[llvm] 4abdb85 - [SSAUpdater] Avoid un-necessary SmallVector stores (#97820)
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Tue Jul 16 04:28:40 PDT 2024
Author: Jeremy Morse
Date: 2024-07-16T12:28:37+01:00
New Revision: 4abdb85ef2b659a0ee919a4509dd6a82901351b5
URL: https://github.com/llvm/llvm-project/commit/4abdb85ef2b659a0ee919a4509dd6a82901351b5
DIFF: https://github.com/llvm/llvm-project/commit/4abdb85ef2b659a0ee919a4509dd6a82901351b5.diff
LOG: [SSAUpdater] Avoid un-necessary SmallVector stores (#97820)
The default template for the generic IDF calculator fetching
block-children will, by default:
* Fetch the children range from the relevant `GraphTraits`,
* Store all child nodes in a `SmallVector`,
* Return that `SmallVector` into the IDF calculator.
The only place this `SmallVector` is used is in a for-range loop... thus
there's no reason why we can't just iterate over the child range from
`GraphTraits`, instead of storing all the nodes locally then iterating
over the local copy. (If the children of a node change during IDF
calculation, everything is broken anyway).
This yields a 0.14% debug-info build performance improvement on the
compile time tracker, as InstrRefBasedLDV uses the SSA updater
intensively on all functions.
Added:
Modified:
llvm/include/llvm/Support/GenericIteratedDominanceFrontier.h
Removed:
################################################################################
diff --git a/llvm/include/llvm/Support/GenericIteratedDominanceFrontier.h b/llvm/include/llvm/Support/GenericIteratedDominanceFrontier.h
index 0dc58e37c821d..cb18d5b0c265a 100644
--- a/llvm/include/llvm/Support/GenericIteratedDominanceFrontier.h
+++ b/llvm/include/llvm/Support/GenericIteratedDominanceFrontier.h
@@ -25,6 +25,7 @@
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/GenericDomTree.h"
#include <queue>
@@ -37,9 +38,10 @@ namespace IDFCalculatorDetail {
/// successors.
template <class NodeTy, bool IsPostDom> struct ChildrenGetterTy {
using NodeRef = typename GraphTraits<NodeTy *>::NodeRef;
- using ChildrenTy = SmallVector<NodeRef, 8>;
+ using ChildIteratorType = typename GraphTraits<NodeTy *>::ChildIteratorType;
+ using range = iterator_range<ChildIteratorType>;
- ChildrenTy get(const NodeRef &N);
+ range get(const NodeRef &N);
};
} // end of namespace IDFCalculatorDetail
@@ -115,13 +117,12 @@ template <class NodeTy, bool IsPostDom> class IDFCalculatorBase {
namespace IDFCalculatorDetail {
template <class NodeTy, bool IsPostDom>
-typename ChildrenGetterTy<NodeTy, IsPostDom>::ChildrenTy
+typename ChildrenGetterTy<NodeTy, IsPostDom>::range
ChildrenGetterTy<NodeTy, IsPostDom>::get(const NodeRef &N) {
using OrderedNodeTy =
typename IDFCalculatorBase<NodeTy, IsPostDom>::OrderedNodeTy;
- auto Children = children<OrderedNodeTy>(N);
- return {Children.begin(), Children.end()};
+ return children<OrderedNodeTy>(N);
}
} // end of namespace IDFCalculatorDetail
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