ffe8720aa0
This header is very large (3M Lines once expended) and was included in location where dwarf-specific information were not needed. More specifically, this commit suppresses the dependencies on llvm/BinaryFormat/Dwarf.h in two headers: llvm/IR/IRBuilder.h and llvm/IR/DebugInfoMetadata.h. As these headers (esp. the former) are widely used, this has a decent impact on number of preprocessed lines generated during compilation of LLVM, as showcased below. This is achieved by moving some definitions back to the .cpp file, no performance impact implied[0]. As a consequence of that patch, downstream user may need to manually some extra files: llvm/IR/IRBuilder.h no longer includes llvm/BinaryFormat/Dwarf.h llvm/IR/DebugInfoMetadata.h no longer includes llvm/BinaryFormat/Dwarf.h In some situations, codes maybe relying on the fact that llvm/BinaryFormat/Dwarf.h was including llvm/ADT/Triple.h, this hidden dependency now needs to be explicit. $ clang++ -E -Iinclude -I../llvm/include ../llvm/lib/Transforms/Scalar/*.cpp -std=c++14 -fno-rtti -fno-exceptions | wc -l after: 10978519 before: 11245451 Related Discourse thread: https://llvm.discourse.group/t/include-what-you-use-include-cleanup [0] https://llvm-compile-time-tracker.com/compare.php?from=fa7145dfbf94cb93b1c3e610582c495cb806569b&to=995d3e326ee1d9489145e20762c65465a9caeab4&stat=instructions Differential Revision: https://reviews.llvm.org/D118781
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))
//===---------------------------------------------------------------------===//