bdf added a comment. In D88363#2319157 <https://reviews.llvm.org/D88363#2319157>, @jmorse wrote:
> In D88363#2317241 <https://reviews.llvm.org/D88363#2317241>, @Mordante wrote: > >> Can you explain the kind of issues you're having? > > At the shallowest level, our -O1 produces different IR and fails the test, > which is more or less our problem; however my understanding is that tests in > the LLVM project / subprojects should aim to test as little amount of code as > possible. Relying on all of -O1 makes it a brittle test -- changes to any > optimisation pass enabled in -O1 could cause this test to fail spuriously. > > Instead, I believe the test should be in two parts: > > - One checking clang produces the correct /unoptimised/ IR output > - One or more checking that the consuming IR passes do-the-right-thing As I see, the intent of the test is not so much to verify a certain expected output, but more to verify that two styles of likelihood hints in C code produce the same code structure and branch weights. Theses styles are likely/unlikely-annotations, and use of __builtin_expect in the if condition. But the processing of these two is quite different: - for likely/unlikely annotations, branch weights are added immediately in the initial CodeGen - __builtin_expect is first translated straightforward to an expect intrinsic, then processed by a later lower-expect pass To make the test less brittle, would it be possible to explicitly select only the optimization passes that are needed? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D88363/new/ https://reviews.llvm.org/D88363 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
