diff options
| -rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index 72ddb07d1e..a46916077a 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -321,11 +321,26 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L) { HasConstantItCount) { // Find out if this predictably varying value is actually used // outside of the loop. "extra" as opposed to "intra". - std::vector<User*> ExtraLoopUsers; + std::vector<Instruction*> ExtraLoopUsers; for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); - UI != E; ++UI) - if (!L->contains(cast<Instruction>(*UI)->getParent())) - ExtraLoopUsers.push_back(*UI); + UI != E; ++UI) { + Instruction *User = cast<Instruction>(*UI); + if (!L->contains(User->getParent())) { + // If this is a PHI node in the exit block and we're inserting, + // into the exit block, it must have a single entry. In this + // case, we can't insert the code after the PHI and have the PHI + // still use it. Instead, don't insert the the PHI. + if (PHINode *PN = dyn_cast<PHINode>(User)) { + // FIXME: This is a case where LCSSA pessimizes code, this + // should be fixed better. + if (PN->getNumOperands() == 2 && + PN->getParent() == BlockToInsertInto) + continue; + } + ExtraLoopUsers.push_back(User); + } + } + if (!ExtraLoopUsers.empty()) { // Okay, this instruction has a user outside of the current loop // and varies predictably in this loop. Evaluate the value it |