diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/IndVarSimplify.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp index d2ba25637e0..27e377f9037 100644 --- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -70,6 +70,7 @@ namespace { IVUsers *IU; LoopInfo *LI; ScalarEvolution *SE; + DominatorTree *DT; bool Changed; public: @@ -329,6 +330,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) { IU = &getAnalysis<IVUsers>(); LI = &getAnalysis<LoopInfo>(); SE = &getAnalysis<ScalarEvolution>(); + DT = &getAnalysis<DominatorTree>(); Changed = false; // If there are any floating-point recurrences, attempt to @@ -479,12 +481,22 @@ void IndVarSimplify::RewriteIVExpressions(Loop *L, const Type *LargestType, if (!AR->isLoopInvariant(L) && !Stride->isLoopInvariant(L)) continue; + // Determine the insertion point for this user. By default, insert + // immediately before the user. The SCEVExpander class will automatically + // hoist loop invariants out of the loop. For PHI nodes, there may be + // multiple uses, so compute the nearest common dominator for the + // incoming blocks. Instruction *InsertPt = User; if (PHINode *PHI = dyn_cast<PHINode>(InsertPt)) - for (unsigned i = 0; ; ++i) + for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i) if (PHI->getIncomingValue(i) == Op) { - InsertPt = PHI->getIncomingBlock(i)->getTerminator(); - break; + if (InsertPt == User) + InsertPt = PHI->getIncomingBlock(i)->getTerminator(); + else + InsertPt = + DT->findNearestCommonDominator(InsertPt->getParent(), + PHI->getIncomingBlock(i)) + ->getTerminator(); } // Now expand it into actual Instructions and patch it into place. |
