revisit #47137: avoid round-trip of locally-cached inferred source

Built on top of #51958, with the improved performance of `cfg_simplify!`,
let's give another try on #47137. Tha aim is to retain
locally cached inferred source as `IRCode`, eliminating the need for the
inlining algorithm to round-trip it through `CodeInfo` representation.

base/compiler/abstractinterpretation.jl

@@ -1193,6 +1193,7 @@ function const_prop_call(interp::AbstractInterpreter,
  add_remark!(interp, sv, "[constprop] Could not retrieve the source")
  return nothing # this is probably a bad generated function (unsound), but just ignore it
  end
+ inf_result.must_be_codeinf = false
  frame.parent = sv
  if !typeinf(interp, frame)
  add_remark!(interp, sv, "[constprop] Fresh constant inference hit a cycle")

base/compiler/optimize.jl

@@ -95,6 +95,7 @@ function inlining_policy(interp::AbstractInterpreter,
  return nothing
  end
  elseif isa(src, IRCode)
+ # n.b. the inlineability was computed within `finish!`
  return src
  elseif isa(src, SemiConcreteResult)
  if is_declared_noinline(mi.def::Method)
@@ -196,10 +197,9 @@ include("compiler/ssair/passes.jl")
 include("compiler/ssair/irinterp.jl")
 
 function ir_to_codeinf!(opt::OptimizationState)
- (; linfo, src) = opt
- src = ir_to_codeinf!(src, opt.ir::IRCode)
+ src = ir_to_codeinf!(opt.src, opt.ir::IRCode)
  opt.ir = nothing
- validate_code_in_debug_mode(linfo, src, "optimized")
+ validate_code_in_debug_mode(opt.linfo, src, "optimized")
  return src
 end
 

base/compiler/typeinfer.jl

@@ -227,8 +227,14 @@ function finish!(interp::AbstractInterpreter, caller::InferenceState)
  store_backedges(result, caller.stmt_edges[1])
  end
  opt = result.src
- if opt isa OptimizationState && result.must_be_codeinf
- result.src = opt = ir_to_codeinf!(opt)
+ if opt isa OptimizationState
+ if result.must_be_codeinf
+ result.src = opt = ir_to_codeinf!(opt)
+ else is_inlineable(opt.src) || is_stmt_inline(get_curr_ssaflag(caller.parent::InferenceState))
+ # TODO Delay `cfg_simplify!` until when needed?
+ # Currently it results in segfault due to duplicated CFG simplification.
+ result.src = opt = cfg_simplify!(opt.ir::IRCode)
+ end
  end
  if opt isa CodeInfo
  opt.min_world = first(valid_worlds)