Previously prefetch was only considered legal if sse was enabled, but it should be supported with 3dnow as well.
The prfchw flag now imply at least some form of prefetch without the write hint is available, either the sse or 3dnow version. This is true even if 3dnow and sse are explicitly disabled.
Similarly prefetchwt1 feature implies availability of prefetchw and the the prefetcht0/1/2/nta instructions. This way we can support _MM_HINT_ET0 using prefetchw and _MM_HINT_ET1 with prefetchwt1. And its assumed that if we have levels for the write hint we would have levels for the non-write hint, thus why we enable the sse prefetch instructions.
I believe this behavior is consistent with gcc. I've updated the prefetch.ll to test all of these combinations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321335 91177308-0d34-0410-b5e6-96231b3b80d8
`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.
See also the discussion in https://reviews.llvm.org/D35287
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309774 91177308-0d34-0410-b5e6-96231b3b80d8
- 'prefetch' intrinsics are only lowered when SSE is available. On non-X86
builds, 'generic' CPU is used and stops lowering any prefetch intrinsics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178046 91177308-0d34-0410-b5e6-96231b3b80d8
Craig Topper