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The 'ord' and 'uno' predicates have a logic operation for NAN built into their definitions: FCMP_ORD = 7, ///< 0 1 1 1 True if ordered (no nans) FCMP_UNO = 8, ///< 1 0 0 0 True if unordered: isnan(X) | isnan(Y) So we can simplify patterns like this: (fcmp ord (known NNAN), X) && (fcmp ord X, Y) --> fcmp ord X, Y (fcmp uno (known NNAN), X) || (fcmp uno X, Y) --> fcmp uno X, Y It might be better to split this into (X uno 0) | (Y uno 0) as a canonicalization, but that would be another patch. Differential Revision: https://reviews.llvm.org/D40130 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318627 91177308-0d34-0410-b5e6-96231b3b80d8
Analysis Opportunities:
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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))
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