210fc62a91
In some rare cases, the register allocator can spill registers but end up not utilizing registers at all. The fundamental problem is linearscan's backtracking can end up freeing more than one allocated registers. However, reloads and restores might be folded into uses / defs and freed registers might not be used at all.
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VirtRegMap keeps track of allocations so it knows what's not used. As a horrible hack, the stack coloring can color spill slots with *free* registers. That is, it replace reload and spills with copies from and to the free register. It unfold instructions that load and store the spill slot and replace them with register using variants.
Not yet enabled. This is part 1. More coming.
llvm-svn: 70787
2009-05-03 18:32:42 +00:00
51856173c8
Fix pr3954. The register scavenger asserts for inline assembly with
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register destinations that are tied to source operands. The
TargetInstrDescr::findTiedToSrcOperand method silently fails for inline
assembly. The existing MachineInstr::isRegReDefinedByTwoAddr was very
close to doing what is needed, so this revision makes a few changes to
that method and also renames it to isRegTiedToUseOperand (for consistency
with the very similar isRegTiedToDefOperand and because it handles both
two-address instructions and inline assembly with tied registers).
llvm-svn: 68714
2009-04-09 17:16:43 +00:00
4486c1fac0
Remove the "fast" cases for spill and restore point determination, as these were subtlely wrong in obscure cases. Patch the testcase
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to account for this change.
llvm-svn: 68093
2009-03-31 08:27:09 +00:00
0422efc994
Give the pre-alloc splitter access to the VirtRegMap. It doesn't do anything
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useful with it at the moment, but it will in the future.
llvm-svn: 67012
2009-03-14 21:40:05 +00:00
380b3838f6
(Hopefully) silence a warning.
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llvm-svn: 66158
2009-03-05 08:23:20 +00:00
ad503987a8
Be more careful about choosing restore points when doing restore folding. This fixes some subtle miscompilations.
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llvm-svn: 66147
2009-03-05 07:19:18 +00:00
0dedc114de
Add a restore folder, which shaves a dozen or so machineinstrs off oggenc. Update a testcase to check this.
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llvm-svn: 66029
2009-03-04 08:52:31 +00:00
f13820148b
Fix a crash in the pre-alloc splitter exposed by recent codegen changes.
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llvm-svn: 65121
2009-02-20 10:02:23 +00:00
b5f0ec3eb7
Add TargetInstrInfo::isSafeToMoveRegisterClassDefs. It returns true if it's safe to move an instruction which defines a value in the register class. Replace pre-splitting specific IgnoreRegisterClassBarriers with this new hook.
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llvm-svn: 63936
2009-02-06 17:17:30 +00:00
7411523ee6
Pre-alloc splitting needs to be more careful to avoid inserting spills/restores
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between call frame setup/restore points. Unfortunately, this regresses
code size a bit, but at least it's correct now!
llvm-svn: 63837
2009-02-05 05:58:41 +00:00
4eda2cbe5f
MergeValueInto is too smart: it might choose to do the merge the opposite direction.
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Live interval reconstruction needs to account for this, and scour its maps to
prevent dangling references.
llvm-svn: 63558
2009-02-02 22:42:01 +00:00
03f862579c
Refactor PerformPHIConstruction, no functionality changes.
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llvm-svn: 63536
2009-02-02 18:33:18 +00:00
19616c08a0
Fix test failures causes by my previous commit.
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llvm-svn: 63492
2009-02-01 08:41:54 +00:00
66838e9a27
Fix an issue in PHI construction that was exposed by GCC 4.2 producing a different set iteration order for the reg_iterator.
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llvm-svn: 63490
2009-02-01 07:06:00 +00:00
bf77d2eb9d
Correct the algorithms for choosing spill and restore points so that we don't try to insert loads/stores between call frame setup and the actual call.
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This fixes the last known failure for the pre-alloc-splitter.
llvm-svn: 63339
2009-01-29 22:13:06 +00:00
c0924a0632
Fix an issue where restores could be inserted after a terminator instruction,
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and an iterator invalidation issue.
FreeBench/pifft no longer miscompiles with these fixes!
llvm-svn: 63293
2009-01-29 08:22:06 +00:00
a590802ed6
Comments are good. :-)
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llvm-svn: 63276
2009-01-29 05:41:02 +00:00
b05ce78c51
Add support for aggressive load-use-store folding. This takes care of the
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vast majority of code size regressions introduced by pre-alloc-splitting.
llvm-svn: 63274
2009-01-29 05:28:55 +00:00
431053ed2c
Make the pre-split-limit option more useful by using a per-function counter.
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llvm-svn: 63091
2009-01-27 05:01:15 +00:00
e84c3f261e
Reapply r63025 and r63026, with fixes for the failing testcases.
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llvm-svn: 63049
2009-01-26 21:57:31 +00:00
e7fa3c37c6
Also revert r63206
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llvm-svn: 63041
2009-01-26 21:30:17 +00:00
a39c83d118
Temporarily revert r63025 until the testsuite failures can be fixed.
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llvm-svn: 63040
2009-01-26 21:27:03 +00:00
5e235d3a7e
Get rid of a bunch of dead code now that interval reconstruction is enabled.
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llvm-svn: 63026
2009-01-26 19:18:06 +00:00
feffdec244
Fix an issue where LiveIntervals was trying to be smart about removing kill
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markers, and ended up foiling the interval reconstruction.
This allows us to turn on reconstruction in the pre alloc splitter, which
fixes a number of miscompilations.
llvm-svn: 63025
2009-01-26 19:12:06 +00:00
72287a599f
Silence a bogus compiler warning.
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llvm-svn: 63021
2009-01-26 18:33:51 +00:00
ee34b8f179
Some cleanups. No functional changes.
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llvm-svn: 62917
2009-01-24 10:07:43 +00:00
a2ca64a39a
Stage two of fixing pre-alloc-splitting's code size issues: filter out restores that are just
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going to be re-spilled again.
This also helps performance. Pre-alloc-splitting now seems to be an overall win on SPEC.
llvm-svn: 62834
2009-01-23 03:28:53 +00:00
48abf2380b
Add an initial pass at dead spill/restore removal for pre alloc splitting.
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llvm-svn: 62821
2009-01-23 00:23:32 +00:00
fe48dfa0f2
I accidentally removed this check in an earlier commit, which cause breakage in the pre alloc splitter.
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llvm-svn: 62678
2009-01-21 08:18:03 +00:00
be7a29de0b
Be more aggressive about renumbering vregs after splitting them.
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llvm-svn: 62639
2009-01-21 00:13:28 +00:00
c544cb0eca
Change TargetInstrInfo::isMoveInstr to return source and destination sub-register indices as well.
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llvm-svn: 62600
2009-01-20 19:12:24 +00:00
45cfef2cb6
More two-address fixes. This gets lua working with join-creation enabled.
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llvm-svn: 62073
2009-01-12 03:10:40 +00:00
f04100a50d
The phi construction algorithm used for interval reconstruction is complicated by
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two address instructions. We need to keep track of things we've processed AS USES
independetly of whether we've processed them as defs.
This fixes all known miscompilations when reconstruction is turned on.
llvm-svn: 61802
2009-01-06 07:53:32 +00:00
96fce00dc0
Get rid of sentinel insertion in interval reconstruction. It just masked the
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problem, rather than fixing it. The problem has now been fixed the right way.
llvm-svn: 61723
2009-01-05 18:32:26 +00:00
8b86b9ca47
Get live interval reconstruction several steps closer to working.
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llvm-svn: 61514
2008-12-31 02:00:25 +00:00
43b18241ff
Add braces, as suggested by a gcc warning.
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llvm-svn: 61465
2008-12-29 08:05:02 +00:00
b5232286a7
Fix up kill/dead marking in the new live interval reconstruction code.
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llvm-svn: 61460
2008-12-28 23:35:13 +00:00
37751bb9d9
Add prototype code for recomputing a live interval's ranges and valnos through recursive phi construction.
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llvm-svn: 61458
2008-12-28 21:48:48 +00:00
ad4d2ab15b
Re-apply r61158 in a form that no longer breaks tests.
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llvm-svn: 61182
2008-12-18 01:27:19 +00:00
59727c0496
Revert r61158 for now, as it caused some test failures.
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llvm-svn: 61159
2008-12-17 22:17:27 +00:00
9389176009
Fix miscompilations caused by renumbering, and enable it as part of prealloc splitting.
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llvm-svn: 61158
2008-12-17 22:06:59 +00:00
5121ec3821
Add code to renumber split intervals into new vregs. This is disabled for now until I finish working out some iterator invalidation issues.
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llvm-svn: 61104
2008-12-16 21:35:08 +00:00
12679470bf
Switch to top-down mode and fix a crasher this exposed caused by an error in the
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live interval updating.
llvm-svn: 60652
2008-12-07 05:33:18 +00:00
0bcbe8f6a8
Factor out some common code.
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llvm-svn: 60553
2008-12-04 21:20:30 +00:00
ecd5b5f2b2
Add support for folding spills into preceding defs when doing pre-alloc splitting.
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llvm-svn: 60433
2008-12-02 18:53:47 +00:00
1af37c2fca
Add support for rematerialization in pre-alloc-splitting.
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llvm-svn: 59587
2008-11-19 04:28:29 +00:00
896512af94
Fix a bug introduced by my previous patch. With this change, SPEC is now clean with prealloc splitting enabled.
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llvm-svn: 59544
2008-11-18 20:53:59 +00:00
d36b4c1bf8
Don't allow the restore point to be placed after terminators. With this change,
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MultiSource/Applications is clean with the prealloc splitter. Some failures
remain in SPEC.
llvm-svn: 59267
2008-11-13 21:53:14 +00:00
fd395eb801
Don't walk into predecessors in which the vreg is not live when doing shrinkwrapping.
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This lets several failing tests get farther along, but doesn't completely fix any of them.
llvm-svn: 59086
2008-11-11 22:11:27 +00:00
26c10f1b4a
Use the new predicate to control when we do prealloc splitting. Fix a small bug.
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llvm-svn: 58738
2008-11-05 00:32:13 +00:00
Evan Cheng