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b19dd2bcaf
I'm reverting this commit because:
1. As discussed during review, it needs to be rewritten (to avoid creating and
then deleting instructions).
2. This is causing optimizer crashes. Specifically, I'm seeing things like
this:
While deleting: i1 %
Use still stuck around after Def is destroyed: <badref> = select i1 <badref>, i32 0, i32 1
opt: /src/llvm-trunk/lib/IR/Value.cpp:79: virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a value is destroyed!"' failed.
I'd guess that these will go away once we're no longer creating/deleting
instructions here, but just in case, I'm adding a regression test.
Because the code is bring rewritten, I've just XFAIL'd the original regression test. Original commit message:
InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms
Real world code sometimes has the denominator of a 'udiv' be a
'select'. LLVM can handle such cases but only when the 'select'
operands are symmetric in structure (both select operands are a constant
power of two or a left shift, etc.). This falls apart if we are dealt a
'udiv' where the code is not symetric or if the select operands lead us
to more select instructions.
Instead, we should treat the LHS and each select operand as a distinct
divide operation and try to optimize them independently. If we can
to simplify each operation, then we can replace the 'udiv' with, say, a
'lshr' that has a new select with a bunch of new operands for the
select.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185415 91177308-0d34-0410-b5e6-96231b3b80d8
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| ADCE | ||
| ArgumentPromotion | ||
| BBVectorize | ||
| BlockPlacement | ||
| BranchFolding | ||
| CodeExtractor | ||
| CodeGenPrepare | ||
| ConstantMerge | ||
| ConstProp | ||
| CorrelatedValuePropagation | ||
| DeadArgElim | ||
| DeadStoreElimination | ||
| DebugIR | ||
| EarlyCSE | ||
| FunctionAttrs | ||
| GCOVProfiling | ||
| GlobalDCE | ||
| GlobalOpt | ||
| GVN | ||
| IndVarSimplify | ||
| Inline | ||
| InstCombine | ||
| InstSimplify | ||
| Internalize | ||
| IPConstantProp | ||
| JumpThreading | ||
| LCSSA | ||
| LICM | ||
| LoopDeletion | ||
| LoopIdiom | ||
| LoopRotate | ||
| LoopSimplify | ||
| LoopStrengthReduce | ||
| LoopUnroll | ||
| LoopUnswitch | ||
| LoopVectorize | ||
| LowerAtomic | ||
| LowerExpectIntrinsic | ||
| LowerInvoke | ||
| LowerSwitch | ||
| Mem2Reg | ||
| MemCpyOpt | ||
| MergeFunc | ||
| MetaRenamer | ||
| ObjCARC | ||
| PhaseOrdering | ||
| PruneEH | ||
| Reassociate | ||
| Reg2Mem | ||
| ScalarRepl | ||
| SCCP | ||
| SimplifyCFG | ||
| Sink | ||
| SLPVectorizer | ||
| SROA | ||
| StripSymbols | ||
| StructurizeCFG | ||
| TailCallElim | ||
| TailDup | ||