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A comment on Benchmarking C++ Allocators. Parent comment

Re:Benchmarking C++ Allocators by jepler on Monday April 27, 2020 @08:20PM (#23001894)
https://godbolt.org/z/z-92qR

Interestingly, the compiler emits no call to malloc, even. What!?

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Re:Benchmarking C++ Allocators by steerablesafe on Tuesday April 28, 2020 @05:01AM (#23005107)
With -fno-builtin. It's still "cheating" as b is local.

https://godbolt.org/z/U5VGxt

Without cheating:

https://godbolt.org/z/rzcXg2

It doesn't optimize the two stores to b away.

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Re:Benchmarking C++ Allocators by gpderetta on Monday April 27, 2020 @08:41PM (#23002020)
The compiler knows the semantics of malloc. Malloc as it appear in the source code doesn't even need to map 1:1 to calls to the library function, the compiler can remove and coalesce calls at will.
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