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Sanjay Patel
aeeabb506a
This just identifies the intrinsics as candidates for vectorization. It does not mean we will attempt to vectorize under normal conditions (the test file is forcing vectorization). The cost model must be fixed to show that the transform is profitable in general. Allowing vectorization with these intrinsics is required to avoid potential regressions from canonicalizing to the intrinsics from generic IR: https://bugs.llvm.org/show_bug.cgi?id=37417 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346661 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))
//===---------------------------------------------------------------------===//