-debug-pass is not specified, as the string is only used when dumping pass
information. There is a big cost of determining the name in
ReginBase<Tr>:getNameStr() if the region's entry or exit block doesn't have a
name. This is the case for the Release build, as names are not preserved by the
front-end.
RegionPass is mainly used by Polly, resulting in long compile time for one file
of a customer application with the Release build (1m24s) vs Release+Asserts
build (10s) when Polly is used. With this change, the compile time with the
Release build went down to 8s.
Patch by Sanjin Sijaric <ssijaric@codeaurora.org>!
Phabricator: http://reviews.llvm.org/D8076
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231485 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))
//===---------------------------------------------------------------------===//
3ad549487e