRegister() to determine which candidate register has the longest unused interval. Unfortunately the DistanceMap contents can become outdated. The first time scavengeRegister() is called, the DistanceMap is filled to cover the MBB. If then instructions are inserted in the MBB (as they always are following scavengeRegister()), the recorded distances are too short. This causes bad behaviour in the included test case where a register use /after/ the current position is ignored because findFirstUse() thinks is is /before/ the current position. A "using an undefined register" assertion follows promptly. The fix is to build a fresh DistanceMap at the top of scavengeRegister(), and discard it after use. This means that DistanceMap is no longer needed as a RegScavenger member variable, and forward() doesn't need to update it. The fix then discloses issue number two in the same test case: The candidate search in scavengeRegister() finds a CSR that has been saved in the prologue, but is currently unused. It would be both inefficient and wrong to spill such a register in the emergency spill slot. In the present case, the emergency slot restore is placed immediately before the normal epilogue restore, leading to a "Redefining a live register" assertion. Fix number two: When scavengerRegister() stumbles upon an unused register that is overwritten later in the MBB, return that register early. It is important to verify that the register is defined later in the MBB, otherwise it might be an unspilled CSR. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78650 91177308-0d34-0410-b5e6-96231b3b80d8
* Remove RegisterScavenger::isSuperRegUsed(). This completely reverses the ↵Jakob Stoklund Olesen2009-08-08
| | | | | | | | | | | | | | | | mistaken commit r77904. Now there is no special treatment of instructions that redefine part of a super-register. Instead, the super-register is marked with <imp-use,kill> and <imp-def>. For instance, from LowerSubregs on ARM: subreg: CONVERTING: %Q1<def> = INSERT_SUBREG %Q1<undef>, %D1<kill>, 5 subreg: %D2<def> = FCPYD %D1<kill>, 14, %reg0, %Q1<imp-def> subreg: CONVERTING: %Q1<def> = INSERT_SUBREG %Q1, %D0<kill>, 6 subreg: %D3<def> = FCPYD %D0<kill>, 14, %reg0, %Q1<imp-use,kill>, %Q1<imp-def> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78466 91177308-0d34-0410-b5e6-96231b3b80d8
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