Commit Graph

170 Commits

Author SHA1 Message Date
Lang Hames
9c992f1141 Fixed PR4090.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71495 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-11 23:14:13 +00:00
Jakob Stoklund Olesen
3a155f0e34 Join cross class copies using getCommonSubClass()
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70513 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-30 21:24:03 +00:00
Evan Cheng
0490dcb1b7 Add a smarter heuristic to determine when to coalesce a virtual register with a physical one. More specifically, it avoid tying a virtual register in the loop with a physical register defined / used outside the loop. When it determines it's not profitable, it will use the physical register as the allocation preference instead.
This is *not* turned on by default. Testing indicates this is just as likely to pessimize code. The main issue seems to be allocation preference doesn't work effectively. That will change once I've taught register allocator "swapping".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70503 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-30 18:39:57 +00:00
Evan Cheng
8a8a0dfc3b Move getMatchingSuperReg() out of coalescer and into TargetRegisterInfo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70309 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-28 18:29:27 +00:00
Jakob Stoklund Olesen
08e791fdb3 Don't coalesce a physical register with an incompatible virtual register.
If the physical register does not belong to the virtual register's regclass,
don't coalesce. The physical register could be an invalid operand for an
instruction using the vreg.

The regclass matching is done after determining the actual subregisters being copied.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70298 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-28 16:34:35 +00:00
Owen Anderson
82fd3f3d3a Don't skip the CopyMI when removing kill markers.
This should have no effect on generated code, but makes the intermediate state
of the coalescer more sane.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70238 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-27 19:55:47 +00:00
Evan Cheng
aa809fbde1 Update comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69919 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-23 20:39:31 +00:00
Evan Cheng
c2cee14a8c Fix an obvious type.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69918 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-23 20:18:13 +00:00
Dan Gohman
97121ba2af Implement support for using modeling implicit-zero-extension on x86-64
with SUBREG_TO_REG, teach SimpleRegisterCoalescing to coalesce
SUBREG_TO_REG instructions (which are similar to INSERT_SUBREG
instructions), and teach the DAGCombiner to take advantage of this on
targets which support it. This eliminates many redundant
zero-extension operations on x86-64.

This adds a new TargetLowering hook, isZExtFree. It's similar to
isTruncateFree, except it only applies to actual definitions, and not
no-op truncates which may not zero the high bits.

Also, this adds a new optimization to SimplifyDemandedBits: transform
operations like x+y into (zext (add (trunc x), (trunc y))) on targets
where all the casts are no-ops. In contexts where the high part of the
add is explicitly masked off, this allows the mask operation to be
eliminated. Fix the DAGCombiner to avoid undoing these transformations
to eliminate casts on targets where the casts are no-ops.

Also, this adds a new two-address lowering heuristic. Since
two-address lowering runs before coalescing, it helps to be able to
look through copies when deciding whether commuting and/or
three-address conversion are profitable.

Also, fix a bug in LiveInterval::MergeInClobberRanges. It didn't handle
the case that a clobber range extended both before and beyond an
existing live range. In that case, multiple live ranges need to be
added. This was exposed by the new subreg coalescing code.

Remove 2008-05-06-SpillerBug.ll. It was bugpoint-reduced, and the
spiller behavior it was looking for no longer occurrs with the new
instruction selection.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68576 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-08 00:15:30 +00:00
Bill Wendling
430d423e4b Fix grammar-o in comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68057 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-30 20:30:02 +00:00
Evan Cheng
a597a97618 My last coalescer fix introduced a subtler one. It's aborting a commuting optimization too late and left the live intervals to be out of sync with instructions. This fixes 8b10b.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66715 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-11 22:18:44 +00:00
Evan Cheng
a2e6435e48 Two coalescer fixes in one.
1. Use the same value# to represent unknown values being merged into sub-registers.
2. When coalescer commute an instruction and the destination is a physical register, update its sub-registers by merging in the extended ranges.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66610 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-11 00:03:21 +00:00
Evan Cheng
58207f12ee If a use operand is marked isKill, don't forget to add kill to its live interval as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65279 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-22 08:35:56 +00:00
Evan Cheng
190424edcd Fix another case ShortenDeadCopySrcLiveRange is shortening too much. No test case possible since I don't know what to grep for. :-(
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64125 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-09 08:37:45 +00:00
Evan Cheng
0a1fcce092 Fix PR3486. Fix a bug in code that manually patch physical register live interval after its sub-register is coalesced with a virtual register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64082 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-08 11:04:35 +00:00
Evan Cheng
86fb9fdb20 Strengthen the previous check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64076 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-08 08:24:28 +00:00
Evan Cheng
f18134a1ae r64073 commit message is lost. Here it is:
Right now if the coalesced copy def is dead and its src is a kill, and that
there are now other uses within the live range, the coalescer would mark the
def of the source register as dead. But it should also check if there are
other kills which means the value has other uses not in the live range.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64075 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-08 08:00:36 +00:00
Evan Cheng
77fde2cbb1 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64073 91177308-0d34-0410-b5e6-96231b3b80d8 2009-02-08 07:48:37 +00:00
Evan Cheng
54801f78b1 isAsCheapAsMove instructions can have register src operands. Check if they are really re-materializable.
This fixes sse.expandfft and sse.stepfft.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63890 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-05 22:24:17 +00:00
Evan Cheng
961154f2db ReMaterializeTrivialDef need to trim the live interval to the last kill if the copy kills the source register. This fixes uint64tof64.ll after ARM::MOVi is marked as isAsCheapAsAMove.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63853 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-05 08:45:04 +00:00
Evan Cheng
6792e90fec Skip over zero registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63748 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-04 18:18:58 +00:00
Evan Cheng
c16d37ead0 Only check if coalescing is worthwhile when the result is targeting a more restrictive register class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62837 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-23 05:48:59 +00:00
Evan Cheng
8c08d8c77c Cross register class coalescing. Not yet enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62832 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-23 02:15:19 +00:00
Evan Cheng
04ee5a1d92 Change TargetInstrInfo::isMoveInstr to return source and destination sub-register indices as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62600 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-20 19:12:24 +00:00
Evan Cheng
e08eb9ca1d Refactor code. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62573 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-20 06:44:16 +00:00
Dan Gohman
fd246e5f84 Use assertions to check for conditions that should never happen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62178 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-13 20:25:24 +00:00
Evan Cheng
167650d411 Un-tabify.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62151 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-13 06:08:37 +00:00
Evan Cheng
1d8a76d7d5 FIX llvm-gcc bootstrap on x86_64 linux. If a virtual register is copied to a physical register, it's not necessarily defined by a copy. We have to watch out it doesn't clobber any sub-register that might be live during its live interval. If the live interval crosses a basic block, then it's not safe to check with the less conservative check (by scanning uses and defs) because it's possible a sub-register might be live out of the block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62144 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-13 03:57:45 +00:00
Evan Cheng
8f90b6eb2f The coalescer does not coalesce a virtual register to a physical register if any of the physical register's sub-register live intervals overlaps with the virtual register. This is overly conservative. It prevents a extract_subreg from being coalesced away:
v1024 = EDI  // not killed
      =
      = EDI

One possible solution is for the coalescer to examine the sub-register live intervals in the same manner as the physical register. Another possibility is to examine defs and uses (when needed) of sub-registers. Both solutions are too expensive. For now, look for "short virtual intervals" and scan instructions to look for conflict instead.

This is a small win on x86-64. e.g. It shaves 403.gcc by ~80 instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61847 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-07 02:08:57 +00:00
Devang Patel
8a84e4402a squash warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61707 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-05 17:31:22 +00:00
Evan Cheng
5379f412bc Fix PR3149. If an early clobber def is a physical register and it is tied to an input operand, it effectively extends the live range of the physical register. Currently we do not have a good way to represent this.
172     %ECX<def> = MOV32rr %reg1039<kill>
180     INLINEASM <es:subl $5,$1
        sbbl $3,$0>, 10, %EAX<def>, 14, %ECX<earlyclobber,def>, 9, %EAX<kill>,
36, <fi#0>, 1, %reg0, 0, 9, %ECX<kill>, 36, <fi#1>, 1, %reg0, 0
188     %EAX<def> = MOV32rr %EAX<kill>
196     %ECX<def> = MOV32rr %ECX<kill>
204     %ECX<def> = MOV32rr %ECX<kill>
212     %EAX<def> = MOV32rr %EAX<kill>
220     %EAX<def> = MOV32rr %EAX
228     %reg1039<def> = MOV32rr %ECX<kill>

The early clobber operand ties ECX input to the ECX def.

The live interval of ECX is represented as this:
%reg20,inf = [46,47:1)[174,230:0)  0@174-(230) 1@46-(47)

The right way to represent this is something like
%reg20,inf = [46,47:2)[174,182:1)[181:230:0)  0@174-(182) 1@181-230 @2@46-(47)

Of course that won't work since that means overlapping live ranges defined by two val#.

The workaround for now is to add a bit to val# which says the val# is redefined by a early clobber def somewhere. This prevents the move at 228 from being optimized away by SimpleRegisterCoalescing::AdjustCopiesBackFrom.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61259 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-19 20:58:01 +00:00
Bill Wendling
bebbded574 Perform this loop only when the -debug flag is specified.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61238 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-19 02:09:57 +00:00
Evan Cheng
b3990d5e94 Remove val# defined by a remat'ed def that is now dead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58294 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-27 23:21:01 +00:00
Dan Gohman
3afda6e9d1 When the coalescer is doing rematerializing, have it remove
the copy instruction from the instruction list before asking the
target to create the new instruction. This gets the old instruction
out of the way so that it doesn't interfere with the target's
rematerialization code. In the case of x86, this helps it find
more cases where EFLAGS is not live.

Also, in the X86InstrInfo.cpp, teach isSafeToClobberEFLAGS to check
to see if it reached the end of the block after scanning each
instruction, instead of just before. This lets it notice when the
end of the block is only two instructions away, without doing any
additional scanning.

These changes allow rematerialization to clobber EFLAGS in more
cases, for example using xor instead of mov to set the return value
to zero in the included testcase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57872 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-21 03:24:31 +00:00
Evan Cheng
195cd3a58d Also update sub-register intervals after a trivial computation is rematt'ed for a copy instruction. PR2775.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57458 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-13 18:35:52 +00:00
Chris Lattner
99cbdff66c fix typo
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57388 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-11 23:59:03 +00:00
Owen Anderson
95dad830bb Add an option to enable StrongPHIElimination, for ease of testing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57259 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-07 20:22:28 +00:00
Dan Gohman
d735b8019b Switch the MachineOperand accessors back to the short names like
isReg, etc., from isRegister, etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57006 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-03 15:45:36 +00:00
Evan Cheng
dc37786595 Re-apply 56835 along with header file changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56848 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-30 15:44:16 +00:00
Duncan Sands
46292be362 Revert commit 56835 since it breaks the build.
"If a re-materializable instruction has a register
operand, the spiller will change the register operand's
spill weight to HUGE_VAL to avoid it being spilled.
However, if the operand is already in the queue ready
to be spilled, avoid re-materializing it".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56837 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-30 10:00:30 +00:00
Evan Cheng
d41474d2c0 If a re-materializable instruction has a register operand, the spiller will change the register operand's spill weight to HUGE_VAL to avoid it being spilled. However, if the operand is already in the queue ready to be spilled, avoid re-materializing it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56835 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-30 06:36:58 +00:00
Dale Johannesen
86b49f8e2d Next round of earlyclobber handling. Approach the
RA problem by expanding the live interval of an
earlyclobber def back one slot.  Remove
overlap-earlyclobber throughout.  Remove 
earlyclobber bits and their handling from
live internals.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56539 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-24 01:07:17 +00:00
Evan Cheng
bbeeb2a61e Mark several codegen passes as preserving all analysis.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56469 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-22 20:58:04 +00:00
Dale Johannesen
34d8f7559c Teach coalescer about earlyclobber bits.
Check bits for preferred register.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56384 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-20 02:03:04 +00:00
Evan Cheng
fee2d6937c Continue after removing the current MI.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56372 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-19 22:49:39 +00:00
Evan Cheng
20580a1cf6 Re-materalized definition instructions may be dead. Whack them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56352 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-19 17:38:47 +00:00
Evan Cheng
870e4bef41 Unallocatable registers do not have live intervals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56287 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-17 18:36:25 +00:00
Evan Cheng
25f34a30d6 Correctly update kill infos after extending a live range and merge 2 val#'s; fix 56165 - do not mark val# copy field if the copy does not define the val#.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56199 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-15 06:28:41 +00:00
Dan Gohman
014278e6a1 Remove isImm(), isReg(), and friends, in favor of
isImmediate(), isRegister(), and friends, to avoid confusion
about having two different names with the same meaning. I'm
not attached to the longer names, and would be ok with
changing to the shorter names if others prefer it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56189 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-13 17:58:21 +00:00
Evan Cheng
ee9e1b0a85 On some targets, non-move instructions can become move instructions because of coalescing. e.g.
vr2 = OR vr0, vr1
=>
vr2 = OR vr1, vr1   // after coalescing vr0 with vr1

Update the value# of the destination register with the copy instruction if that happens.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56165 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-12 18:13:14 +00:00