[PATCH] D139882: [NFC][MC] `MCInst`: `Operands` small size optimization: store 16, not 8, inline `MCOperand`

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: RKSimon, craig.topper, grosbach.
lebedev.ri added a project: LLVM.
Herald added subscribers: StephenFan, mstojanovic.
Herald added a project: All.
lebedev.ri requested review of this revision.
Herald added a subscriber: courbet.

This improves the torture test of

  ./bin/llvm-exegesis -mcpu=znver3 -mode=inverse_throughput --opcode-index=-1 --benchmarks-file=/dev/null --dump-object-to-disk=0 --measurements-print-progress --skip-measurements

from 2m17s to 2min14s, and has the following effect on memory:

  heaptrack stats:
  allocations:100809844 -> 77342110 (-23%)
  leaked allocations: 1128
  temporary allocations:  24911145  -> 1576268  (-93.7%) !!!

... at the cost of slightly higher peak RSS and peak heap memory consumption:

I'm not sure who is the code owner of this component.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D139882

Files:
  llvm/include/llvm/MC/MCInst.h


Index: llvm/include/llvm/MC/MCInst.h
===================================================================
--- llvm/include/llvm/MC/MCInst.h
+++ llvm/include/llvm/MC/MCInst.h
@@ -189,7 +189,7 @@
   unsigned Flags = 0;
 
   SMLoc Loc;
-  SmallVector<MCOperand, 8> Operands;
+  SmallVector<MCOperand, 16> Operands;
 
 public:
   MCInst() = default;


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