Simon Peyton Jones pushed to branch wip/T27724 at Glasgow Haskell Compiler / GHC Commits: dc55d4ce by Simon Peyton Jones at 2026-09-15T17:34:57+01:00 Redesign the noinline magic Main idea: * When simplifying `noinline (f e1 e2)`, switch off inlining when simplifying `f` * Mechanism: see `simplOutId`, the `noinlineIdKey` case * If we see `noinline (f e1) e2`, the simplifier moves the `e2` inside; see the `splitContArgs` call. This is important so you can write `noinliine f e1 e2` and have it mean the same as `noinline (f e1 e2)`. * Now `f` sees all its arguments, henc: * Fixes #27724 * Fixes #23911 * Also fixes #27803 where we were not respecting `noinline` if the RHS was trivial See Note [noinlineId magic] for lots of specifics. It's surprisingly tricky! For some reason a couple of perf tests allocate 1.2% less at compile time,n namely T29872 and T8095. Geom mean decease of 0.1% Metric Decrease: T9872d - - - - - 32 changed files: - + changelog.d/T27724 - compiler/GHC/Builtin/WiredIn/Ids.hs - compiler/GHC/Builtin/WiredIn/Prim.hs - compiler/GHC/Core/Opt/SetLevels.hs - compiler/GHC/Core/Opt/Simplify/Env.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/Simplify/Utils.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/Type.hs - compiler/GHC/CoreToIface.hs - compiler/GHC/CoreToStg/Prep.hs - compiler/GHC/Driver/Config/Core/Opt/Simplify.hs - compiler/GHC/HsToCore.hs - compiler/GHC/HsToCore/Expr.hs - compiler/GHC/Tc/Instance/Class.hs - compiler/GHC/Tc/Types/Origin.hs - libraries/ghc-internal/src/GHC/Internal/Magic.hs - testsuite/tests/corelint/LintEtaExpand.hs - + testsuite/tests/dmdanal/should_compile/T23911.hs - + testsuite/tests/dmdanal/should_compile/T23911.stderr - testsuite/tests/dmdanal/should_compile/all.T - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout - testsuite/tests/interface-stability/ghc-prim-exports.stdout - testsuite/tests/simplCore/should_compile/T18995.stderr - + testsuite/tests/simplCore/should_compile/T27724a.hs - + testsuite/tests/simplCore/should_compile/T27724a.stderr - + testsuite/tests/simplCore/should_compile/T27803.hs - + testsuite/tests/simplCore/should_compile/T27803.stderr - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_fail/T17940.stderr - utils/genprimopcode/Main.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/dc55d4ce900445241c228693fe3bc1a6... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/dc55d4ce900445241c228693fe3bc1a6... You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help