Change the basic block weight calculation algorithm to use max instead of voting.
Summary: Now that we have more precise debug info, we should change back to use maximum to get basic block weight.
Reviewers: dnovillo
Subscribers: andreadb, llvm-commits
Differential Revision: https://reviews.llvm.org/D24788
llvm-svn: 282084
diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index 0594063..dd91896 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -513,24 +513,16 @@
/// \returns the weight for \p BB.
ErrorOr<uint64_t>
SampleProfileLoader::getBlockWeight(const BasicBlock *BB) const {
- DenseMap<uint64_t, uint64_t> CM;
+ uint64_t Max = 0;
+ bool HasWeight = false;
for (auto &I : BB->getInstList()) {
const ErrorOr<uint64_t> &R = getInstWeight(I);
- if (R)
- CM[R.get()]++;
- }
- if (CM.size() == 0)
- return std::error_code();
- uint64_t W = 0, C = 0;
- for (const auto &C_W : CM) {
- if (C_W.second == W) {
- C = std::max(C, C_W.first);
- } else if (C_W.second > W) {
- C = C_W.first;
- W = C_W.second;
+ if (R) {
+ Max = std::max(Max, R.get());
+ HasWeight = true;
}
}
- return C;
+ return HasWeight ? ErrorOr<uint64_t>(Max) : std::error_code();
}
/// \brief Compute and store the weights of every basic block.