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[LV] Preserve LoopInfo when store predication is used 

This was a latent bug that got exposed by the change to add LoopSimplify
as a dependence to LoopLoadElimination.  Since LoopInfo was corrupted
after LV, LoopSimplify mis-compiled nbench in the test-suite (more
details in the PR).

The problem was that when we create the blocks for predicated stores we
didn't add those to any loops.

The original testcase for store predication provides coverage for this
assuming we verify LI on the way out of LV.

Fixes PR26952.

llvm-svn: 263565
This commit is contained in:
Adam Nemet 2016-03-15 18:06:20 +00:00
parent dfdf278ebf
commit fdb20595a1
4 changed files with 18 additions and 12 deletions
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5
llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
View File

@ -259,11 +259,12 @@ ReturnInst *FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
/// UnreachableInst, otherwise it branches to Tail.
/// Returns the NewBasicBlock's terminator.
///
/// Updates DT if given.
/// Updates DT and LI if given.
TerminatorInst *SplitBlockAndInsertIfThen(Value *Cond, Instruction *SplitBefore,
bool Unreachable,
MDNode *BranchWeights = nullptr,
DominatorTree *DT = nullptr);
DominatorTree *DT = nullptr,
LoopInfo *LI = nullptr);
/// SplitBlockAndInsertIfThenElse is similar to SplitBlockAndInsertIfThen,
/// but also creates the ElseBlock.

15
llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
View File

@ -709,11 +709,10 @@ ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
/// UnreachableInst, otherwise it branches to Tail.
/// Returns the NewBasicBlock's terminator.
TerminatorInst *llvm::SplitBlockAndInsertIfThen(Value *Cond,
Instruction *SplitBefore,
bool Unreachable,
MDNode *BranchWeights,
DominatorTree *DT) {
TerminatorInst *
llvm::SplitBlockAndInsertIfThen(Value *Cond, Instruction *SplitBefore,
bool Unreachable, MDNode *BranchWeights,
DominatorTree *DT, LoopInfo *LI) {
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Tail = Head->splitBasicBlock(SplitBefore->getIterator());
TerminatorInst *HeadOldTerm = Head->getTerminator();
@ -743,6 +742,12 @@ TerminatorInst *llvm::SplitBlockAndInsertIfThen(Value *Cond,
}
}
if (LI) {
Loop *L = LI->getLoopFor(Head);
L->addBasicBlockToLoop(ThenBlock, *LI);
L->addBasicBlockToLoop(Tail, *LI);
}
return CheckTerm;
}

2
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
View File

@ -3628,7 +3628,7 @@ void InnerLoopVectorizer::vectorizeLoop() {
BasicBlock::iterator I(KV.first);
auto *BB = SplitBlock(I->getParent(), &*std::next(I), DT, LI);
auto *T = SplitBlockAndInsertIfThen(KV.second, &*I, /*Unreachable=*/false,
/*BranchWeights=*/nullptr, DT);
/*BranchWeights=*/nullptr, DT, LI);
I->moveBefore(T);
I->getParent()->setName("pred.store.if");
BB->setName("pred.store.continue");

8
llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
View File

@ -1,7 +1,7 @@
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=1 -force-vector-interleave=2 -loop-vectorize -simplifycfg < %s | FileCheck %s --check-prefix=UNROLL
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=1 -force-vector-interleave=2 -loop-vectorize < %s | FileCheck %s --check-prefix=UNROLL-NOSIMPLIFY
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=2 -force-vector-interleave=1 -loop-vectorize -enable-cond-stores-vec -simplifycfg < %s | FileCheck %s --check-prefix=VEC
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=2 -force-vector-interleave=1 -loop-vectorize -enable-cond-stores-vec -simplifycfg -instcombine < %s | FileCheck %s --check-prefix=VEC-IC
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=1 -force-vector-interleave=2 -loop-vectorize -verify-loop-info -simplifycfg < %s | FileCheck %s --check-prefix=UNROLL
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=1 -force-vector-interleave=2 -loop-vectorize -verify-loop-info < %s | FileCheck %s --check-prefix=UNROLL-NOSIMPLIFY
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=2 -force-vector-interleave=1 -loop-vectorize -enable-cond-stores-vec -verify-loop-info -simplifycfg < %s | FileCheck %s --check-prefix=VEC
; RUN: opt -S -vectorize-num-stores-pred=1 -force-vector-width=2 -force-vector-interleave=1 -loop-vectorize -enable-cond-stores-vec -verify-loop-info -simplifycfg -instcombine < %s | FileCheck %s --check-prefix=VEC-IC
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.9.0"