(CMPBload {sym} [off] ptr (MOVLconst [c]) mem) => (CMPBconstload {sym} [makeValAndOff(int32(int8(c)),off)] ptr mem)

(TEST(Q|L|W|B)  l:(MOV(Q|L|W|B)load {sym} [off] ptr mem) l2)
        && l == l2
	&& l.Uses == 2
	&& clobber(l) =>
  @l.Block (CMP(Q|L|W|B)constload {sym} [makeValAndOff(0, off)] ptr mem)

// Convert ANDload to MOVload when we can do the AND in a containing TEST op.

	sg := mheap_.sweepgen

	// Find the arena and page index into that arena for this shard.
	ai := mheap_.markArenas[shard/(pagesPerArena/pagesPerSpanRoot)]
	ha := mheap_.arenas[ai.l1()][ai.l2()]
	arenaPage := uint(uintptr(shard) * pagesPerSpanRoot % pagesPerArena)

	// Construct slice of bitmap which we'll iterate over.
	specialsbits := ha.pageSpecials[arenaPage/8:]

	// time here is pretty trivial.
	lock(&mheap_.lock)
	arenas := mheap_.allArenas
	unlock(&mheap_.lock)
	for _, ai := range arenas {
		ha := mheap_.arenas[ai.l1()][ai.l2()]
		clear(ha.pageMarks[:])
	}

	work.bytesMarked = 0
	work.initialHeapLive = gcController.heapLive.Load()
}

// Hooks for other packages

var poolcleanup func()