The sched.c analogue of §47's live-length slider. A close=2 with IDENTICAL registers is not a regalloc
residual — it is sched2's rank_for_schedule falling through to its final tiebreak,
'return INSN_LUID(tmp) - INSN_LUID(tmp2)', i.e. position in the .greg stream. Root cause is upstream in
sched1: adjust_priority/birthing_insn_p gives every register-DEFINING insn LAUNCH_PRIORITY 0x7f000001
(sched.c:2574), which sinks the un-boosted insn past its rivals and inverts the LUID order.
THE DIAL: materialize a call argument's sign-extension into an explicit s32 temp, placed AFTER the
intervening statement (adjacent to the load, combine fuses lhu+sll+sra into one lh and you LOSE 3 insns;
the intervening store blocks the fusion). Widen the prototype to (s32,s32) so the call adds no conversion.
Same instructions emitted, earlier INSN_LUID -> the tie flips.
Zero-byte dial family is now three: §47 live-length (global.c), §48-A1/A4 sink-init/sink-call
(global.c/local-alloc), §49 LUID (sched.c). Method: -dS -dR dumps the ready lists + priorities; equal
priorities => you are on a LUID tiebreak => the fix is PLACEMENT, not registers.
11 of 12 wave cores now MATCH.
Drew T
a30500eecf