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9fd063832c
Summary: Instead of using the workaround of suppressing the entire index for modules that call inline asm that may reference locals, use the NoRename flag on the summary for any locals in the llvm.used set, and add a reference edge from any functions containing inline asm. This avoids issues from having no summaries despite the module defining global values, which was preventing more aggressive index-based optimization. It will be followed by a subsequent patch to make a similar fix for local references in module level asm (to fix PR30610). Reviewers: mehdi_amini Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D26121 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285513 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))
//===---------------------------------------------------------------------===//