ir/passes: Various followups from previous PRs

Rolls up individual review comments from #48066, #48144, #48151.

Author: Keno

base/compiler/ssair/ir.jl

@@ -1244,7 +1244,6 @@ function process_node!(compact::IncrementalCompact, result_idx::Int, inst::Instr
             ssa_rename[idx] = stmt
         else
             result[result_idx][:inst] = stmt
-            result[result_idx][:flag] = flag
             result_idx += 1
         end
     elseif isa(stmt, GotoNode)

base/compiler/ssair/irinterp.jl

@@ -232,7 +232,7 @@ function reprocess_instruction!(interp::AbstractInterpreter,
             (; rt, effects) = abstract_eval_statement_expr(interp, inst, nothing, ir, irsv.mi)
             # All other effects already guaranteed effect free by construction
             if is_nothrow(effects)
-                ir.stmts[idx][:flag] |= IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+                ir.stmts[idx][:flag] |= IR_FLAG_NOTHROW
                 if isa(rt, Const) && is_inlineable_constant(rt.val)
                     ir.stmts[idx][:inst] = quoted(rt.val)
                 end
@@ -242,7 +242,7 @@ function reprocess_instruction!(interp::AbstractInterpreter,
             if mi′ !== irsv.mi # prevent infinite loop
                 rt, nothrow = concrete_eval_invoke(interp, inst, mi′, irsv)
                 if nothrow
-                    ir.stmts[idx][:flag] |= IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+                    ir.stmts[idx][:flag] |= IR_FLAG_NOTHROW
                     if isa(rt, Const) && is_inlineable_constant(rt.val)
                         ir.stmts[idx][:inst] = quoted(rt.val)
                     end

base/compiler/ssair/passes.jl

@@ -805,7 +805,6 @@ end
         isa(rarg, SSAValue) || return nothing
         argdef = compact[rarg][:inst]
     else
-        isa(arg, DataType) || return nothing
         isType(arg) || return nothing
         arg = arg.parameters[1]
     end