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path: root/lib/Transforms/Scalar/LoopRotation.cpp
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2013-05-06Rotate multi-exit loops even if the latch was simplified.Andrew Trick
Test case by Michele Scandale! Fixes PR10293: Load not hoisted out of loop with multiple exits. There are few regressions with this patch, now tracked by rdar:13817079, and a roughly equal number of improvements. The regressions are almost certainly back luck because LoopRotate has very little idea of whether rotation is profitable. Doing better requires a more comprehensive solution. This checkin is a quick fix that lacks generality (PR10293 has a counter-example). But it trivially fixes the case in PR10293 without interfering with other cases, and it does satify the criteria that LoopRotate is a loop canonicalization pass that should avoid heuristics and special cases. I can think of two approaches that would probably be better in the long run. Ultimately they may both make sense. (1) LoopRotate should check that the current header would make a good loop guard, and that the loop does not already has a sufficient guard. The artifical SimplifiedLoopLatch check would be unnecessary, and the design would be more general and canonical. Two difficulties: - We need a strong guarantee that we won't endlessly rotate, so the analysis would need to be precise in order to avoid the SimplifiedLoopLatch precondition. - Analysis like this are usually based on SCEV, which we don't want to rely on. (2) Rotate on-demand in late loop passes. This could even be done by shoving the loop back on the queue after the optimization that needs it. This could work well when we find LICM opportunities in multi-branch loops. This requires some work, and it doesn't really solve the problem of SCEV wanting a loop guard before the analysis. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181230 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-21Switch CodeMetrics itself over to use TTI to determine if an instructionChandler Carruth
is free. The whole CodeMetrics API should probably be reworked more, but this is enough to allow deleting the duplicate code there for computing whether an instruction is free. All of the passes using this have been updated to pull in TTI and hand it to the CodeMetrics stuff. Further, a dead CodeMetrics API (analyzeFunction) is nuked for lack of users. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173036 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02Move all of the header files which are involved in modelling the LLVM IRChandler Carruth
into their new header subdirectory: include/llvm/IR. This matches the directory structure of lib, and begins to correct a long standing point of file layout clutter in LLVM. There are still more header files to move here, but I wanted to handle them in separate commits to make tracking what files make sense at each layer easier. The only really questionable files here are the target intrinsic tablegen files. But that's a battle I'd rather not fight today. I've updated both CMake and Makefile build systems (I think, and my tests think, but I may have missed something). I've also re-sorted the includes throughout the project. I'll be committing updates to Clang, DragonEgg, and Polly momentarily. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20Add a new attribute, 'noduplicate'. If a function contains a noduplicate ↵James Molloy
call, the call cannot be duplicated - Jump threading, loop unrolling, loop unswitching, and loop rotation are inhibited if they would duplicate the call. Similarly inlining of the function is inhibited, if that would duplicate the call (in particular inlining is still allowed when there is only one callsite and the function has internal linkage). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170704 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03Use the new script to sort the includes of every file under lib.Chandler Carruth
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
2012-09-02LoopRotation: Make the brute force DomTree update more brute force.Benjamin Kramer
We update until we hit a fixpoint. This is probably slow but also slightly simplifies the code. It should also fix the occasional invalid domtrees observed when building with expensive checking. I couldn't find a case where this had a measurable slowdown, but if someone finds a pathological case where it does we may have to find a cleverer way of updating dominators here. Thanks to Duncan for the test case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163091 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-01LoopRotation: Check some invariants of the dominator updating code.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163058 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30LoopRotate: Also rotate loops with multiple exits.Benjamin Kramer
The old PHI updating code in loop-rotate was replaced with SSAUpdater a while ago, it has no problems with comples PHIs. What had to be fixed is detecting whether a loop was already rotated and updating dominators when multiple exits were present. This change increases overall code size a bit, mostly due to additional loop unrolling opportunities. Passes test-suite and selfhost with -verify-dom-info. Fixes PR7447. Thanks to Andy for the input on the domtree updating code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162912 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-24Clean whitespaces.Nadav Rotem
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160668 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-16loop-rotate shouldn't hoist alloca instructions out of a loop. Patch by ↵Eli Friedman
Patrik Hägglund, with slightly modified test. Issue reported by Patrik Hägglund on llvmdev. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150642 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-14Add simplifyLoopLatch to LoopRotate pass.Andrew Trick
This folds a simple loop tail into a loop latch. It covers the common (in fortran) case of postincrement loops. It's a "free" way to expose this type of loop to downstream loop optimizations that bail out on non-canonical loops (getLoopLatch is a heavily used check). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150439 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-14whitespaceAndrew Trick
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150438 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-20Make better use of the PHINode API.Jay Foad
Change various bits of code to make better use of the existing PHINode API, to insulate them from forthcoming changes in how PHINodes store their operands. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133434 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-29Preserve line number information.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130536 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-09fix PR9523, a crash in looprotate on a non-canonical loop made out of ↵Chris Lattner
indirectbr. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129203 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-14Do not hoist @llvm.dbg.value. Here, @llvm.dbg.value is "referring" a value ↵Devang Patel
that is modified inside loop. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125529 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11remove a bogus assertion: the latch block of a loop is not Chris Lattner
neccesarily an uncond branch to the header. This fixes PR8955 (the assertion tripping). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123219 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08When loop rotation happens, it is *very* common for the duplicated condbrChris Lattner
to be foldable into an uncond branch. When this happens, we can make a much simpler CFG for the loop, which is important for nested loop cases where we want the outer loop to be aggressively optimized. Handle this case more aggressively. For example, previously on phi-duplicate.ll we would get this: define void @test(i32 %N, double* %G) nounwind ssp { entry: %cmp1 = icmp slt i64 1, 1000 br i1 %cmp1, label %bb.nph, label %for.end bb.nph: ; preds = %entry br label %for.body for.body: ; preds = %bb.nph, %for.cond %j.02 = phi i64 [ 1, %bb.nph ], [ %inc, %for.cond ] %arrayidx = getelementptr inbounds double* %G, i64 %j.02 %tmp3 = load double* %arrayidx %sub = sub i64 %j.02, 1 %arrayidx6 = getelementptr inbounds double* %G, i64 %sub %tmp7 = load double* %arrayidx6 %add = fadd double %tmp3, %tmp7 %arrayidx10 = getelementptr inbounds double* %G, i64 %j.02 store double %add, double* %arrayidx10 %inc = add nsw i64 %j.02, 1 br label %for.cond for.cond: ; preds = %for.body %cmp = icmp slt i64 %inc, 1000 br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge for.cond.for.end_crit_edge: ; preds = %for.cond br label %for.end for.end: ; preds = %for.cond.for.end_crit_edge, %entry ret void } Now we get the much nicer: define void @test(i32 %N, double* %G) nounwind ssp { entry: br label %for.body for.body: ; preds = %entry, %for.body %j.01 = phi i64 [ 1, %entry ], [ %inc, %for.body ] %arrayidx = getelementptr inbounds double* %G, i64 %j.01 %tmp3 = load double* %arrayidx %sub = sub i64 %j.01, 1 %arrayidx6 = getelementptr inbounds double* %G, i64 %sub %tmp7 = load double* %arrayidx6 %add = fadd double %tmp3, %tmp7 %arrayidx10 = getelementptr inbounds double* %G, i64 %j.01 store double %add, double* %arrayidx10 %inc = add nsw i64 %j.01, 1 %cmp = icmp slt i64 %inc, 1000 br i1 %cmp, label %for.body, label %for.end for.end: ; preds = %for.body ret void } With all of these recent changes, we are now able to compile: void foo(char *X) { for (int i = 0; i != 100; ++i) for (int j = 0; j != 100; ++j) X[j+i*100] = 0; } into a single memset of 10000 bytes. This series of changes should also be helpful for other nested loop scenarios as well. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123079 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08split ssa updating code out to its own helper function. Don't botherChris Lattner
moving the OrigHeader block anymore: we just merge it away anyway so its code layout doesn't matter. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123077 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08Implement a TODO: Enhance loopinfo to merge away the unconditional branchChris Lattner
that it was leaving in loops after rotation (between the original latch block and the original header. With this change, it is possible for rotated loops to have just a single basic block, which is useful. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123075 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08inline preserveCanonicalLoopForm now that it is simple.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123073 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08Three major changes:Chris Lattner
1. Rip out LoopRotate's domfrontier updating code. It isn't needed now that LICM doesn't use DF and it is super complex and gross. 2. Make DomTree updating code a lot simpler and faster. The old loop over all the blocks was just to find a block?? 3. Change the code that inserts the new preheader to just use SplitCriticalEdge instead of doing an overcomplex reimplementation of it. No behavior change, except for the name of the inserted preheader. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123072 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08LoopRotate requires canonical loop form, so it always has preheadersChris Lattner
and latch blocks. Reorder entry conditions to make hte pass faster and more logical. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123069 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08use the LI ivar.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123068 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08some cleanups: remove dead arguments and eliminate ivarsChris Lattner
that are just passed to one function. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123067 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08fix an issue duncan pointed out, which could cause loop rotateChris Lattner
to violate LCSSA form git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123066 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08Have loop-rotate simplify instructions (yay instsimplify!) as it clonesChris Lattner
them into the loop preheader, eliminating silly instructions like "icmp i32 0, 100" in fixed tripcount loops. This also better exposes the bigger problem with loop rotate that I'd like to fix: once this has been folded, the duplicated conditional branch *often* turns into an uncond branch. Not aggressively handling this is pessimizing later loop optimizations somethin' fierce by making "dominates all exit blocks" checks fail. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123060 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08Revamp the ValueMapper interfaces in a couple ways:Chris Lattner
1. Take a flags argument instead of a bool. This makes it more clear to the reader what it is used for. 2. Add a flag that says that "remapping a value not in the map is ok". 3. Reimplement MapValue to share a bunch of code and be a lot more efficient. For lookup failures, don't drop null values into the map. 4. Using the new flag a bunch of code can vaporize in LinkModules and LoopUnswitch, kill it. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123058 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08two minor changes: switch to the standard ValueToValueMapTyChris Lattner
map from ValueMapper.h (giving us access to its utilities) and add a fastpath in the loop rotation code, avoiding expensive ssa updator manipulation for values with nothing to update. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123057 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02split dom frontier handling stuff out to its own DominanceFrontier header,Chris Lattner
so that Dominators.h is *just* domtree. Also prune #includes a bit. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122714 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02improve loop rotation to use CodeMetrics to analyze theChris Lattner
size of a loop header instead of its own code size estimator. This allows it to handle bitcasts etc more precisely. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122681 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19Passes do not need to recursively initialize passes that they preserve, ifOwen Anderson
they do not also require them. This allows us to reduce inter-pass linkage dependencies. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116854 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19Get rid of static constructors for pass registration. Instead, every pass ↵Owen Anderson
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
2010-10-12Begin adding static dependence information to passes, which will allow us toOwen Anderson
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
2010-10-07Now with fewer extraneous semicolons!Owen Anderson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-06Teach loop rotate to hoist trivially invariant instructionsChris Lattner
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113134 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-02Reapply commit 112699, speculatively reverted by echristo, sinceDuncan Sands
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112810 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-01Speculatively revert 112699 and 112702, they seem to be causingEric Christopher
self host errors on clang-x86-64. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112719 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-01If PrototypeValue is erased in the middle of using the SSAUpdatorDuncan Sands
then the SSAUpdator may access freed memory. Instead, simply pass in the type and name explicitly, which is all that was used anyway. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112699 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17When rotating loops, put the original header at the bottom of theDan Gohman
loop, making the resulting loop significantly less ugly. Also, zap its trivial PHI nodes, since it's easy. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111255 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06Reapply r110396, with fixes to appease the Linux buildbot gods.Owen Anderson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110460 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06Revert r110396 to fix buildbots.Owen Anderson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110410 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-05Don't use PassInfo* as a type identifier for passes. Instead, use the ↵Owen Anderson
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
2010-07-21Fix batch of converting RegisterPass<> to INTIALIZE_PASS().Owen Anderson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109045 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-16Reorder the contents of various getAnalysisUsage functions, eliminatingDan Gohman
a redundant loopsimplify run from the default -O2 sequence. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108539 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-22Use pre-increment instead of post-increment when the result is not used.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106542 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-05Update various Loop optimization passes to cope with the possibility thatDan Gohman
LoopSimplify form may not be available. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86175 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-05Call getAnalysis<LoopInfo> the normal way, instead of asking passed-inDan Gohman
LoopPassManager for it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86163 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-31Rename forgetLoopBackedgeTakenCount to forgetLoop, because itDan Gohman
clears out more information than just the stored backedge taken count. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85664 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-26Fix a typo in a comment.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85120 91177308-0d34-0410-b5e6-96231b3b80d8
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