Commit Graph

4403 Commits

Author SHA1 Message Date
Owen Anderson 04cf3fd761 What the loop unroller cares about, rather than just not unrolling loops with calls, is
not unrolling loops that contain calls that would be better off getting inlined.  This mostly
comes up when an interleaved devirtualization pass has devirtualized a call which the inliner
will inline on a future pass.  Thus, rather than blocking all loops containing calls, add
a metric for "inline candidate calls" and block loops containing those instead.

llvm-svn: 113535
2010-09-09 20:32:23 +00:00
Owen Anderson 6270515918 Revert r113439, which relaxed the requirement that loops containing calls cannot be unrolled. After some discussion,
there seems to be a better way to achieve the same effect.

llvm-svn: 113528
2010-09-09 20:02:23 +00:00
Owen Anderson 11ab204fdc r113526 introduced an unintended change to the loop unrolling threshold. Revert it.
llvm-svn: 113527
2010-09-09 19:11:57 +00:00
Owen Anderson b61b1647e2 Fix typo in code to cap the loop code size reduction calculation.
llvm-svn: 113526
2010-09-09 19:08:59 +00:00
Owen Anderson 62ea1b718c Use code-size reduction metrics to estimate the amount of savings we'll get when we unroll a loop.
Next step is to recalculate the threshold values given this new heuristic.

llvm-svn: 113525
2010-09-09 19:07:31 +00:00
Owen Anderson 8084dbaf8e Relax the "don't unroll loops containing calls" rule. Instead, when a loop contains a call, lower the
unrolling threshold to the optimize-for-size threshold.  Basically, for loops containing calls, unrolling
can still be profitable as long as the loop is REALLY small.

llvm-svn: 113439
2010-09-08 23:10:07 +00:00
Owen Anderson a4d9c78aa1 Add a separate unrolling threshold when the current function is being optimized for size.
The threshold value of 50 is arbitrary, and I chose it simply by analogy to the inlining thresholds, where
the baseline unrolling threshold is slightly smaller than the baseline inlining threshold.  This could
undoubtedly use some tuning.

llvm-svn: 113306
2010-09-07 23:15:30 +00:00
Chris Lattner be9019090e fix PR8067, an over-aggressive assertion in LICM.
llvm-svn: 113146
2010-09-06 05:11:24 +00:00
Chris Lattner b01c24a945 Teach loop rotate to hoist trivially invariant instructions
in the duplicated block instead of duplicating them.  

Duplicating them into the end of the loop and the preheader 
means that we got a phi node in the header of the loop, 
which prevented LICM from hoisting them.  GVN would
usually come around later and merge the duplicated 
instructions so we'd get reasonable output... except that
anything dependent on the shoulda-been-hoisted value can't
be hoisted.  In PR5319 (which this fixes), a memory value
didn't get promoted.

llvm-svn: 113134
2010-09-06 01:10:22 +00:00
Chris Lattner da24b9a49a pull a simple method out of LICM into a new
Loop::hasLoopInvariantOperands method. Remove
a useless and confusing Loop::isLoopInvariant(Instruction)
method, which didn't do what you thought it did.

No functionality change.

llvm-svn: 113133
2010-09-06 01:05:37 +00:00
Chris Lattner 1edf7434cf more cleanups
llvm-svn: 113115
2010-09-05 20:13:07 +00:00
Chris Lattner e6214557e7 Change lower atomic pass to use IntrinsicInst to simplify it a bit.
llvm-svn: 113114
2010-09-05 20:10:47 +00:00
Chris Lattner 05ef361b5e eliminate some non-obvious casts. UndefValue isa Constant.
llvm-svn: 113113
2010-09-05 20:03:09 +00:00
Chris Lattner 65b48b5dfc zap dead code.
llvm-svn: 113073
2010-09-04 18:12:00 +00:00
Chris Lattner 50506787d1 fix a bug in my licm rewrite when a load from the promoted memory
location is being re-stored to the memory location.  We would get
a dangling pointer from the SSAUpdate data structure and miss a 
use.  This fixes PR8068

llvm-svn: 113042
2010-09-04 00:12:30 +00:00
Owen Anderson c91c1a205a Propagate non-local comparisons. Fixes PR1757.
llvm-svn: 113025
2010-09-03 22:47:08 +00:00
Owen Anderson c725462245 Add support for simplifying a load from a computed value to a load from a global when it
is provable that they're equivalent.  This fixes PR4855.

llvm-svn: 112994
2010-09-03 19:08:37 +00:00
Chris Lattner affc0e42f0 fix more AST updating bugs, correcting miscompilation in PR8041
llvm-svn: 112878
2010-09-02 22:19:10 +00:00
Duncan Sands 6778149f7e Reapply commit 112699, speculatively reverted by echristo, since
I'm sure it is harmless.  Original commit message:
If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory.  Instead, simply pass
in the type and name explicitly, which is all that was used anyway.

llvm-svn: 112810
2010-09-02 08:14:03 +00:00
Chris Lattner 8af45a889d deepen my MMX/SRoA hack to avoid hurting non-x86 codegen.
llvm-svn: 112763
2010-09-01 23:09:27 +00:00
Dan Gohman 0ad7d9c24e Fix loop unswitching's assumption that a code path which either
infinite loops or exits will eventually exit. This fixes PR5373.

llvm-svn: 112745
2010-09-01 21:46:45 +00:00
Owen Anderson 73f988cafa JumpThreading keeps LazyValueInfo up to date, so we don't need to rerun it
if we schedule another LVI-using pass afterwards.

llvm-svn: 112722
2010-09-01 18:27:22 +00:00
Eric Christopher a5d315c665 Speculatively revert 112699 and 112702, they seem to be causing
self host errors on clang-x86-64.

llvm-svn: 112719
2010-09-01 17:29:10 +00:00
Duncan Sands f7b18437b5 If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory.  Instead, simply pass
in the type and name explicitly, which is all that was used anyway.

llvm-svn: 112699
2010-09-01 10:29:33 +00:00
Chris Lattner 34e5361eb5 add a gross hack to work around a problem that Argiris reported
on llvmdev: SRoA is introducing MMX datatypes like <1 x i64>,
which then cause random problems because the X86 backend is
producing mmx stuff without inserting proper emms calls.

In the short term, force off MMX datatypes.  In the long term,
the X86 backend should not select generic vector types to MMX
registers.  This is being worked on, but won't be done in time
for 2.8.  rdar://8380055

llvm-svn: 112696
2010-09-01 05:14:33 +00:00
Dan Gohman 110ed64fbb Revert 112442 and 112440 until the compile time problems introduced
by 112440 are resolved.

llvm-svn: 112692
2010-09-01 01:45:53 +00:00
Chris Lattner 030f02021b licm is wasting time hoisting constant foldable operations,
instead of hoisting them, just fold them away.  This occurs in the
testcase for PR8041, for example.

llvm-svn: 112669
2010-08-31 23:00:16 +00:00
Chris Lattner daca6f3483 tidy up
llvm-svn: 112643
2010-08-31 21:21:25 +00:00
Owen Anderson 3c84ecb067 More cleanups of my JumpThreading transforms, including extracting some duplicated code into a helper function.
llvm-svn: 112634
2010-08-31 20:26:04 +00:00
Owen Anderson 6fdcb172a9 Add an RAII helper to make cleanup of the RecursionSet more fool-proof.
llvm-svn: 112628
2010-08-31 19:24:27 +00:00
Owen Anderson 048efbe225 Only try to clean up the current block if we changed that block already.
llvm-svn: 112625
2010-08-31 18:55:52 +00:00
Owen Anderson cd4de7f399 Refactor my fix for PR5652 to terminate the predecessor lookups after the first failure.
llvm-svn: 112620
2010-08-31 18:48:48 +00:00
Owen Anderson ce401be792 Don't perform an extra traversal of the function just to do cleanup. We can safely simplify instructions after each block has been processed without worrying about iterator invalidation.
llvm-svn: 112594
2010-08-31 07:55:56 +00:00
Owen Anderson 48d58ad64c Rename ValuePropagation to a more descriptive CorrelatedValuePropagation.
llvm-svn: 112591
2010-08-31 07:48:34 +00:00
Owen Anderson d2918a07bd Rename file to something more descriptive.
llvm-svn: 112590
2010-08-31 07:41:39 +00:00
Owen Anderson 3997a07fb9 More Chris-inspired JumpThreading fixes: use ConstantExpr to correctly constant-fold undef, and be more careful with its return value.
This actually exposed an infinite recursion bug in ComputeValueKnownInPredecessors which theoretically already existed (in JumpThreading's
handling of and/or of i1's), but never manifested before.  This patch adds a tracking set to prevent this case.

llvm-svn: 112589
2010-08-31 07:36:34 +00:00
Owen Anderson b58b3c0dda Fix a typo.
llvm-svn: 112560
2010-08-30 23:59:30 +00:00
Owen Anderson b974dbbdd7 Cleanups suggested by Chris.
llvm-svn: 112553
2010-08-30 23:34:17 +00:00
Owen Anderson c910acb54a Re-apply r112539, being more careful to respect the return values of the constant folding methods. Additionally,
use the ConstantExpr::get*() methods to simplify some constant folding.

llvm-svn: 112550
2010-08-30 23:22:36 +00:00
Owen Anderson 30bacbdfdf Add statistics to evaluate this pass.
llvm-svn: 112545
2010-08-30 22:45:55 +00:00
Owen Anderson 1ddcbbe49c Revert r112539. It accidentally introduced a miscompilation.
llvm-svn: 112543
2010-08-30 22:33:41 +00:00
Owen Anderson 75f6037c7c Fixes and cleanups pointed out by Chris. In general, be careful to handle 0 results from ComputeValueKnownInPredecessors
(indicating undef), and re-use existing constant folding APIs.

llvm-svn: 112539
2010-08-30 22:07:52 +00:00
Chris Lattner c843fca2fd rewrite DwarfEHPrepare to use SSAUpdater to promote its allocas
instead of PromoteMemToReg.  This allows it to stop using DF and DT,
eliminating a computation of DT and DF from clang -O3.  Clang is now
down to 2 runs of DomFrontier.

llvm-svn: 112457
2010-08-29 19:54:28 +00:00
Chris Lattner f58382ed87 two changes: 1) make AliasSet hold the list of call sites with an
assertingvh so we get a violent explosion if the pointer dangles.

2) Fix AliasSetTracker::deleteValue to remove call sites with
   by-pointer comparisons instead of by-alias queries.  Using
   findAliasSetForCallSite can cause alias sets to get merged
   when they shouldn't, and can also miss alias sets when the
   call is readonly.

#2 fixes PR6889, which only repros with a .c file :(

llvm-svn: 112452
2010-08-29 18:42:23 +00:00
Chris Lattner 263f804699 LICM does get dead instructions input to it. Instead of sinking them
out of loops, just delete them.

llvm-svn: 112451
2010-08-29 18:22:25 +00:00
Chris Lattner 6ac0659a1c use moveBefore instead of remove+insert, it avoids some
symtab manipulation, so its faster (in addition to being
more elegant)

llvm-svn: 112450
2010-08-29 18:18:40 +00:00
Chris Lattner f03b4eac48 revert 112448 for now.
llvm-svn: 112449
2010-08-29 18:11:16 +00:00
Chris Lattner 11f8ad8211 optimize LICM::hoist to use moveBefore. Correct its updating
of AST to remove the hoisted instruction from the AST, since it
is no longer in the loop.

llvm-svn: 112448
2010-08-29 18:03:33 +00:00
Chris Lattner 1a1ed69435 fix some bugs (found by inspection) where LICM would not update
LICM correctly.  When sinking an instruction, it should not add
entries for the sunk instruction to the AST, it should remove
the entry for the sunk instruction.  The blocks being sunk to
are not in the loop, so their instructions shouldn't be in the
AST (yet)!

llvm-svn: 112447
2010-08-29 18:00:00 +00:00
Chris Lattner cc9cbc66a3 rework the ownership of subloop alias information: instead of
keeping them around until the pass is destroyed, keep them
around a) just when useful (not for outer loops) and b) destroy
them right after we use them.  This should reduce memory use
and fixes potential bugs where a loop is deleted and another
loop gets allocated to the same address.

llvm-svn: 112446
2010-08-29 17:46:00 +00:00