Repackage I.@e. result to reduce wasted space

Author: HenryHRich

jsrc/viavx.c

@@ -1141,6 +1141,12 @@ inplace:;
   GAT0(x,INT,6,1); xv=AV1(x);
   xv[0]=mode; xv[1]=n; xv[2]=k; /* noavx xv[3]=jt->min; */ xv[4]=(I)fntbl[FNTABLEPREFIX+fnx][bighash]; /* xv[5]=ztypefromitype[mode&IIOPMSK]; */
   zv[0]=incorp(x); zv[1]=incorp(h);
+ }else if(unlikely((mode&IIOPMSK)==IIFBEPS)){
+  // I.@e. initially allocated a maximum-sized result, which might be colossally wasteful of space (but not of time or cache footprint)
+  // if the block is mostly empty, reallocate it & copy a right-sized block
+  if(((allosize(z)-AKXR(1))>>(LGSZI+1))>MAX(AN(z),12)){  // if a smaller block would serve (but not if the block is already small)
+   GATV0(h,INT,AN(z),1); JMC(IAV1(h),IAV1(z),SZI*AN(z),0) z=h;  // repackage the result in a right-sized block
+  }
  }
  RZ(z=EPILOGNORET(z));
  // Since EPILOG may have rewritten AM, and IFORKEY never returns to the parser, we can store the FORKEY result in AM.

test/g422os.ijs

@@ -7,13 +7,16 @@ NB. x{/:~y (order statistics) -------------------------------------------
 (/:~y) -: (i.#y) ({/:~)"0 1 y=: 0.1 * 100 ?@$ 10000
 (/:~y) -: (i.#y) ({/:~)"0 1 y=:       100   $ 10000
 (/:~y) -: (i.#y) ({/:~)"0 1 y=:       100   $ 34.5
+NB. y -: (/:~y) {~ (i.#y) ({/:)"0 1 y=:       100 ?@$ 60
 
 y=: 1000 ?@$ 600
 x=: n -~ 20 ?@$ +:n=: #y
 (x{/:~y) -: x ({/:~)"0 1 y
 y=: 0.1 * y
 (x{/:~y) -: x ({/:~)"0 1 y
 
+0 0 0 0 1 3 3 -: 0 0 0 0 1 2 2 ({ /:) 0 1 4 2 5 6 3
+
 NB. Verify special code used
 y=: 1000 ?@$ 1e6  NB. avoid small-range!
 THRESHOLD +. 0.7 > %/ 10000&(6!:2) '5 ({ /:) y' ,: '5 ({ /:"]) y'    NB. 0.64 on vs2019 avx2

test/gibs.ijs

@@ -94,6 +94,9 @@ y test y
 x test y [ x=: 811 0$a: [ y=: 947 0$a:
 y test y
 
+(600 ?@$ 1000) (I.@e. -: I.@(e."e.)) 465 ?@$ 1000
+(7!:2 'a I.@e. i. 4') > 2 * (7!:2 'a I.@(e."e.) i. 4') [ a =. i. 1000
+
 4!:55 ;:'a b f f1 g mean q r test u x y'