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Tom Stellard
6e4b75df4f
Summary: In preparation for changing GlobalsAA to stop assuming that intrinsics can't read arbitrary globals, we need to make sure GlobalsAA is querying function attributes rather than relying on this assumption. This patch was inspired by: http://reviews.llvm.org/D20206 Reviewers: jmolloy, hfinkel Subscribers: eli.friedman, llvm-commits Differential Revision: https://reviews.llvm.org/D21318 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275433 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))
//===---------------------------------------------------------------------===//