Commit Graph

129 Commits

Author SHA1 Message Date
Bob Wilson
cc80df92c1 Overhaul the TwoAddressInstructionPass to simplify the logic, especially
for the complicated case where one register is tied to multiple destinations.
This avoids the extra scan of instruction operands that was introduced by
my recent change.  I also pulled some code out into a separate
TryInstructionTransform method, added more comments, and renamed some
variables.

Besides all those changes, this takes care of a FIXME in the code regarding
an assumption about there being a single tied use of a register when
converting to a 3-address form.  I'm not aware of cases where that assumption
is violated, but the code now only attempts to transform an instruction,
either by commuting its operands or by converting to a 3-address form,
for the simple case where there is a single pair of tied operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80945 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-03 20:58:42 +00:00
Bob Wilson
d163917fd8 Rearrange code to eliminate redundancy and avoid gotos.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80798 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-02 16:35:35 +00:00
Bob Wilson
86f7cd786e Avoid calling removeVirtualRegisterKilled which iterates over the operands
to find the kill, since we already have the operand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80736 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-01 23:18:46 +00:00
Bob Wilson
326f43812c Refactor some code into separate functions. No functional changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80733 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-01 22:51:08 +00:00
Bob Wilson
c08f5fe882 Move use of LV inside condition that guards for null LV.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80731 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-01 22:19:00 +00:00
Bob Wilson
71124f698b Fix pr4843: When an instruction has multiple destination registers that are
tied to different source registers, the TwoAddressInstructionPass needs to
be smarter.  Change it to check before replacing a source register whether
that source register is tied to a different destination register, and if so,
defer handling it until a subsequent iteration.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80654 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-01 04:18:40 +00:00
Bob Wilson
4344979ba9 Use early exit and reduce indentation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80631 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-31 21:54:55 +00:00
Bob Wilson
d4034b2825 If the tied registers are already the same, there is no need to change
them.  Move the code to make that change inside the conditional.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80630 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-31 21:54:16 +00:00
Chris Lattner
6456d3868d remove some DOUTs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79812 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-23 03:20:44 +00:00
Evan Cheng
3a3cce59c4 Code clean up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78360 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-07 00:28:58 +00:00
Dan Gohman
845012e6d3 Use setPreservesAll and setPreservesCFG in CodeGen passes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77754 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-31 23:37:33 +00:00
Daniel Dunbar
ce63ffb52f More migration to raw_ostream, the water has dried up around the iostream hole.
- Some clients which used DOUT have moved to DEBUG. We are deprecating the
   "magic" DOUT behavior which avoided calling printing functions when the
   statement was disabled. In addition to being unnecessary magic, it had the
   downside of leaving code in -Asserts builds, and of hiding potentially
   unnecessary computations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77019 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-25 00:23:56 +00:00
Evan Cheng
33d0474bf5 Use TII->findCommutedOpIndices to find the commute operands (rather than guessing).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76472 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-20 21:16:08 +00:00
Evan Cheng
378445303b Let callers decide the sub-register index on the def operand of rematerialized instructions.
Avoid remat'ing instructions whose def have sub-register indices for now. It's just really really hard to get all the cases right.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75900 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-16 09:20:10 +00:00
Evan Cheng
ebfc177b59 Two-address pass should use findCommutedOpIndices to determine what registers are commuted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75317 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-11 00:04:23 +00:00
Evan Cheng
aed4a430f4 Eliminate VarInfo::UsedBlocks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72411 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-26 06:25:46 +00:00
Lang Hames
a7c9deaa2b Fix for PR4124. Make TwoAddressFormPass::FindLastUseInMBB return the real last use.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71769 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-14 04:26:30 +00:00
Lang Hames
60dc7345eb Fix for PR4121. If TwoAddressInstructionPass removes a dead def, and the regB
operand was killed, the kill needs to be removed from regB's VarInfo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71635 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-13 04:18:47 +00:00
Mike Stump
1e8f072f19 Avoid warning in release-asserts build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71275 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-08 22:53:06 +00:00
Evan Cheng
e9ccb3a7d4 Fix for PR4051. When 2address pass delete an instruction, update kill info when necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70279 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-28 02:12:36 +00:00
Evan Cheng
87d696a4d2 Fix PR3934 part 2. findOnlyInterestingUse() was not setting IsCopy and IsDstPhys which are returned by value and used by callee. This happened to work on the earlier test cases because of a logic error in the caller side.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69006 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-14 00:32:25 +00:00
Evan Cheng
3005ed6048 PR3934: Fix a bogus two-address pass assertion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68979 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-13 20:04:24 +00:00
Dan Gohman
6ed0e20eb2 Add an assertion to verify that a copy was actually emitted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68953 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-13 15:16:56 +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
Evan Cheng
e6f350d755 Turn a 2-address instruction into a 3-address one when it's profitable even if the two-address operand is killed.
e.g.
%reg1024<def> = MOV r1
%reg1025<def> = ADD %reg1024, %reg1026
r0            = MOV %reg1025

If it's not possible / profitable to commute ADD, then turning ADD into a LEA saves a copy.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68065 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-30 21:34:07 +00:00
Evan Cheng
fb11288109 Model inline asm constraint which ties an input to an output register as machine operand TIED_TO constraint. This eliminated the need to pre-allocate registers for these. This also allows register allocator can eliminate the unneeded copies.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67512 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-23 08:01:15 +00:00
Evan Cheng
a24752ff43 Added MachineInstr::isRegTiedToDefOperand to check for two-addressness.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67335 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-19 20:30:06 +00:00
Evan Cheng
870b80722f Minor optimization:
Look for situations like this:                                                                                                                                                              
%reg1024<def> = MOV r1                                                                                                                                                                      
%reg1025<def> = MOV r0                                                                                                                                                                      
%reg1026<def> = ADD %reg1024, %reg1025                                                                                                                                                      
r0            = MOV %reg1026                                                                                                                                                                
Commute the ADD to hopefully eliminate an otherwise unavoidable copy.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65752 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-01 02:03:43 +00:00
Evan Cheng
28c7ce3fd4 If two-address def is dead and the instruction does not define other registers, and it doesn't produce side effects, just delete the instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65218 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-21 03:14:25 +00:00
Duncan Sands
1465d61bdd Rename getAnalysisToUpdate to getAnalysisIfAvailable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63198 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-28 13:14:17 +00:00
Evan Cheng
d498c8f2c8 Teach 2addr pass to be do more commuting. If both uses of a two-address instruction are killed, but the first operand has a use before and after the def, commute if the second operand does not suffer from the same issue.
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1028                                                                                                                                            
%reg1030<def> = ADD8rr %reg1028<kill>, %reg1029<kill>, %EFLAGS<imp-def,dead>                                                                                                         

In this case, it might not be possible to coalesce the second MOV8rr                                                                                                                 
instruction if the first one is coalesced. So it would be profitable to                                                                                                              
commute it:                                                                                                                                                                          
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1029                                                                                                                                            
%reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62954 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-25 03:53:59 +00:00
Evan Cheng
8191371f87 Refactor code. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62893 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-23 23:27:33 +00:00
Dan Gohman
d68a07650c Tidy up #includes, deleting a bunch of unnecessary #includes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61715 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-05 17:59:02 +00:00
Dan Gohman
2d9716f7bf Do the LiveVariables update before printing the instruction in
the debug output, so that the updated liveness flags are
reflected in the debug output.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59147 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-12 17:15:19 +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
Dan Gohman
ae73dc1448 Tidy up several unbeseeming casts from pointer to intptr_t.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55779 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-04 17:05:41 +00:00
Evan Cheng
8763c1c544 Move the check whether it's worth remating to caller.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55434 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-27 20:58:54 +00:00
Evan Cheng
df3b99381f Refactor isSafeToReMat out of 2addr pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55430 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-27 20:33:50 +00:00
Evan Cheng
9f1c8317a4 - Remove calls to copyKillDeadInfo which is an N^2 function. Instead, propagate kill / dead markers as new instructions are constructed in foldMemoryOperand, convertToThressAddress, etc.
- Also remove LiveVariables::instructionChanged, etc. Replace all calls with cheaper calls which update VarInfo kill list.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53097 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-03 09:09:37 +00:00
Evan Cheng
be04dc1413 - Add LiveVariables::replaceKillInstruction. This does a subset of instructionChanged. That is, it only update the VarInfo.kills if the new instruction is known to have the correct dead and kill markers.
- CommuteInstruction copies kill / dead markers over to new instruction. So use replaceKillInstruction instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53061 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-03 00:07:19 +00:00
Owen Anderson
f660c171c8 Make LiveVariables even more optional, by making it optional in the call to TargetInstrInfo::convertToThreeAddressInstruction
Also, if LV isn't around, then TwoAddr doesn't need to be updating flags, since they won't have been set in the first place.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53058 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-02 23:41:07 +00:00
Owen Anderson
802af11460 TwoAddressInstructionPass doesn't really require LiveVariables, it just needs to update it if it's already around.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53049 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-02 21:28:58 +00:00
Evan Cheng
fdb99838a3 Remove unneeded include.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52920 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-30 20:38:22 +00:00
Evan Cheng
601ca4b434 Enable two-address remat by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52701 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-25 01:16:38 +00:00
Evan Cheng
32a3ac7911 Missed a check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52487 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-19 06:17:19 +00:00
Evan Cheng
7543e58a77 Complete support for two-address pass rematerialization. Now *almost* always a win.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52452 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-18 07:49:14 +00:00
Bill Wendling
bd0879d7d9 Implement "AsCheapAsAMove" for some obviously cheap instructions: xor and the
like.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51662 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-29 01:02:09 +00:00
Bill Wendling
a8db14796b Check the "isSafeToMove" predicate, which has a series of tests to make sure
that it's safe to remat an instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51659 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-28 22:52:47 +00:00
Bill Wendling
b0f65e1348 Incorporated feedback: Check that the implicitly defined operands aren't used
before deleting the instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51609 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-27 20:40:52 +00:00