[llvm] 4ce6542 - [memprof] Use const ref for IndexedRecord (#94114)

[via llvm-commits]

Author: Kazu Hirata
Date: 2024-06-02T13:30:32-07:00
New Revision: 4ce65423be0ba1d90c11b6a79981d6314e1cf36d

URL: https://github.com/llvm/llvm-project/commit/4ce65423be0ba1d90c11b6a79981d6314e1cf36d
DIFF: https://github.com/llvm/llvm-project/commit/4ce65423be0ba1d90c11b6a79981d6314e1cf36d.diff

LOG: [memprof] Use const ref for IndexedRecord (#94114)

The type of *Iter here is "const IndexedMemProfRecord &" as defined in
RecordLookupTrait.  Assigning *Iter to a variable of type
"const IndexedMemProfRecord &" avoids a copy, reducing the cycle and
instruction counts by 1.8% and 0.2%, respectively, with
"llvm-profdata show" modified to deserialize all MemProfRecords.

Note that RecordLookupTrait has an internal copy of
IndexedMemProfRecord, so we don't have to worry about a dangling
reference to a temporary.

Added: 
    

Modified: 
    llvm/lib/ProfileData/InstrProfReader.cpp

Removed: 
    


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diff  --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
index 1e66716294689..8298d3d372951 100644
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -1613,7 +1613,7 @@ IndexedMemProfReader::getMemProfRecord(const uint64_t FuncNameHash) const {
         instrprof_error::unknown_function,
         "memprof record not found for function hash " + Twine(FuncNameHash));
 
-  const memprof::IndexedMemProfRecord IndexedRecord = *Iter;
+  const memprof::IndexedMemProfRecord &IndexedRecord = *Iter;
   switch (Version) {
   case memprof::Version0:
   case memprof::Version1: