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cfc42962c8
The doFinalization method checks that the LoopToAliasSetMap is empty. LICM populates that map as it runs through the loop nest, deleting the entries for child loops as it goes. However, if a child loop is deleted by another pass (e.g. unrolling) then the loop will never be deleted from the map because LICM walks the loop nest to find entries it can delete. The fix is to delete the loop from the map and free the alias set when the loop is deleted from the loop nest. Differential Revision: http://reviews.llvm.org/D5305 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218387 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))
//===---------------------------------------------------------------------===//