[cfe-commits] [PATCH] PR12094: set alignment of memory builtins

[Chris Lattner]

On Mar 2, 2012, at 3:57 AM, Jay Foad wrote:

> http://llvm.org/bugs/show_bug.cgi?id=12094
> 
> The attached patch:
> 
> - Makes CGBuiltin.cpp's helper function GetPointeeAlignment into a
> proper member of CodeGenFunction and splits it into two:
> -- GetPointeeAlignment, which returns alignment as an unsigned, and
> -- GetPointeeAlignmentValue, which wraps the result in an llvm::Value
> for the convenience of generating ARM NEON intrinsics.

Looks great to me, please commit Jay.  Thanks for tackling this!

-Chris

> 
> - Uses GetPointeeAlignment to set a sensible alignment on all memory
> intrinsics (memcpy, memset etc.) instead of the conservative default
> of 1.
> 
> Tested with "make check-all". Unfortunately I can only test on x86_64,
> where alignment doesn't make much difference. Can anyone test it on
> what GCC would call a STRICT_ALIGNMENT target for me?
> 
> I also tried compiling sqlite3.c (from test-suite) with clang -O2,
> before and after my changes. The only differences were a handful of
> calls to memcpy replaced with "rep;movsq", which seems good.
> 
> Thanks,
> Jay.
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