... under the EXPENSIVE_CHECKS build, this fails the assert in the LegacyPM
that verifies whether a pass really did leave the IR alone when it reports no
changes back from its return status.
This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.
I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
recompiles touches affected_files header
342380 95 3604 llvm/include/llvm/ADT/STLExtras.h
314730 234 1345 llvm/include/llvm/InitializePasses.h
307036 118 2602 llvm/include/llvm/ADT/APInt.h
213049 59 3611 llvm/include/llvm/Support/MathExtras.h
170422 47 3626 llvm/include/llvm/Support/Compiler.h
162225 45 3605 llvm/include/llvm/ADT/Optional.h
158319 63 2513 llvm/include/llvm/ADT/Triple.h
140322 39 3598 llvm/include/llvm/ADT/StringRef.h
137647 59 2333 llvm/include/llvm/Support/Error.h
131619 73 1803 llvm/include/llvm/Support/FileSystem.h
Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.
Reviewers: bkramer, asbirlea, bollu, jdoerfert
Differential Revision: https://reviews.llvm.org/D70211
This patch adds a new IRTransformations directory to llvm/examples/. This is
intended to serve as a new home for example transformations/analysis
code used by various tutorials.
If LLVM_BUILD_EXAMPLES is enabled, the ExamplesIRTransforms library is
linked into the opt binary and the example passes become available.
To start off with, it contains the CFG simplifications used in the IR
part of the 'Getting Started With LLVM: Basics' tutorial at the US LLVM
Developers Meeting 2019.
Reviewers: paquette, jfb, meikeb, lhames, kbarton
Reviewed By: paquette
Differential Revision: https://reviews.llvm.org/D69416
Jon Roelofs