[PATCH] D48935: [llvm-exegesis] Provide a way to handle memory instructions.

Guillaume Chatelet via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 30 00:01:19 PDT 2018


gchatelet added inline comments.


================
Comment at: tools/llvm-exegesis/lib/BenchmarkRunner.h:77
+        : UnalignedPtr(new char[kSize + kAlignment]),
+          AlignedPtr(UnalignedPtr + kAlignment -
+                     (reinterpret_cast<intptr_t>(UnalignedPtr) % kAlignment)) {}
----------------
courbet wrote:
> gchatelet wrote:
> > courbet wrote:
> > > gchatelet wrote:
> > > > Why not [aligned_alloc](https://en.cppreference.com/w/c/memory/aligned_alloc) ?
> > > > 
> > > the alignment of aligned_alloc has to be an alignment for a valid object. Some X86 instructions require 512 byte alignment, wich is not the alignment of any valid object. 
> > I don't understand why you can't use `aligned_alloc(1024, 1<<20);`?
> aligned_alloc is c++17...
I read C++11 on the link I provided.
https://en.cppreference.com/w/c/memory/aligned_alloc


Repository:
  rL LLVM

https://reviews.llvm.org/D48935





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