#5567: LLVM: Improve alias analysis / performance -------------------------------------+------------------------------------- Reporter: dterei | Owner: dterei Type: task | Status: new Priority: normal | Milestone: Component: Compiler (LLVM) | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dobenour): Have the LLVM devs been asked about this? I think that GHC's use of CPS (and its non-use of the C stack) might be one of the problems. LLVM is designed for C-style code and its optimizations might not fire on the IR that GHC generates. I can think of a solution, but it would involve significant changes, both to the compiler and the RTS. The idea is to do a CPS => SSA transform and then lower to LLVM IR from the SSA form. The Haskell stack would become the C stack, with stack switching handled by the assembler code in `StgRun`. LLVM's GC support would be used to generate stack maps to be read by the RTS for GC purposes. Fortunately, I believe that these tasks are relatively independent. I suspect (from what others have said) that an equivalent of LLVM's `mem2reg` for the STG stack is what is needed. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/5567#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler