[all-commits] [llvm/llvm-project] c7750c: Add helper func to get first non-alloca position

[Sebastian Neubauer via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c7750c522e6d4fd2b7a67da59c38444f666308d2
      https://github.com/llvm/llvm-project/commit/c7750c522e6d4fd2b7a67da59c38444f666308d2
  Author: Sebastian Neubauer <Sebastian.Neubauer at amd.com>
  Date:   2022-09-09 (Fri, 09 Sep 2022)

  Changed paths:
    M llvm/include/llvm/IR/BasicBlock.h
    M llvm/include/llvm/IR/IRBuilder.h
    M llvm/lib/CodeGen/ShadowStackGCLowering.cpp
    M llvm/lib/IR/BasicBlock.cpp
    M llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

  Log Message:
  -----------
  Add helper func to get first non-alloca position

The LLVM performance tips suggest that allocas should be placed at the
beginning of the entry block. So far, llvm doesn’t provide any helper to
find that position.

Add BasicBlock::getFirstNonPHIOrDbgOrAlloca and IRBuilder::SetInsertPointPastAllocas(Function*)
that get an insert position after the (static) allocas at the start of a
function and use it in ShadowStackGCLowering.

Differential Revision: https://reviews.llvm.org/D132554