[LV] Minor savings to Sink casts to unravel first order recurrence
Two minor savings: avoid copying the SinkAfter map and avoid moving a cast if it
is not needed.
Differential Revision: https://reviews.llvm.org/D36408
llvm-svn: 310910
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 3c52278..f2015c6 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -565,7 +565,8 @@
auto *I = Phi->user_back();
if (I->isCast() && (I->getParent() == Phi->getParent()) && I->hasOneUse() &&
DT->dominates(Previous, I->user_back())) {
- SinkAfter[I] = Previous;
+ if (!DT->dominates(Previous, I)) // Otherwise we're good w/o sinking.
+ SinkAfter[I] = Previous;
return true;
}
}
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 5c64054..adde819 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -7655,7 +7655,7 @@
// 2. Copy and widen instructions from the old loop into the new loop.
// Move instructions to handle first-order recurrences.
- DenseMap<Instruction *, Instruction *> SinkAfter = Legal->getSinkAfter();
+ DenseMap<Instruction *, Instruction *> &SinkAfter = Legal->getSinkAfter();
for (auto &Entry : SinkAfter) {
Entry.first->removeFromParent();
Entry.first->insertAfter(Entry.second);