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Graham Hunter
ea3b91f5a6
* Adds a TypeSize struct to represent the known minimum size of a type along with a flag to indicate that the runtime size is a integer multiple of that size * Converts existing size query functions from Type.h and DataLayout.h to return a TypeSize result * Adds convenience methods (including a transparent conversion operator to uint64_t) so that most existing code 'just works' as if the return values were still scalars. * Uses the new size queries along with ElementCount to ensure that all supported instructions used with scalable vectors can be constructed in IR. Reviewers: hfinkel, lattner, rkruppe, greened, rovka, rengolin, sdesmalen Reviewed By: rovka, sdesmalen Differential Revision: https://reviews.llvm.org/D53137 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374042 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))
//===---------------------------------------------------------------------===//