[llvm-commits] [llvm] r169791 - in /llvm/trunk: include/llvm/Target/ lib/CodeGen/SelectionDAG/ lib/Target/ARM/ lib/Target/Mips/ lib/Target/X86/ test/CodeGen/ARM/ test/CodeGen/X86/

[Eli Friedman]

On Mon, Dec 10, 2012 at 3:21 PM, Evan Cheng <evan.cheng at apple.com> wrote:
> Author: evancheng
> Date: Mon Dec 10 17:21:26 2012
> New Revision: 169791
>
> URL: http://llvm.org/viewvc/llvm-project?rev=169791&view=rev
> Log:
> Some enhancements for memcpy / memset inline expansion.
> 1. Teach it to use overlapping unaligned load / store to copy / set the trailing
>    bytes. e.g. On 86, use two pairs of movups / movaps for 17 - 31 byte copies.
> 2. Use f64 for memcpy / memset on targets where i64 is not legal but f64 is. e.g.
>    x86 and ARM.

This won't work correctly on x86 if we don't have SSE2.  (Loading an
f64 into an x87 register is a lossy operation.)

-Eli