GSoC 2023 Week 15 and 16

This blog post is related to my GSoC 2023 Project.

I landed these patches in week 15:

• [InstCombine] Remove unneeded isa<PHINode> check in foldOpIntoPhi

• [InstCombine] Test case for D155718

• [NFC][TLI] Replace std::lower_bound call in getLibFunc with DenseMap lookup

• [NFC][ValueTracking] Remove calls to computeKnownBits for non-intrinsic CallInsts in isKnownNonZeroFromOperator

In week 16, I mostly worked on finishing up the tests for the InferAlignment pass, in D158530. These have just been taking their sweet time as I’ve been working on getting a reduced set of test cases, which covers the functionality without being excessively verbose like before. I also rearranged the patches so that the tests come first, then the InferAlignment pass implementation, then the changes to InstCombine, and finally enabling the pass by default. This involves the use of a cl::opt with a default value. Thus, the current order of patches is:

• [InferAlignment] Create tests for InferAlignment pass

• [InferAlignment] Implement InferAlignmentPass

• [InstCombine] Add a cl::opt to control calls to getOrEnforceKnownAlignment in LoadInst and StoreInst

• [InferAlignment] Enable InferAlignment pass by default