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1ab487fdc7
when all are being preserved. We want to short-circuit this for a couple of reasons. One, I don't really want passes to grow a dependency on actually receiving their invalidate call when they've been preserved. I'm thinking about removing this entirely. But more importantly, preserving everything is likely to be the common case in a lot of scenarios, and it would be really good to bypass all of the invalidation and preservation machinery there. Avoiding calling N opaque functions to try to invalidate things that are by definition still valid seems important. =] This wasn't really inpsired by much other than seeing the spam in the logging for analyses, but it seems better ot get it checked in rather than forgetting about it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225163 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))
//===---------------------------------------------------------------------===//