[PATCH][X86] Factor out new helper getPSHUFB
anemet at apple.com
Mon Mar 24 22:52:57 PDT 2014
I found three implementations of this. This splits it out into a new function
and uses it from the three places.
My plan is to add a fourth use when lowering a vector_shuffle:v16i16.
Compared the assembly output of test/CodeGen/X86 before and after.
The only change is due to how the first PSHUFB was generated in
LowerVECTOR_SHUFFLEv8i16. If the shuffle mask specified undef (i.e. -1), the
old implementation would write -1 * 2 and -1 * 2 + 1 (254 and 255) in the
control mask. Now we write 0x80. These are of course interchangeable since
bit 7 decides if a constant zero is written in the result byte. The other
instances of this code used 0x80 consistently.
Related to <rdar://problem/16167303>
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 6564 bytes
Desc: not available
More information about the llvm-commits