`llc -march` is problematic because it only switches the target
architecture, but leaves the operating system unchanged. This
occasionally leads to indeterministic tests because the OS from
LLVM_DEFAULT_TARGET_TRIPLE is used.

However we can simply always use `llc -mtriple` instead. This changes
all the tests to do this to avoid people using -march when they copy and
paste parts of tests.

This patch:
- Removes -march if the .ll file already has a matching `target triple`
  directive or -mtriple argument.
- In all other cases changes -march=ppc32/-march=ppc64 to
  -mtriple=ppc32--/-mtriple=ppc64--

See also the discussion in https://reviews.llvm.org/D35287

llvm-svn: 309754

Currently we have a number of tests that fail with -verify-machineinstrs.
To detect this cases earlier we add the option to the testcases with the
exception of tests that will currently fail with this option. PR 27456 keeps
track of this failures.

No code review, as discussed with Hal Finkel.

llvm-svn: 277624

We don't need to reject all inline asm as using the counter register (most does
not). Only those that explicitly clobber the counter register need to prevent
the transformation.

llvm-svn: 182191