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d1d1d7910e
Convert the previous introduced is-a relationship between the LVICache and LVIImple clases into a has-a relationship and hide all the implementation details of the cache from the lazy query layer. The only slightly concerning change here is removing the addition of a queried block into the SeenBlock set in LVIImpl::getBlockValue. As far as I can tell, this was effectively dead code. I think it *used* to be the case that getCachedValueInfo wasn't const and might end up inserting elements in the cache during lookup. That's no longer true and hasn't been for a while. I did fixup the const usage to make that more obvious. llvm-svn: 281272
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))
//===---------------------------------------------------------------------===//