[PATCH] D13364: [x86] PR24562: fix incorrect folding of X86ISD::PSHUFB nodes that have a mask of all indices with the most significant bit set.

[Andrea Di Biagio via llvm-commits]

andreadb added a comment.

In http://reviews.llvm.org/D13364#260609, @RKSimon wrote:

> What about asserting that the Index is Zero/Undef or a valid index? This might be going too far but the 'undef == (index < 0)' pattern is something that is very common in the shuffle code and I think we should be doing more to sanitize these values,


Right, I will do it. I understand your concern (and I have similar concerns :-) ).
As you said, "this may be going to far" but it definitely won't hurt to have an extra assert in the code to validate a precondition.
I will update the patch.

Thanks Simon!


http://reviews.llvm.org/D13364