Summary:
Runtime unrolling of loops needs to emit an expression to compute the
loop's runtime trip-count. Avoid runtime unrolling if this computation
will be expensive.
Depends on D8993.
Reviewers: atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8994
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234846 91177308-0d34-0410-b5e6-96231b3b80d8
It's firstly committed at r231630, and reverted at r231635.
Function pass InstructionSimplifier is inserted as barrier to
make sure loop unroll pass won't affect on LICM pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232011 91177308-0d34-0410-b5e6-96231b3b80d8
Runtime unrollng will introduce a runtime check in loop prologue.
If the unrolled loop is a inner loop, then the proglogue will be inside
the outer loop. LICM pass can help to promote the runtime check out if
the checked value is loop invariant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231630 91177308-0d34-0410-b5e6-96231b3b80d8
