Fix overly pessimistic shortcut in post-RA MachineLICM

Post-RA LICM keeps three sets of registers: PhysRegDefs, PhysRegClobbers
and TermRegs.  When it sees a definition of R it adds all aliases of R
to the corresponding set, so that when it needs to test for membership
it only needs to test a single register, rather than worrying about
aliases there too.  E.g. the final candidate loop just has:

    unsigned Def = Candidates[i].Def;
    if (!PhysRegClobbers.test(Def) && ...) {

to test whether register Def is multiply defined.

However, there was also a shortcut in ProcessMI to make sure we didn't
add candidates if we already knew that they would fail the final test.
This shortcut was more pessimistic than the final one because it
checked whether _any alias_ of the defined register was multiply defined.
This is too conservative for targets that define register pairs.
E.g. on z, R0 and R1 are sometimes used as a pair, so there is a
128-bit register that aliases both R0 and R1.  If a loop used
R0 and R1 independently, and the definition of R0 came first,
we would be able to hoist the R0 assignment (because that used
the final test quoted above) but not the R1 assignment (because
that meant we had two definitions of the paired R0/R1 register
and would fail the shortcut in ProcessMI).

This patch just uses the same check for the ProcessMI shortcut as
we use in the final candidate loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188774 91177308-0d34-0410-b5e6-96231b3b80d8
Fix test typo and add usual "br %r14" test


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188775 91177308-0d34-0410-b5e6-96231b3b80d8
[mips][msa] Added insve



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188777 91177308-0d34-0410-b5e6-96231b3b80d8
memcmp is not a valid way to compare structs with padding in them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188778 91177308-0d34-0410-b5e6-96231b3b80d8
[SystemZ] Use SRST to optimize memchr

SystemZTargetLowering::emitStringWrapper() previously loaded the character
into R0 before the loop and made R0 live on entry.  I'd forgotten that
allocatable registers weren't allowed to be live across blocks at this stage,
and it confused LiveVariables enough to cause a miscompilation of f3 in
memchr-02.ll.

This patch instead loads R0 in the loop and leaves LICM to hoist it
after RA.  This is actually what I'd tried originally, but I went for
the manual optimisation after noticing that R0 often wasn't being hoisted.
This bug forced me to go back and look at why, now fixed as r188774.

We should also try to optimize null checks so that they test the CC result
of the SRST directly.  The select between null and the SRST GPR result could
then usually be deleted as dead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188779 91177308-0d34-0410-b5e6-96231b3b80d8
[SystemZ] Update README

We now use MVST, CLST and SRST for the obvious cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188781 91177308-0d34-0410-b5e6-96231b3b80d8
[mips][msa] Removed fcge, fcgt, fsge, fsgt

These instructions were present in a draft spec but were removed before
publication.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188782 91177308-0d34-0410-b5e6-96231b3b80d8