Includes adding more general support for the pattern: VZEXT_MOVL(VZEXT_LOAD(ptr)) -> VZEXT_LOAD(ptr)
This has unearthed a couple of latent poor codegen issues (MINSS/MAXSS scalar load folding and MOVDDUP/BROADCAST load folding patterns), which will be fixed shortly.
Its also reduced a couple of tests so that they no longer reach the instruction threshold necessary to be combined to PSHUFB (see PR26183).
llvm-svn: 279646
We don't really support non-constant shuffle masks, but these tests are for cases where BUILD_VECTOR is made up from vector extracts (as well as undef/zero scalars).
llvm-svn: 265045
Simon Pilgrim