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Summary: Add a `cleanupendpad` instruction, used to mark exceptional exits out of cleanups (for languages/targets that can abort a cleanup with another exception). The `cleanupendpad` instruction is similar to the `catchendpad` instruction in that it is an EH pad which is the target of unwind edges in the handler and which itself has an unwind edge to the next EH action. The `cleanupendpad` instruction, similar to `cleanupret` has a `cleanuppad` argument indicating which cleanup it exits. The unwind successors of a `cleanuppad`'s `cleanupendpad`s must agree with each other and with its `cleanupret`s. Update WinEHPrepare (and docs/tests) to accomodate `cleanupendpad`. Reviewers: rnk, andrew.w.kaylor, majnemer Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D12433 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246751 91177308-0d34-0410-b5e6-96231b3b80d8
Analysis Opportunities:
//===---------------------------------------------------------------------===//
In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
ScalarEvolution expression for %r is this:
{1,+,3,+,2}<loop>
Outside the loop, this could be evaluated simply as (%n * %n), however
ScalarEvolution currently evaluates it as
(-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))
In addition to being much more complicated, it involves i65 arithmetic,
which is very inefficient when expanded into code.
//===---------------------------------------------------------------------===//
In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll,
ScalarEvolution is forming this expression:
((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32)))
This could be folded to
(-1 * (trunc i64 undef to i32))
//===---------------------------------------------------------------------===//