diff options
-rw-r--r-- | include/llvm/Analysis/IVUsers.h | 3 | ||||
-rw-r--r-- | lib/Analysis/IVUsers.cpp | 46 | ||||
-rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 13 | ||||
-rw-r--r-- | lib/Transforms/Scalar/LoopStrengthReduce.cpp | 15 | ||||
-rw-r--r-- | lib/Transforms/Utils/SimplifyIndVar.cpp | 6 | ||||
-rw-r--r-- | test/Transforms/LoopStrengthReduce/2012-03-15-nopreheader.ll | 50 |
6 files changed, 115 insertions, 18 deletions
diff --git a/include/llvm/Analysis/IVUsers.h b/include/llvm/Analysis/IVUsers.h index 2a3bb9bc48..11d2cf0ac7 100644 --- a/include/llvm/Analysis/IVUsers.h +++ b/include/llvm/Analysis/IVUsers.h @@ -145,7 +145,8 @@ public: /// AddUsersIfInteresting - Inspect the specified Instruction. If it is a /// reducible SCEV, recursively add its users to the IVUsesByStride set and /// return true. Otherwise, return false. - bool AddUsersIfInteresting(Instruction *I); + bool AddUsersIfInteresting(Instruction *I, + SmallPtrSet<Loop*,16> &SimpleLoopNests); IVStrideUse &AddUser(Instruction *User, Value *Operand); diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp index cad22f8f1a..c598b72c0d 100644 --- a/lib/Analysis/IVUsers.cpp +++ b/lib/Analysis/IVUsers.cpp @@ -79,10 +79,30 @@ static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L, return false; } +/// Return true if this loop and all loop headers that dominate it are in +/// simplified form. +static bool isSimplifiedLoopNest(Loop *L, const DominatorTree *DT, + const LoopInfo *LI) { + if (!L->isLoopSimplifyForm()) + return false; + + for (DomTreeNode *Rung = DT->getNode(L->getLoopPreheader()); + Rung; Rung = Rung->getIDom()) { + BasicBlock *BB = Rung->getBlock(); + const Loop *DomLoop = LI->getLoopFor(BB); + if (DomLoop && DomLoop->getHeader() == BB) { + if (!DomLoop->isLoopSimplifyForm()) + return false; + } + } + return true; +} + /// AddUsersIfInteresting - Inspect the specified instruction. If it is a /// reducible SCEV, recursively add its users to the IVUsesByStride set and /// return true. Otherwise, return false. -bool IVUsers::AddUsersIfInteresting(Instruction *I) { +bool IVUsers::AddUsersIfInteresting(Instruction *I, + SmallPtrSet<Loop*,16> &SimpleLoopNests) { // Add this IV user to the Processed set before returning false to ensure that // all IV users are members of the set. See IVUsers::isIVUserOrOperand. if (!Processed.insert(I)) @@ -117,6 +137,16 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) { if (isa<PHINode>(User) && Processed.count(User)) continue; + Loop *UserLoop = LI->getLoopFor(User->getParent()); + + // Only consider IVUsers that are dominated by simplified loop + // headers. Otherwise, SCEVExpander will crash. + if (UserLoop && !SimpleLoopNests.count(UserLoop)) { + if (!isSimplifiedLoopNest(UserLoop, DT, LI)) + return false; + SimpleLoopNests.insert(UserLoop); + } + // Descend recursively, but not into PHI nodes outside the current loop. // It's important to see the entire expression outside the loop to get // choices that depend on addressing mode use right, although we won't @@ -124,14 +154,15 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) { // If User is already in Processed, we don't want to recurse into it again, // but do want to record a second reference in the same instruction. bool AddUserToIVUsers = false; - if (LI->getLoopFor(User->getParent()) != L) { + if (UserLoop != L) { if (isa<PHINode>(User) || Processed.count(User) || - !AddUsersIfInteresting(User)) { + !AddUsersIfInteresting(User, SimpleLoopNests)) { DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n' << " OF SCEV: " << *ISE << '\n'); AddUserToIVUsers = true; } - } else if (Processed.count(User) || !AddUsersIfInteresting(User)) { + } else if (Processed.count(User) + || !AddUsersIfInteresting(User, SimpleLoopNests)) { DEBUG(dbgs() << "FOUND USER: " << *User << '\n' << " OF SCEV: " << *ISE << '\n'); AddUserToIVUsers = true; @@ -180,11 +211,16 @@ bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) { SE = &getAnalysis<ScalarEvolution>(); TD = getAnalysisIfAvailable<TargetData>(); + // SCEVExpander can only handle users that are dominated by simplified loop + // entries. Keep track of all loops that are only dominated by other simple + // loops so we don't traverse the domtree for each user. + SmallPtrSet<Loop*,16> SimpleLoopNests; + // Find all uses of induction variables in this loop, and categorize // them by stride. Start by finding all of the PHI nodes in the header for // this loop. If they are induction variables, inspect their uses. for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) - (void)AddUsersIfInteresting(I); + (void)AddUsersIfInteresting(I, SimpleLoopNests); return false; } diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index d1e57e101b..490617a0c8 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -450,8 +450,10 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PN) { } // Add a new IVUsers entry for the newly-created integer PHI. - if (IU) - IU->AddUsersIfInteresting(NewPHI); + if (IU) { + SmallPtrSet<Loop*, 16> SimplifiedLoopNests; + IU->AddUsersIfInteresting(NewPHI, SimplifiedLoopNests); + } Changed = true; } @@ -1967,8 +1969,11 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) { // loop exit test instruction. if (IU && NewICmp) { ICmpInst *NewICmpInst = dyn_cast<ICmpInst>(NewICmp); - if (NewICmpInst) - IU->AddUsersIfInteresting(cast<Instruction>(NewICmpInst->getOperand(0))); + if (NewICmpInst) { + SmallPtrSet<Loop*, 16> SimplifiedLoopNests; + IU->AddUsersIfInteresting(cast<Instruction>(NewICmpInst->getOperand(0)), + SimplifiedLoopNests); + } } // Clean up dead instructions. Changed |= DeleteDeadPHIs(L->getHeader()); diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 6768860caa..82d918eeef 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -4534,22 +4534,25 @@ LSRInstance::LSRInstance(const TargetLowering *tli, Loop *l, Pass *P) if (!L->isLoopSimplifyForm()) return; + // If there's no interesting work to be done, bail early. + if (IU.empty()) return; + +#ifndef NDEBUG // All dominating loops must have preheaders, or SCEVExpander may not be able // to materialize an AddRecExpr whose Start is an outer AddRecExpr. // - // FIXME: This is a little absurd. I think LoopSimplify should be taught - // to create a preheader under any circumstance. + // IVUsers analysis should only create users that are dominated by simple loop + // headers. Since this loop should dominate all of its users, its user list + // should be empty if this loop itself is not within a simple loop nest. for (DomTreeNode *Rung = DT.getNode(L->getLoopPreheader()); Rung; Rung = Rung->getIDom()) { BasicBlock *BB = Rung->getBlock(); const Loop *DomLoop = LI.getLoopFor(BB); if (DomLoop && DomLoop->getHeader() == BB) { - if (!DomLoop->getLoopPreheader()) - return; + assert(DomLoop->getLoopPreheader() && "LSR needs a simplified loop nest"); } } - // If there's no interesting work to be done, bail early. - if (IU.empty()) return; +#endif // DEBUG DEBUG(dbgs() << "\nLSR on loop "; WriteAsOperand(dbgs(), L->getHeader(), /*PrintType=*/false); diff --git a/lib/Transforms/Utils/SimplifyIndVar.cpp b/lib/Transforms/Utils/SimplifyIndVar.cpp index 20eef3c0dc..e00565d5f9 100644 --- a/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -231,8 +231,10 @@ void SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem, // Inform IVUsers about the new users. if (IU) { - if (Instruction *I = dyn_cast<Instruction>(Rem->getOperand(0))) - IU->AddUsersIfInteresting(I); + if (Instruction *I = dyn_cast<Instruction>(Rem->getOperand(0))) { + SmallPtrSet<Loop*, 16> SimplifiedLoopNests; + IU->AddUsersIfInteresting(I, SimplifiedLoopNests); + } } DEBUG(dbgs() << "INDVARS: Simplified rem: " << *Rem << '\n'); ++NumElimRem; diff --git a/test/Transforms/LoopStrengthReduce/2012-03-15-nopreheader.ll b/test/Transforms/LoopStrengthReduce/2012-03-15-nopreheader.ll new file mode 100644 index 0000000000..207e9d74f5 --- /dev/null +++ b/test/Transforms/LoopStrengthReduce/2012-03-15-nopreheader.ll @@ -0,0 +1,50 @@ +; RUN: opt -loop-reduce -S < %s | FileCheck %s +; +; <rdar://problem/11049788> Segmentation fault: 11 in LoopStrengthReduce + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64" +target triple = "x86_64-apple-darwin10.0.0" + +; IVUsers should not consider tmp128 a valid user because it is not in a +; simplified loop nest. +; CHECK: @nopreheader +; CHECK: for.cond: +; CHECK: %tmp128 = add i64 %0, %indvar65 +define void @nopreheader(i8* %cmd) nounwind ssp { +entry: + indirectbr i8* undef, [label %while.cond] + +while.cond: ; preds = %while.body, %entry + %0 = phi i64 [ %indvar.next48, %while.body ], [ 0, %entry ] + indirectbr i8* undef, [label %while.end, label %while.body] + +while.body: ; preds = %lor.rhs, %lor.lhs.false17, %lor.lhs.false11, %lor.lhs.false, %land.rhs + %indvar.next48 = add i64 %0, 1 + indirectbr i8* undef, [label %while.cond] + +while.end: ; preds = %lor.rhs, %while.cond + indirectbr i8* undef, [label %if.end152] + +if.end152: ; preds = %lor.lhs.false144, %if.end110 + indirectbr i8* undef, [label %lor.lhs.false184, label %for.cond] + +lor.lhs.false184: ; preds = %lor.lhs.false177 + indirectbr i8* undef, [label %return, label %for.cond] + +for.cond: ; preds = %for.inc, %lor.lhs.false184, %if.end152 + %indvar65 = phi i64 [ %indvar.next66, %for.inc ], [ 0, %lor.lhs.false184 ], [ 0, %if.end152 ] + %tmp128 = add i64 %0, %indvar65 + %s.4 = getelementptr i8* %cmd, i64 %tmp128 + %tmp195 = load i8* %s.4, align 1 + indirectbr i8* undef, [label %return, label %land.rhs198] + +land.rhs198: ; preds = %for.cond + indirectbr i8* undef, [label %return, label %for.inc] + +for.inc: ; preds = %lor.rhs234, %land.lhs.true228, %land.lhs.true216, %land.lhs.true204 + %indvar.next66 = add i64 %indvar65, 1 + indirectbr i8* undef, [label %for.cond] + +return: ; preds = %if.end677, %doshell, %if.then96 + ret void +} |