API change for {BinaryOperator|CmpInst|CastInst}::create*() --> Create. Legacy interfaces will be in place for some time.  (Merge from use-diet branch.)

llvm-svn: 51200

using dyn_cast<> on already freed memory.

llvm-svn: 50618

Revert r50441.  The original code was correct.  Add some more comments so that I don't make the same mistake in the future.

llvm-svn: 50446

we were checking for it in the wrong order.  This caused a miscompilation because the
return slot optimization assumes that the call it is dealing with is NOT a memcpy.

llvm-svn: 50444

llvm-svn: 50442

and simplify code that was fallout from the separation of memcpyopt and gvn.

llvm-svn: 50034

GVN and into its own pass.

llvm-svn: 49419