bench: Avoid deprecated use of volatile += #24372

1. 
   MarcoFalke commented at 4:47 pm on February 17, 2022: member

   Deprecated in C++20 according to https://eel.is/c++draft/expr.ass#6 .

   0bench/examples.cpp:16:13: warning: compound assignment with ‘volatile’-qualified left operand is deprecated [-Wvolatile]
   1   16 |         sum += sin(d);
   2      |         ~~~~^~~~~~~~~
   

   While C++20 is currently unsupported, I don’t see any downside to a minor fixup to an example benchmark. This will also make a hypothetical C++20 patch smaller.

2. bench: Avoid deprecated use of volatile += 9999f891d1
3. 
   MarcoFalke commented at 4:49 pm on February 17, 2022: member

   Can be tested with #24169 or by looking at the CI output: https://cirrus-ci.com/task/6478320643604480?logs=ci#L3123
4. 
   MarcoFalke commented at 5:05 pm on February 17, 2022: member

   On my system this doesn’t change the binary with g++ -O2, but it does with clang++ -O2.
5. DrahtBot added the label Tests on Feb 17, 2022
6. RandyMcMillan referenced this in commit 786a5e6ba4 on Feb 18, 2022
7. fanquake approved
8. 
   fanquake commented at 11:29 am on February 23, 2022: member

   ACK 9999f891d1c9093e552492cf8ccc3168370c7a39
9. fanquake merged this on Feb 23, 2022
10. fanquake closed this on Feb 23, 2022

    ---

11. MarcoFalke deleted the branch on Feb 23, 2022
12. sidhujag referenced this in commit 4592c3f1bb on Feb 23, 2022
13. PastaPastaPasta referenced this in commit 5e4db4ea26 on Apr 7, 2022
14. PastaPastaPasta referenced this in commit 7e598dd632 on Apr 11, 2022
15. DrahtBot locked this on Feb 23, 2023

Contributors
MarcoFalke fanquake

Labels
Tests