This change is discussed in D15392 and should allow us to effectively
revert:
http://llvm.org/viewvc/llvm-project?view=revision&revision=255261
if we canonicalize bitcasts ahead of extracts.
It should be safe to convert any pair of bitcasts into a single bitcast,
however, it was mentioned here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20110829/127089.html
that we're not allowed to bitcast from an x86_mmx to some other types, but I'm
not seeing any failures from that, and we have regression tests in CodeGen/X86
that appear to cover all of those cases.
Some day we'll get to remove that MMX wart from LLVM IR completely?
Differential Revision: http://reviews.llvm.org/D15468
llvm-svn: 255399
Sanjay Patel