[llvm-commits] [llvm] r51019 - in /llvm/trunk: lib/Target/X86/README-SSE.txt lib/Target/X86/X86InstrInfo.td test/CodeGen/X86/vec_set-H.ll

[Chris Lattner]

On May 13, 2008, at 9:43 AM, Evan Cheng wrote:

>
> On May 13, 2008, at 1:22 AM, Duncan Sands wrote:
>
>> Hi Evan,
>>
>>> On x86, it's safe to treat i32 load anyext as a normal i32 load.
>>> Ditto for i8 anyext load to i16.
>>
>> if this was loading the last two bytes in a page, then now it will be
>> loading two bytes from the next page, which could trap.  Similarly,  
>> if
>
> I'm pretty certain that's not possible on x86.

Checking that the i8 is known to have 16 bit alignment should be  
sufficient to prevent this.

-Chris