Jakob Stoklund Olesen 026ac3ada5 Revert test polarity to match comment and desired outcome. Remove undeserved bonus.
A GEP with all constant indices is already considered free by
analyzeBasicBlock(), so don't give it an extra bonus in
CountCodeReductionForAlloca().

This patch should remove a small positive bias toward inlining functions with
variable-index GEPs, and remove a smaller negative bias from functions with
all-constant index GEPs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94591 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-26 21:31:35 +00:00
..
2009-12-04 04:15:36 +00:00

Analysis Opportunities:

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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.

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