Commit Graph

168 Commits

Author SHA1 Message Date
Quentin Colombet
e644b7743b Fix a bug in IfConverter with nested predicates.
Prior to this patch, IfConverter may widen the cases where a sequence of
instructions were executed because of the way it uses nested predicates. This
result in incorrect execution.

For instance, Let A be a basic block that flows conditionally into B and B be a
predicated block.
B can be predicated with A.BrToBPredicate into A iff B.Predicate is less
"permissive" than A.BrToBPredicate, i.e., iff A.BrToBPredicate subsumes
B.Predicate.

The IfConverter was checking the opposite: B.Predicate subsumes
A.BrToBPredicate.

<rdar://problem/14379453>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187071 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-24 20:20:37 +00:00
Chad Rosier
62c320a755 Simplify logic now that r182490 is in place. No functional change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182531 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-22 23:17:36 +00:00
Evan Cheng
9a28cc14a9 Teach if-converter to avoid removing BBs whose addresses are takne. rdar://13782395
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181160 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-05 18:03:49 +00:00
Hal Finkel
9af7014019 Manually remove successors in if conversion when CopyAndPredicateBlock is used
In the simple and triangle if-conversion cases, when CopyAndPredicateBlock is
used because the to-be-predicated block has other predecessors, we need to
explicitly remove the old copied block from the successors list. Normally if
conversion relies on TII->AnalyzeBranch combined with BB->CorrectExtraCFGEdges
to cleanup the successors list, but if the predicated block contained an
un-analyzable branch (such as a now-predicated return), then this will fail.

These extra successors were causing a problem on PPC because it was causing
later passes (such as PPCEarlyReturm) to leave dead return-only basic blocks in
the code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179227 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-10 22:05:25 +00:00
Jakob Stoklund Olesen
dd4fc446b5 Avoid creating duplicate CFG edges in the IfConversion pass.
Patch by Stefan Hepp.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173395 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-24 23:59:08 +00:00
Benjamin Kramer
69e42dbd00 Split TargetLowering into a CodeGen and a SelectionDAG part.
This fixes some of the cycles between libCodeGen and libSelectionDAG. It's still
a complete mess but as long as the edges consist of virtual call it doesn't
cause breakage. BasicTTI did static calls and thus broke some build
configurations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172246 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-11 20:05:37 +00:00
Jakob Stoklund Olesen
7b79b9862c Use MachineInstrBuilder in a few CodeGen passes.
This automatically passes a context pointer to MI->addOperand().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170711 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 18:08:06 +00:00
Chandler Carruth
d04a8d4b33 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 16:50:05 +00:00
Benjamin Kramer
05d96f98cb Reduce duplicated hash map lookups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162362 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 15:37:57 +00:00
Craig Topper
96601ca332 Add a getName function to MachineFunction. Use it in places that previously did getFunction()->getName(). Remove includes of Function.h that are no longer needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162347 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 06:07:19 +00:00
Evan Cheng
791e2e0867 Start implementing pre-ra if-converter: using speculation and selects to eliminate branches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158234 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-08 21:53:50 +00:00
Jakob Stoklund Olesen
396618b43a Switch all register list clients to the new MC*Iterator interface.
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
2012-06-01 23:28:30 +00:00
Evan Cheng
3d4166dff0 If-converter models predicated defs as read + write. The read should be marked as 'undef' since it may not already be live. This appeases -verify-machineinstrs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157662 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-30 00:42:02 +00:00
Craig Topper
9ebfbf8b9f Convert more GenRegisterInfo tables from unsigned to uint16_t to reduce static data size.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152016 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-05 05:37:41 +00:00
Andrew Trick
1dd8c8560d Codegen pass definition cleanup. No functionality.
Moving toward a uniform style of pass definition to allow easier target configuration.
Globally declare Pass ID.
Globally declare pass initializer.
Use INITIALIZE_PASS consistently.
Add a call to the initializer from CodeGen.cpp.
Remove redundant "createPass" functions and "getPassName" methods.

While cleaning up declarations, cleaned up comments (sorry for large diff).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150100 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-08 21:23:13 +00:00
Craig Topper
5e25ee8a1f Convert assert(0) to llvm_unreachable
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149816 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-05 08:31:47 +00:00
Evan Cheng
8787c5f24e Add a if-conversion optimization that allows 'true' side of a diamond to be
unpredicated. That is, turn
 subeq  r0, r1, #1
 addne  r0, r1, #1                                                                                                                                                                                                     
into
 sub    r0, r1, #1
 addne  r0, r1, #1

For targets where conditional instructions are always executed, this may be
beneficial. It may remove pseudo anti-dependency in out-of-order execution
CPUs. e.g.
 op    r1, ...
 str   r1, [r10]        ; end-of-life of r1 as div result
 cmp   r0, #65
 movne r1, #44  ; raw dependency on previous r1
 moveq r1, #12

If movne is unpredicated, then
 op    r1, ...
 str   r1, [r10]
 cmp   r0, #65
 mov   r1, #44  ; r1 written unconditionally
 moveq r1, #12

Both mov and moveq are no longer depdendent on the first instruction. This gives
the out-of-order execution engine more freedom to reorder them.

This has passed entire LLVM test suite. But it has not been enabled for any ARM
variant pending more performance evaluation.

rdar://8951196


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146914 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-19 22:01:30 +00:00
Evan Cheng
5a96b3dad2 Add bundle aware API for querying instruction properties and switch the code
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.

For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146026 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07 07:15:52 +00:00
Pete Cooper
9c58aa743d Added missing &. Fixes <rdar://problem/10393723>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143753 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-04 23:49:14 +00:00
Jakub Staszak
0767267790 Fix typo in #include which revealed in the case-sensitive filesystem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136828 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-03 22:53:41 +00:00
Jakub Staszak
990f78d53b Use MachineBranchProbabilityInfo in If-Conversion instead of its own heuristics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136826 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-03 22:34:43 +00:00
Jakub Staszak
4e2710c266 Revert patch which broke some IfConversion tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135738 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-22 00:55:15 +00:00
Jakub Staszak
6b598748b1 Fix typo in #include which revealed in the case-sensitive filesystem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135734 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-22 00:39:00 +00:00
Jakub Staszak
8592d903e1 Use MachineBranchProbabilityInfo instead of MachineLoopInfo in IfConversion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135724 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-21 23:48:55 +00:00
Jakub Staszak
f81b7f6069 Use BranchProbability instead of floating points in IfConverter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134858 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-10 02:58:07 +00:00
Jakub Staszak
2b33f4cbad Don't analyze block if it's not considered for ifcvt anymore.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134856 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-10 02:00:16 +00:00
Evan Cheng
ab8be96fd3 Sink SubtargetFeature and TargetInstrItineraries (renamed MCInstrItineraries) into MC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134049 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-29 01:14:12 +00:00
Evan Cheng
e837dead3c - Rename TargetInstrDesc, TargetOperandInfo to MCInstrDesc and MCOperandInfo and
sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134021 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-28 19:10:37 +00:00
Evan Cheng
cbc988be22 Re-commit 131172 with fix. MachineInstr identity checks should check dead
markers. In some cases a register def is dead on one path, but not on
another.

This is passing Clang self-hosting.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131214 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-12 00:56:58 +00:00
Rafael Espindola
41cdc16e73 Revert 131172 as it is causing clang to miscompile itself. I will try
to provide a reduced testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131176 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-11 03:27:17 +00:00
Evan Cheng
7e20a574eb Add a late optimization to BranchFolding that hoist common instruction sequences
at the start of basic blocks to their common predecessor. It's actually quite
common (e.g. about 50 times in JM/lencod) and has shown to be a nice code size
benefit. e.g.

        pushq   %rax
        testl   %edi, %edi
        jne     LBB0_2
## BB#1:
        xorb    %al, %al
        popq    %rdx
        ret
LBB0_2:
        xorb    %al, %al
        callq   _foo
        popq    %rdx
        ret

=>

        pushq   %rax
        xorb    %al, %al
        testl   %edi, %edi
        je      LBB0_2
## BB#1:
        callq   _foo
LBB0_2:
        popq    %rdx
        ret

rdar://9145558


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131172 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-11 01:03:01 +00:00
Evan Cheng
309db7c947 If converter was being too cute. It look for root BBs (which don't have
successors) and use inverse depth first search to traverse the BBs. However
that doesn't work when the CFG has infinite loops. Simply do a linear
traversal of all BBs work just fine.

rdar://9344645


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130324 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-27 19:32:43 +00:00
Benjamin Kramer
f788854d20 Prune includes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118342 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-06 11:45:59 +00:00
Evan Cheng
8239daf7c8 Two sets of changes. Sorry they are intermingled.
1. Fix pre-ra scheduler so it doesn't try to push instructions above calls to
   "optimize for latency". Call instructions don't have the right latency and
   this is more likely to use introduce spills.
2. Fix if-converter cost function. For ARM, it should use instruction latencies,
   not # of micro-ops since multi-latency instructions is completely executed
   even when the predicate is false. Also, some instruction will be "slower"
   when they are predicated due to the register def becoming implicit input.
   rdar://8598427


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118135 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-03 00:45:17 +00:00
Bob Wilson
7c730e7790 When the "true" and "false" blocks of a diamond if-conversion are the same,
do not double-count the duplicate instructions by counting once from the
beginning and again from the end.  Keep track of where the duplicates from
the beginning ended and don't go past that point when counting duplicates
at the end.  Radar 8589805.

This change causes one of the MC/ARM/simple-fp-encoding tests to produce
different (better!) code without the vmovne instruction being tested.
I changed the test to produce vmovne and vmoveq instructions but moving
between register files in the opposite direction.  That's not quite the same
but predicated versions of those instructions weren't being tested before,
so at least the test coverage is not any worse, just different.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117333 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 00:02:24 +00:00
Bob Wilson
2ad40d3494 Change if-conversion to keep track of the extra cost due to microcoded
instructions separately from the count of non-predicated instructions.  The
instruction count is used in places to determine how many instructions to
copy, predicate, etc. and things get confused if that count includes the
extra cost for microcoded ops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117332 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 00:02:21 +00:00
Owen Anderson
081c34b725 Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19 17:21:58 +00:00
Owen Anderson
2ab36d3502 Begin adding static dependence information to passes, which will allow us to
perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116334 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-12 19:48:12 +00:00
Owen Anderson
ce665bd2e2 Now with fewer extraneous semicolons!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 22:25:06 +00:00
Owen Anderson
e3cc84a43d Thread the determination of branch prediction hit rates back through the if-conversion heuristic APIs. For now,
stick with a constant estimate of 90% (branch predictors are good!), but we might find that we want to provide
more nuanced estimates in the future.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115364 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-01 22:45:50 +00:00
Benjamin Kramer
6406d004c9 Silence msvc warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115097 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-29 22:38:50 +00:00
Owen Anderson
7571ee7885 Give the if-converter access to MachineLoopInfo, and use it to generate plausible branch prediction
estimates.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114981 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-28 20:42:15 +00:00
Owen Anderson
b20b85168c Part one of switching to using a more sane heuristic for determining if-conversion profitability.
Rather than having arbitrary cutoffs, actually try to cost model the conversion.

For now, the constants are tuned to more or less match our existing behavior, but these will be
changed to reflect realistic values as this work proceeds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114973 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-28 18:32:13 +00:00
Evan Cheng
3ef1c8759a Teach if-converter to be more careful with predicating instructions that would
take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113570 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-10 01:29:16 +00:00
Owen Anderson
90c579de5a Reapply r110396, with fixes to appease the Linux buildbot gods.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110460 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 18:33:48 +00:00
Owen Anderson
1f74590e9d Revert r110396 to fix buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110410 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 00:23:35 +00:00
Owen Anderson
9ccaf53ada Don't use PassInfo* as a type identifier for passes. Instead, use the address of the static
ID member as the sole unique type identifier.  Clean up APIs related to this change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110396 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-05 23:42:04 +00:00
Owen Anderson
d13db2c59c Fix batch of converting RegisterPass<> to INTIALIZE_PASS().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109045 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-21 22:09:45 +00:00
Bob Wilson
8eab75f390 Reapply my if-conversion cleanup from svn r106939 with fixes.
There are 2 changes relative to the previous version of the patch:

1) For the "simple" if-conversion case, there's no need to worry about
RemoveExtraEdges not handling an unanalyzable branch.  Predicated terminators
are ignored in this context, so RemoveExtraEdges does the right thing.
This might break someday if we ever treat indirect branches (BRIND) as
predicable, but for now, I just removed this part of the patch, because
in the case where we do not add an unconditional branch, we rely on keeping
the fall-through edge to CvtBBI (which is empty after this transformation).

The change relative to the previous patch is:

@@ -1036,10 +1036,6 @@
     IterIfcvt = false;
   }
 
-  // RemoveExtraEdges won't work if the block has an unanalyzable branch,
-  // which is typically the case for IfConvertSimple, so explicitly remove
-  // CvtBBI as a successor.
-  BBI.BB->removeSuccessor(CvtBBI->BB);
   RemoveExtraEdges(BBI);
 
   // Update block info. BB can be iteratively if-converted.


2) My patch exposed a bug in the code for merging the tail of a "diamond",
which had previously never been exercised.  The code was simply checking that
the tail had a single predecessor, but there was a case in
MultiSource/Benchmarks/VersaBench/dbms where that single predecessor was
neither edge of the diamond.  I added the following change to check for
that:

@@ -1276,7 +1276,18 @@
   // tail, add a unconditional branch to it.
   if (TailBB) {
     BBInfo TailBBI = BBAnalysis[TailBB->getNumber()];
-    if (TailBB->pred_size() == 1 && !TailBBI.HasFallThrough) {
+    bool CanMergeTail = !TailBBI.HasFallThrough;
+    // There may still be a fall-through edge from BBI1 or BBI2 to TailBB;
+    // check if there are any other predecessors besides those.
+    unsigned NumPreds = TailBB->pred_size();
+    if (NumPreds > 1)
+      CanMergeTail = false;
+    else if (NumPreds == 1 && CanMergeTail) {
+      MachineBasicBlock::pred_iterator PI = TailBB->pred_begin();
+      if (*PI != BBI1->BB && *PI != BBI2->BB)
+        CanMergeTail = false;
+    }
+    if (CanMergeTail) {
       MergeBlocks(BBI, TailBBI);
       TailBBI.IsDone = true;
     } else {

With these fixes, I was able to run all the SingleSource and MultiSource
tests successfully.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107110 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-29 00:55:23 +00:00
Jim Grosbach
d459f457b8 new, no longer brain-dead, r106907
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107060 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-28 20:26:00 +00:00