Dan Gohman 6ce9d8b0ed Move all the logic for function attributes and call attributes out of the
AliasAnalysis base class and into BasicAliasAnalyais. This avoids confusion
about where such logic is happening when there are other AliasAnalysis
implementations present.

Move the logic for translating two-callsite getModRefInfo queries into
other AliasAnalysis queries out of BasicAliasAnalysis and into the
AliasAnalysis base class, as it is useful for other AliasAnalysis
implementations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110421 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 01:25:49 +00:00
..
2010-08-06 00:23:35 +00:00
2010-07-28 10:57:28 +00:00
2010-08-03 02:38:20 +00:00
2010-08-06 00:23:35 +00:00
2010-08-06 00:23:35 +00:00
2010-08-06 00:23:35 +00:00
2010-08-06 00:23:35 +00:00

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))

//===---------------------------------------------------------------------===//