kit

6_5_33_regalloc_spill.c (1479B)

---

 /* Regalloc spill stress.
  *
  * Each `xN + 0` arg is a binop that leaves a register-resident rvalue on
  * the cg value stack until cg_call materializes it. With 12 simultaneously
  * accumulating arg values and a 10-INT scratch pool on aarch64, several
  * code paths the spill driver must handle get exercised:
  *
  *   - alloc_reg_or_spill returning REG_NONE on pool exhaustion and
  *     picking the deepest unpinned RES_REG via pick_victim, then routing
  *     it through spill_reg / take_spill_slot.
  *   - ensure_reg reloading SPILLED args inside cg_call's arg-pop loop,
  *     consuming pool slots as it goes.
  *   - The avs-in-flight fallback: once cg_call has popped enough RES_REG
  *     args into avs[] to drain the pool, alloc_reg_or_spill finds no
  *     stack victim (later args are SPILLED, earlier args are off-stack
  *     in avs[]) and falls back to spilling an OPK_REG avs entry through
  *     spill_avs_victim, rewriting it to OPK_LOCAL so the backend's call
  *     lowering loads from the spill slot.
  *
  * 1+2+...+12 = 78. */
 
 int sum12(int a, int b, int c, int d, int e, int f, int g, int h, int i, int j,
           int k, int l) {
   return a + b + c + d + e + f + g + h + i + j + k + l;
 }
 
 int test_main(void) {
   int x1 = 1, x2 = 2, x3 = 3, x4 = 4, x5 = 5, x6 = 6;
   int x7 = 7, x8 = 8, x9 = 9, x10 = 10, x11 = 11, x12 = 12;
   return sum12(x1 + 0, x2 + 0, x3 + 0, x4 + 0, x5 + 0, x6 + 0, x7 + 0, x8 + 0,
                x9 + 0, x10 + 0, x11 + 0, x12 + 0);
 }