Compile cmm file for register allocator stats

I'm trying to write a unit test for the graph coloring register allocator and to start I'm trying to write a function that will compile a cmm file and return register allocation stats (that can then be asserted against). It should be less cumbersome to use than cmmNativeGen.

mentioned in issue #12744

changed weight to 0

added NCG backend Ttask Trac import labels

assigned to @trac-tjakway

The issue stems from RegAlloc.Graph.Main lines 100-106:

-- If any of these dump flags are turned on we want to hang on to
-- intermediate structures in the allocator - otherwise tell the
-- allocator to ditch them early so we don't end up creating space leaks.
let dump = or
    [ dopt Opt_D_dump_asm_regalloc_stages dflags
    , dopt Opt_D_dump_asm_stats dflags
    , dopt Opt_D_dump_asm_conflicts dflags ]

Without the dump flags the intermediate structures needed for testing are scrapped. I propose adding a flag to keep the intermediates without printing them.

changed the description

Trac metadata

Trac field	Value
Differential revisions	D2621 → D2638

I've submitted the first patch with a test for avoiding unnecessary spills and reloads.

mentioned in commit 0e586529

closed

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

added Plow label