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* [LPM] Make LCSSA a utility with a FunctionPass that applies it to allChandler Carruth2014-01-251-161/+192
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | the loops in a function, and teach LICM to work in the presance of LCSSA. Previously, LCSSA was a loop pass. That made passes requiring it also be loop passes and unable to depend on function analysis passes easily. It also caused outer loops to have a different "canonical" form from inner loops during analysis. Instead, we go into LCSSA form and preserve it through the loop pass manager run. Note that this has the same problem as LoopSimplify that prevents enabling its verification -- loop passes which run at the end of the loop pass manager and don't preserve these are valid, but the subsequent loop pass runs of outer loops that do preserve this pass trigger too much verification and fail because the inner loop no longer verifies. The other problem this exposed is that LICM was completely unable to handle LCSSA form. It didn't preserve it and it actually would give up on moving instructions in many cases when they were used by an LCSSA phi node. I've taught LICM to support detecting LCSSA-form PHI nodes and to hoist and sink around them. This may actually let LICM fire significantly more because we put everything into LCSSA form to rotate the loop before running LICM. =/ Now LICM should handle that fine and preserve it correctly. The down side is that LICM has to require LCSSA in order to preserve it. This is just a fact of life for LCSSA. It's entirely possible we should completely remove LCSSA from the optimizer. The test updates are essentially accomodating LCSSA phi nodes in the output of LICM, and the fact that we now completely sink every instruction in ashr-crash below the loop bodies prior to unrolling. With this change, LCSSA is computed only three times in the pass pipeline. One of them could be removed (and potentially a SCEV run and a separate LoopPassManager entirely!) if we had a LoopPass variant of InstCombine that ran InstCombine on the loop body but refused to combine away LCSSA PHI nodes. Currently, this also prevents loop unrolling from being in the same loop pass manager is rotate, LICM, and unswitch. There is one thing that I *really* don't like -- preserving LCSSA in LICM is quite expensive. We end up having to re-run LCSSA twice for some loops after LICM runs because LICM can undo LCSSA both in the current loop and the parent loop. I don't really see good solutions to this other than to completely move away from LCSSA and using tools like SSAUpdater instead. llvm-svn: 200067
* Fix known typosAlp Toker2014-01-242-4/+4
| | | | | | | Sweep the codebase for common typos. Includes some changes to visible function names that were misspelt. llvm-svn: 200018
* [LPM] Make LoopSimplify no longer a LoopPass and instead both a utilityChandler Carruth2014-01-232-385/+452
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | function and a FunctionPass. This has many benefits. The motivating use case was to be able to compute function analysis passes *after* running LoopSimplify (to avoid invalidating them) and then to run other passes which require LoopSimplify. Specifically passes like unrolling and vectorization are critical to wire up to BranchProbabilityInfo and BlockFrequencyInfo so that they can be profile aware. For the LoopVectorize pass the only things in the way are LoopSimplify and LCSSA. This fixes LoopSimplify and LCSSA is next on my list. There are also a bunch of other benefits of doing this: - It is now very feasible to make more passes *preserve* LoopSimplify because they can simply run it after changing a loop. Because subsequence passes can assume LoopSimplify is preserved we can reduce the runs of this pass to the times when we actually mutate a loop structure. - The new pass manager should be able to more easily support loop passes factored in this way. - We can at long, long last observe that LoopSimplify is preserved across SCEV. This *halves* the number of times we run LoopSimplify!!! Now, getting here wasn't trivial. First off, the interfaces used by LoopSimplify are all over the map regarding how analysis are updated. We end up with weird "pass" parameters as a consequence. I'll try to clean at least some of this up later -- I'll have to have it all clean for the new pass manager. Next up I discovered a really frustrating bug. LoopUnroll *claims* to preserve LoopSimplify. That's actually a lie. But the way the LoopPassManager ends up running the passes, it always ran LoopSimplify on the unrolled-into loop, rectifying this oversight before any verification could kick in and point out that in fact nothing was preserved. So I've added code to the unroller to *actually* simplify the surrounding loop when it succeeds at unrolling. The only functional change in the test suite is that we now catch a case that was previously missed because SCEV and other loop transforms see their containing loops as simplified and thus don't miss some opportunities. One test case has been converted to check that we catch this case rather than checking that we miss it but at least don't get the wrong answer. Note that I have #if-ed out all of the verification logic in LoopSimplify! This is a temporary workaround while extracting these bits from the LoopPassManager. Currently, there is no way to have a pass in the LoopPassManager which preserves LoopSimplify along with one which does not. The LPM will try to verify on each loop in the nest that LoopSimplify holds but the now-Function-pass cannot distinguish what loop is being verified and so must try to verify all of them. The inner most loop is clearly no longer simplified as there is a pass which didn't even *attempt* to preserve it. =/ Once I get LCSSA out (and maybe LoopVectorize and some other fixes) I'll be able to re-enable this check and catch any places where we are still failing to preserve LoopSimplify. If this causes problems I can back this out and try to commit *all* of this at once, but so far this seems to work and allow much more incremental progress. llvm-svn: 199884
* Switch-to-lookup tables: set threshold to 3 casesHans Wennborg2014-01-151-5/+3
| | | | | | | | | | | | | | | There has been an old FIXME to find the right cut-off for when it's worth analyzing and potentially transforming a switch to a lookup table. The switches always have two or more cases. I could not measure any speed-up by transforming a switch with two cases. A switch with three cases gets a nice speed-up, and I couldn't measure any compile-time regression, so I think this is the right threshold. In a Clang self-host, this causes 480 new switches to be transformed, and reduces the final binary size with 8 KB. llvm-svn: 199294
* [PM] Split DominatorTree into a concrete analysis result object whichChandler Carruth2014-01-138-33/+43
| | | | | | | | | | | | | | | | | | | | | | | can be used by both the new pass manager and the old. This removes it from any of the virtual mess of the pass interfaces and lets it derive cleanly from the DominatorTreeBase<> template. In turn, tons of boilerplate interface can be nuked and it turns into a very straightforward extension of the base DominatorTree interface. The old analysis pass is now a simple wrapper. The names and style of this split should match the split between CallGraph and CallGraphWrapperPass. All of the users of DominatorTree have been updated to match using many of the same tricks as with CallGraph. The goal is that the common type remains the resulting DominatorTree rather than the pass. This will make subsequent work toward the new pass manager significantly easier. Also in numerous places things became cleaner because I switched from re-running the pass (!!! mid way through some other passes run!!!) to directly recomputing the domtree. llvm-svn: 199104
* [cleanup] Move the Dominators.h and Verifier.h headers into the IRChandler Carruth2014-01-1311-12/+12
| | | | | | | | | | | | | | | | | | directory. These passes are already defined in the IR library, and it doesn't make any sense to have the headers in Analysis. Long term, I think there is going to be a much better way to divide these matters. The dominators code should be fully separated into the abstract graph algorithm and have that put in Support where it becomes obvious that evn Clang's CFGBlock's can use it. Then the verifier can manually construct dominance information from the Support-driven interface while the Analysis library can provide a pass which both caches, reconstructs, and supports a nice update API. But those are very long term, and so I don't want to leave the really confusing structure until that day arrives. llvm-svn: 199082
* Switch-to-lookup tables: Don't require a result for the defaultHans Wennborg2014-01-121-12/+25
| | | | | | | | | | | | | | | | | | | | | | | case when the lookup table doesn't have any holes. This means we can build a lookup table for switches like this: switch (x) { case 0: return 1; case 1: return 2; case 2: return 3; case 3: return 4; default: exit(1); } The default case doesn't yield a constant result here, but that doesn't matter, since a default result is only necessary for filling holes in the lookup table, and this table doesn't have any holes. This makes us transform 505 more switches in a clang bootstrap, and shaves 164 KB off the resulting clang binary. llvm-svn: 199025
* Re-sort all of the includes with ./utils/sort_includes.py so thatChandler Carruth2014-01-075-6/+6
| | | | | | | | | | subsequent changes are easier to review. About to fix some layering issues, and wanted to separate out the necessary churn. Also comment and sink the include of "Windows.h" in three .inc files to match the usage in Memory.inc. llvm-svn: 198685
* Reapply r198478 "Fix PR18361: Invalidate LoopDispositions after LoopSimplify ↵Andrew Trick2014-01-061-7/+14
| | | | | | | | | | hoists things." Now with a fix for PR18384: ValueHandleBase::ValueIsDeleted. We need to invalidate SCEV's loop info when we delete a block, even if no values are hoisted. llvm-svn: 198631
* Revert "Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists ↵Alp Toker2014-01-041-17/+10
| | | | | | | | | | | | | | | | | things." This commit was the source of crasher PR18384: While deleting: label %for.cond127 An asserting value handle still pointed to this value! UNREACHABLE executed at llvm/lib/IR/Value.cpp:671! Reverting to get the builders green, feel free to re-land after fixing up. (Renato has a handy isolated repro if you need it.) This reverts commit r198478. llvm-svn: 198503
* Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things.Andrew Trick2014-01-041-10/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | getSCEV for an ashr instruction creates an intermediate zext expression when it truncates its operand. The operand is initially inside the loop, so the narrow zext expression has a non-loop-invariant loop disposition. LoopSimplify then runs on an outer loop, hoists the ashr operand, and properly invalidate the SCEVs that are mapped to value. The SCEV expression for the ashr is now an AddRec with the hoisted value as the now loop-invariant start value. The LoopDisposition of this wide value was properly invalidated during LoopSimplify. However, if we later get the ashr SCEV again, we again try to create the intermediate zext expression. We get the same SCEV that we did earlier, and it is still cached because it was never mapped to a Value. When we try to create a new AddRec we abort because we're using the old non-loop-invariant LoopDisposition. I don't have a solution for this other than to clear LoopDisposition when LoopSimplify hoists things. I think the long-term strategy should be to perform LoopSimplify on all loops before computing SCEV and before running any loop opts on individual loops. It's possible we may want to rerun LoopSimplify on individual loops, but it should rarely do anything, so rarely require invalidating SCEV. llvm-svn: 198478
* Add support to indvars for optimizing sadd.with.overflow.Andrew Trick2013-12-231-1/+81
| | | | | | | | | | | | | | | | Split sadd.with.overflow into add + sadd.with.overflow to allow analysis and optimization. This should ideally be done after InstCombine, which can perform code motion (eventually indvars should run after all canonical instcombines). We want ISEL to recombine the add and the check, at least on x86. This is currently under an option for reducing live induction variables: -liv-reduce. The next step is reducing liveness of IVs that are live out of the overflow check paths. Once the related optimizations are fully developed, reviewed and tested, I do expect this to become default. llvm-svn: 197926
* [asan] don't unpoison redzones on function exit in use-after-return mode.Kostya Serebryany2013-12-231-0/+33
| | | | | | | | | | | | | | | | | | | | | | | | Summary: Before this change the instrumented code before Ret instructions looked like: <Unpoison Frame Redzones> if (Frame != OriginalFrame) // I.e. Frame is fake <Poison Complete Frame> Now the instrumented code looks like: if (Frame != OriginalFrame) // I.e. Frame is fake <Poison Complete Frame> else <Unpoison Frame Redzones> Reviewers: eugenis Reviewed By: eugenis CC: llvm-commits Differential Revision: http://llvm-reviews.chandlerc.com/D2458 llvm-svn: 197907
* Transforms: Don't create bad weights when eliminating dead casesJustin Bogner2013-12-201-1/+1
| | | | | | | | | If we happen to eliminate every case in a switch that has branch weights, we currently try to create metadata for the one remaining branch, triggering an assert. Instead, we need to check that the metadata we're trying to create is sensible. llvm-svn: 197791
* Add an explicit insert point argument to SplitBlockAndInsertIfThen.Evgeniy Stepanov2013-12-191-9/+10
| | | | | | | | Currently SplitBlockAndInsertIfThen requires that branch condition is an Instruction itself, which is very inconvenient, because it is sometimes an Operator, or even a Constant. llvm-svn: 197677
* Enable double to float shrinking optimizations for binary functions like ↵Yi Jiang2013-12-162-9/+86
| | | | | | 'fmin/fmax'. Fix radar:15283121 llvm-svn: 197434
* Resubmit r196544: Apply transformation on OS X 10.9+ and iOS 7.0+: pow(10, ↵Yi Jiang2013-12-121-0/+6
| | | | | | x) ―> __exp10(x) llvm-svn: 197109
* Transforms: Don't create bad branch weights when folding a switchJustin Bogner2013-12-101-2/+4
| | | | | | | | This avoids creating branch weight metadata of length one when we fold cases into the default of a switch instruction, which was triggering an assert. llvm-svn: 196845
* Revert 196544 due to internal bot failures.Manman Ren2013-12-081-6/+0
| | | | llvm-svn: 196732
* Fix inlining to not lose the "cleanup" clause from landingpadsMark Seaborn2013-12-081-0/+2
| | | | | | | This fixes PR17872. This bug can lead to C++ destructors not being called when they should be, when an exception is thrown. llvm-svn: 196711
* Fix inlining to not produce duplicate landingpad clausesMark Seaborn2013-12-081-20/+12
| | | | | | | | | | | | | | | | | | | | | | | Before this change, inlining one "invoke" into an outer "invoke" call site can lead to the outer landingpad's catch/filter clauses being copied multiple times into the resulting landingpad. This happens: * when the inlined function contains multiple "resume" instructions, because forwardResume() copies the clauses but is called multiple times; * when the inlined function contains a "resume" and a "call", because HandleCallsInBlockInlinedThroughInvoke() copies the clauses but is redundant with forwardResume(). Fix this by deduplicating the code. This problem doesn't lead to any incorrect execution; it's only untidy. This change will make fixing PR17872 a little easier. llvm-svn: 196710
* Don't #include heavy Dominators.h file in LoopInfo.h. This change reducesJakub Staszak2013-12-071-0/+1
| | | | | | overall time of LLVM compilation by ~1%. llvm-svn: 196667
* [asan] fix ndebug build with strict warnings (-Wunused-variable)Kostya Serebryany2013-12-061-0/+1
| | | | llvm-svn: 196574
* [asan] rewrite asan's stack frame layoutKostya Serebryany2013-12-062-0/+114
| | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Rewrite asan's stack frame layout. First, most of the stack layout logic is moved into a separte file to make it more testable and (potentially) useful for other projects. Second, make the frames more compact by using adaptive redzones (smaller for small objects, larger for large objects). Third, try to minimized gaps due to large alignments (this is hypothetical since today we don't see many stack vars aligned by more than 32). The frames indeed become more compact, but I'll still need to run more benchmarks before committing, but I am sking for review now to get early feedback. This change will be accompanied by a trivial change in compiler-rt tests to match the new frame sizes. Reviewers: samsonov, dvyukov Reviewed By: samsonov CC: llvm-commits Differential Revision: http://llvm-reviews.chandlerc.com/D2324 llvm-svn: 196568
* Apply transformation on OS X 10.9+ and iOS 7.0+: pow(10, x) ―> __exp10(x)Yi Jiang2013-12-051-0/+6
| | | | llvm-svn: 196544
* Correct word hyphenationsAlp Toker2013-12-051-2/+2
| | | | | | | This patch tries to avoid unrelated changes other than fixing a few hyphen-related ambiguities and contractions in nearby lines. llvm-svn: 196471
* InlineFunction.cpp: Remove a return value that is always falseMark Seaborn2013-12-021-11/+3
| | | | | | | | Remove some associated dead code. This cleanup is associated with PR17872. llvm-svn: 196147
* Add support for software expansion of 64-bit integer division instructions.Michael Ilseman2013-11-191-45/+199
| | | | | | Patch by Dmitri Shtilman! llvm-svn: 195116
* Debug info: Let LowerDbgDeclare perfom the dbg.declare -> dbg.valueAdrian Prantl2013-11-181-1/+5
| | | | | | | | | | lowering only for load/stores to scalar allocas. The resulting values confuse the backend and don't add anything because we can describe array-allocas with a dbg.declare intrinsic just fine. rdar://problem/15464571 llvm-svn: 195052
* Utils/LoopUnroll.cpp: Tweak (StringRef)OldName to be valid until it is used, ↵NAKAMURA Takumi2013-11-171-1/+3
| | | | | | | | since r194601. eraseFromParent() invalidates OldName. llvm-svn: 194970
* Add the cold attribute to error-reporting call sitesHal Finkel2013-11-171-0/+72
| | | | | | | | | | | Generally speaking, control flow paths with error reporting calls are cold. So far, error reporting calls are calls to perror and calls to fprintf, fwrite, etc. with stderr as the stream. This can be extended in the future. The primary motivation is to improve block placement (the cold attribute affects the static branch prediction heuristics). llvm-svn: 194943
* Use StringRef instead of std::stringJakub Staszak2013-11-131-1/+1
| | | | llvm-svn: 194601
* FoldBranchToCommonDest merges branches into a single branch with or/and of ↵Nadav Rotem2013-11-121-2/+7
| | | | | | the condition. It has a heuristics for estimating when some of the dependencies are processed by out-of-order processors. This patch adds another rule to the heuristics that says that if the "BonusInstruction" that we speculatively execute is used by the condition of the second branch then it is okay to hoist it. This change exposes more opportunities for other passes to transform the code. It does not matter that much that we if-convert the code because the selectiondag builder splits or/and branches into multiple branches when profitable. llvm-svn: 194524
* SimplifyCFG: Use existing constant folding logic when forming switch tables.Benjamin Kramer2013-11-121-31/+20
| | | | | | Both simpler and more powerful than the hand-rolled folding logic. llvm-svn: 194475
* Use type form of getIntPtrType.Matt Arsenault2013-11-101-1/+1
| | | | | | | | This should be inconsequential and is work towards removing the default address space arguments. llvm-svn: 194347
* SimplifyCFG has a heuristics for out-of-order processors that decides when ↵Nadav Rotem2013-11-101-1/+1
| | | | | | | | it is worthwhile to merge branches. It tries to estimate if the operands of the instruction that we want to hoist are ready. This commit marks function arguments as 'ready' because they require no calculation. This boosts libquantum and a few other workloads from the testsuite. llvm-svn: 194346
* Revert "Inliner: Handle readonly attribute per argument when adding memcpy"David Majnemer2013-11-031-13/+10
| | | | | | | | This reverts commit r193356, it caused PR17781. A reduced test case covering this regression has been added to the test suite. llvm-svn: 193955
* Convert calls to __sinpi and __cospi into __sincospi_stretBob Wilson2013-11-031-0/+156
| | | | | | | | | | This adds an SimplifyLibCalls case which converts the special __sinpi and __cospi (float & double variants) into a __sincospi_stret where appropriate to remove duplicated work. Patch by Tim Northover llvm-svn: 193943
* Do not convert "call asm" to "invoke asm" in Inliner.Manman Ren2013-10-311-1/+2
| | | | | | | | | | | | | | | | Given that backend does not handle "invoke asm" correctly ("invoke asm" will be handled by SelectionDAGBuilder::visitInlineAsm, which does not have the right setup for LPadToCallSiteMap) and we already made the assumption that inline asm does not throw in InstCombiner::visitCallSite, we are going to make the same assumption in Inliner to make sure we don't convert "call asm" to "invoke asm". If it becomes necessary to add support for "invoke asm" later on, we will need to modify the backend as well as remove the assumptions that inline asm does not throw. Fix rdar://15317907 llvm-svn: 193808
* Quick look-up for block in loop.Wan Xiaofei2013-10-261-13/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements quick look-up for block in loop by maintaining a hash set for blocks. It improves the efficiency of loop analysis a lot, the biggest improvement could be 5-6%(458.sjeng). Below are the compilation time for our benchmark in llc before & after the patch. Benchmark llc - trunk llc - patched 401.bzip2 0.339081 100.00% 0.329657 102.86% 403.gcc 19.853966 100.00% 19.605466 101.27% 429.mcf 0.049823 100.00% 0.048451 102.83% 433.milc 0.514898 100.00% 0.510217 100.92% 444.namd 1.109328 100.00% 1.103481 100.53% 445.gobmk 4.988028 100.00% 4.929114 101.20% 456.hmmer 0.843871 100.00% 0.825865 102.18% 458.sjeng 0.754238 100.00% 0.714095 105.62% 464.h264ref 2.9668 100.00% 2.90612 102.09% 471.omnetpp 4.556533 100.00% 4.511886 100.99% bitmnp01 0.038168 100.00% 0.0357 106.91% idctrn01 0.037745 100.00% 0.037332 101.11% libquake2 3.78689 100.00% 3.76209 100.66% libquake_ 2.251525 100.00% 2.234104 100.78% linpack 0.033159 100.00% 0.032788 101.13% matrix01 0.045319 100.00% 0.043497 104.19% nbench 0.333161 100.00% 0.329799 101.02% tblook01 0.017863 100.00% 0.017666 101.12% ttsprk01 0.054337 100.00% 0.053057 102.41% Reviewer : Andrew Trick <atrick@apple.com>, Hal Finkel <hfinkel@anl.gov> Approver : Andrew Trick <atrick@apple.com> Test : Pass make check-all & llvm test-suite llvm-svn: 193460
* Handle calls and invokes in GlobalStatus.Rafael Espindola2013-10-251-0/+5
| | | | | | | | | | | This patch teaches GlobalStatus to analyze a call that uses the global value as a callee, not as an argument. With this change internalize call handle the common use of linkonce_odr functions. This reduces the number of linkonce_odr functions in a LTO build of clang (checked with the emit-llvm gold plugin option) from 1730 to 60. llvm-svn: 193436
* Inliner: Handle readonly attribute per argument when adding memcpyTom Stellard2013-10-241-10/+13
| | | | | | Patch by: Vincent Lejeune llvm-svn: 193356
* SimplifyCFG: Don't duplicate calls to functions marked noduplicate v2Tom Stellard2013-10-211-0/+15
| | | | | | | v2: - Use CI->cannotDuplicate() llvm-svn: 193115
* Teach SimplifyCFG about address spacesMatt Arsenault2013-10-211-5/+9
| | | | llvm-svn: 193104
* Optimize more linkonce_odr values during LTO.Rafael Espindola2013-10-212-0/+179
| | | | | | | | | | | When a linkonce_odr value that is on the dso list is not unnamed_addr we can still look to see if anything is actually using its address. If not, it is safe to hide it. This patch implements that by moving GlobalStatus to Transforms/Utils and using it in Internalize. llvm-svn: 193090
* Fix the predecessor removal logic in r193045.Michael Gottesman2013-10-211-11/+9
| | | | | | Additionally some small comment/stylistic fixes are included as well. llvm-svn: 193068
* Don't eliminate a partially redundant load if it's in a landing pad.Bill Wendling2013-10-211-14/+1
| | | | | | | | | | | | A landing pad can be jumped to only by the unwind edge of an invoke instruction. If we eliminate a partially redundant load in a landing pad, it will create a basic block that violates this constraint. It then leads to other problems down the line if it tries to merge that basic block with the landing pad. Avoid this by not eliminating the load in a landing pad. PR17621 llvm-svn: 193064
* Teach simplify-cfg how to correctly create covered lookup tables for ↵Michael Gottesman2013-10-201-6/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | switches on iN with N >= 3. One optimization simplify-cfg performs is the converting of switches to lookup tables if the switch has > 4 cases. This is done by: 1. Finding the max/min case value and calculating the switch case range. 2. Create a lookup table basic block. 3. Perform a check in the switch's BB to see if the input value is in the switch's case range. If the input value satisfies said predicate branch to the lookup table BB, otherwise branch to the switch's default destination BB using the default value as the result. The conditional check consists of subtracting the min case value of the table from any input iN value and then ensuring that said value is unsigned less than the size of the lookup table represented as an iN value. If the lookup table is a covered lookup table, the size of the table will be N which is 0 as an iN value. Thus the comparison will be an `icmp ult` of an iN value against 0 which is always false yielding the incorrect result. This patch fixes this problem by recognizing if we have a covered lookup table and if we do, unconditionally jumps to the lookup table BB since the covering property of the lookup table implies no input values could not be handled by said BB. rdar://15268442 llvm-svn: 193045
* Perform an intelligent splice of the predecessor with the single successor.Bill Wendling2013-10-191-1/+14
| | | | | | | | If the predecessor's being spliced into a landing pad, then we need the PHIs to come first and the rest of the predecessor's code to come *after* the landing pad instruction. llvm-svn: 193035
* Basic blocks typically have few predecessors. Use a SmallDenseMap toChris Lattner2013-10-141-3/+3
| | | | | | avoid a heap allocation when this is the case. llvm-svn: 192602
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