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This patch fixes a crash caused by an incorrect folding of an ordered comparison between a packed floating point vector and a splat vector of NaN. An ordered comparison between a vector and a constant vector of NaN, should always be folded into a constant vector where each element is i1 false. Since revision 266175, SimplifyFCmpInst folds the ordered fcmp into a scalar 'false'. Later on, this would cause an assertion failure, since the value type of the folded value doesn't match the expected value type of the uses of the original instruction: "Assertion failed: New->getType() == getType() && "replaceAllUses of value with new value of different type!". This patch fixes the issue and adds a test case to the already existing test InstSimplify/floating-point-compares.ll. Differential Revision: https://reviews.llvm.org/D24143 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280488 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))
//===---------------------------------------------------------------------===//