[llvm] [SimplifyCFG] Use hash map to continue hoisting the common instructions (PR #78615)
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Wed Mar 20 08:35:48 PDT 2024
================
@@ -1635,87 +1675,149 @@ bool SimplifyCFGOpt::hoistCommonCodeFromSuccessors(BasicBlock *BB,
// many instructions we skip, serving as a compilation time control as well as
// preventing excessive increase of life ranges.
unsigned NumSkipped = 0;
- // If we find an unreachable instruction at the beginning of a basic block, we
- // can still hoist instructions from the rest of the basic blocks.
- if (SuccIterPairs.size() > 2) {
- erase_if(SuccIterPairs,
- [](const auto &Pair) { return isa<UnreachableInst>(Pair.first); });
- if (SuccIterPairs.size() < 2)
- return false;
- }
bool Changed = false;
+ auto *SuccIterPairBegin = SuccIterPairs.begin();
+ ++SuccIterPairBegin;
+ auto BBItrPair = *SuccIterPairBegin++;
+ auto OtherSuccIterPairRange =
+ iterator_range(SuccIterPairBegin, SuccIterPairs.end());
+
+ DenseMap<llvm::hash_code, SmallVector<Instruction *, 2>> OtherSuccessorsHash;
+ DenseMap<Instruction *, unsigned> InstToSkipFlag;
+ unsigned skipFlag = 0;
+ Instruction *I = nullptr;
+ do {
+ I = &*BBItrPair.first;
+ auto HashValue = getHash(I);
+ skipFlag |= skippedInstrFlags(I);
+ // For the first successor we created hashmap for, put all instructions
+ // in the hashmap execept for the ones that have the same hash as some
----------------
nikic wrote:
```suggestion
// in the hashmap except for the ones that have the same hash as some
```
https://github.com/llvm/llvm-project/pull/78615
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