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author | Chris Lattner <sabre@nondot.org> | 2004-03-08 22:04:08 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2004-03-08 22:04:08 +0000 |
commit | 96ab5caf2db23939c21c36d9468fa6c95e23129d (patch) | |
tree | b03e785eb8b0154a88673947698e2dbf5c5c29c4 /lib/Analysis/ProfileInfo.cpp | |
parent | 7d84dda56044b9731aea613a26ff98c8ceb3b5f9 (diff) | |
download | llvm-96ab5caf2db23939c21c36d9468fa6c95e23129d.tar.gz llvm-96ab5caf2db23939c21c36d9468fa6c95e23129d.tar.bz2 llvm-96ab5caf2db23939c21c36d9468fa6c95e23129d.tar.xz |
Switch to using edge profiling information as the basic source of profile info
from using basic block counts.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12242 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/ProfileInfo.cpp')
-rw-r--r-- | lib/Analysis/ProfileInfo.cpp | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/lib/Analysis/ProfileInfo.cpp b/lib/Analysis/ProfileInfo.cpp index a96dc4f2fc..8cb1e00176 100644 --- a/lib/Analysis/ProfileInfo.cpp +++ b/lib/Analysis/ProfileInfo.cpp @@ -14,6 +14,8 @@ #include "llvm/Analysis/ProfileInfo.h" #include "llvm/Pass.h" +#include "llvm/Support/CFG.h" +#include <set> using namespace llvm; // Register the ProfileInfo interface, providing a nice name to refer to. @@ -23,6 +25,56 @@ namespace { ProfileInfo::~ProfileInfo() {} +unsigned ProfileInfo::getExecutionCount(BasicBlock *BB) const { + pred_iterator PI = pred_begin(BB), PE = pred_end(BB); + + // Are there zero predecessors of this block? + if (PI == PE) { + // If this is the entry block, look for the Null -> Entry edge. + if (BB == &BB->getParent()->front()) + return getEdgeWeight(0, BB); + else + return 0; // Otherwise, this is a dead block. + } + + // Otherwise, if there are predecessors, the execution count of this block is + // the sum of the edge frequencies from the incoming edges. Note that if + // there are multiple edges from a predecessor to this block that we don't + // want to count its weight multiple times. For this reason, we keep track of + // the predecessors we've seen and only count them if we haven't run into them + // yet. + // + // We don't want to create an std::set unless we are dealing with a block that + // has a LARGE number of in-edges. Handle the common case of having only a + // few in-edges with special code. + // + BasicBlock *FirstPred = *PI; + unsigned Count = getEdgeWeight(FirstPred, BB); + ++PI; + if (PI == PE) return Count; // Quick exit for single predecessor blocks + + BasicBlock *SecondPred = *PI; + if (SecondPred != FirstPred) Count += getEdgeWeight(SecondPred, BB); + ++PI; + if (PI == PE) return Count; // Quick exit for two predecessor blocks + + BasicBlock *ThirdPred = *PI; + if (ThirdPred != FirstPred && ThirdPred != SecondPred) + Count += getEdgeWeight(ThirdPred, BB); + ++PI; + if (PI == PE) return Count; // Quick exit for three predecessor blocks + + std::set<BasicBlock*> ProcessedPreds; + ProcessedPreds.insert(FirstPred); + ProcessedPreds.insert(SecondPred); + ProcessedPreds.insert(ThirdPred); + for (; PI != PE; ++PI) + if (ProcessedPreds.insert(*PI).second) + Count += getEdgeWeight(*PI, BB); + return Count; +} + + //===----------------------------------------------------------------------===// // NoProfile ProfileInfo implementation |