uint16_t i;
    float SigRe[16],*pSigRe;
    pSigRe = SigRe;
    for(i=0; i<16; i++) SigRe[i] = 2.*(i+1);
    for(i=0; i<16; i++) *pSigRe++ = log2f(*pSigRe) * 15.0515;
    for(i=0; i<16; i++) printf("i = %u SigRe[%u] = %f12.5\n",i,i,SigRe[i]);

    for(i=0; i<16; i++) SigRe[i] = 2.*(i+1);
    for(i=0; i<16; i++) SigRe[i] = log2f(SigRe[i]) * 15.0515;
    for(i=0; i<16; i++) printf("i = %u SigRe[%u] = %f12.5\n",i,i,SigRe[i]);

i = 0 SigRe[0] = 30.10300112.5
i = 1 SigRe[1] = 38.90756212.5
i = 2 SigRe[2] = 45.15449912.5
i = 3 SigRe[3] = 50.00000012.5
i = 4 SigRe[4] = 53.95906412.5
i = 5 SigRe[5] = 57.30640412.5
i = 6 SigRe[6] = 60.20600112.5
i = 7 SigRe[7] = 62.76362612.5
i = 8 SigRe[8] = 65.05149812.5
i = 9 SigRe[9] = 67.12113212.5
i = 10 SigRe[10] = 69.01056712.5
i = 11 SigRe[11] = 70.74866512.5
i = 12 SigRe[12] = 72.35790312.5
i = 13 SigRe[13] = 73.85606412.5
i = 14 SigRe[14] = 75.25750012.5
i = 15 SigRe[15] = -1913.32995612.5
i = 0 SigRe[0] = 15.05150012.5
i = 1 SigRe[1] = 30.10300112.5
i = 2 SigRe[2] = 38.90756212.5
i = 3 SigRe[3] = 45.15449912.5
i = 4 SigRe[4] = 50.00000012.5
i = 5 SigRe[5] = 53.95906412.5
i = 6 SigRe[6] = 57.30640412.5
i = 7 SigRe[7] = 60.20600112.5
i = 8 SigRe[8] = 62.76362612.5
i = 9 SigRe[9] = 65.05149812.5
i = 10 SigRe[10] = 67.12113212.5
i = 11 SigRe[11] = 69.01056712.5
i = 12 SigRe[12] = 70.74866512.5
i = 13 SigRe[13] = 72.35790312.5
i = 14 SigRe[14] = 73.85606412.5
i = 15 SigRe[15] = 75.25750012.5
Hello world!

**********************************************************************
-O0

000320 490e LDR r1,|L8.860|
000322 6008 STR r0,[r1,#0] ; SigRe
;;;3771 pSigRe = SigRe;
000324 460c MOV r4,r1
;;;3772 for (uint32_t i = FFT_N; i--; ) {
000326 f44f6680 MOV r6,#0x400
00032a e00f B |L8.844|
|L8.812|
;;;3775 *pSigRe++ = log2f(*pSigRe) * 15.0515;
00032c 6820 LDR r0,[r4,#0]
00032e f7fffffe BL log2f
000332 900b STR r0,[sp,#0x2c]
000334 f7fffffe BL __aeabi_f2d
000338 4680 MOV r8,r0
00033a 4a14 LDR r2,|L8.908|
00033c 4b14 LDR r3,|L8.912|
00033e f7fffffe BL __aeabi_dmul
000342 e9cd010c STRD r0,r1,[sp,#0x30]
000346 f7fffffe BL __aeabi_d2f
00034a c401 STM r4!,{r0}
|L8.844|
00034c 1e30 SUBS r0,r6,#0 ;3772
00034e f1a60601 SUB r6,r6,#1 ;3772
000352 d1eb BNE |L8.812|
|L8.860|
DCD SigRe
|L8.908|
DCD 0x353f7cee
|L8.912|
DCD 0x402e1a5e

********************************************************************************
-O0

000320 490e LDR r1,|L8.860|
000322 6008 STR r0,[r1,#0] ; SigRe
;;;3771 pSigRe = SigRe;
000324 460c MOV r4,r1
;;;3772 for (uint32_t i = FFT_N; i--; ) {
000326 f44f6680 MOV r6,#0x400
00032a e010 B |L8.846|
|L8.812|
;;;3775 *pSigRe = log2f(*pSigRe) * 15.0515;
00032c 6820 LDR r0,[r4,#0]
00032e f7fffffe BL log2f
000332 900b STR r0,[sp,#0x2c]
000334 f7fffffe BL __aeabi_f2d
000338 4680 MOV r8,r0
00033a 4a14 LDR r2,|L8.908|
00033c 4b14 LDR r3,|L8.912|
00033e f7fffffe BL __aeabi_dmul
000342 e9cd010c STRD r0,r1,[sp,#0x30]
000346 f7fffffe BL __aeabi_d2f
00034a 6020 STR r0,[r4,#0]
;;;3776 pSigRe++;
00034c 1d24 ADDS r4,r4,#4
|L8.846|
00034e 1e30 SUBS r0,r6,#0 ;3772
000350 f1a60601 SUB r6,r6,#1 ;3772
000354 d1ea BNE |L8.812|
|L8.860|
DCD SigRe
|L8.908|
DCD 0x353f7cee
|L8.912|
DCD 0x402e1a5e

********************************************************************************
-O3 -Otime

;;;3775 *pSigRe++ = log2f(*pSigRe) * 15.0515;

000264 f24038ff MOV r8,#0x3ff ;3722

0002d8 4c0a LDR r4,|L8.772|
0002da 4d17 LDR r5,|L8.824|
0002dc 4e17 LDR r6,|L8.828|
|L8.734|
0002de 6820 LDR r0,[r4,#0] ;3775
0002e0 f7fffffe BL log2f
0002e4 f7fffffe BL __aeabi_f2d
0002e8 462a MOV r2,r5 ;3775
0002ea 4633 MOV r3,r6 ;3775
0002ec f7fffffe BL __aeabi_dmul
0002f0 f7fffffe BL __aeabi_d2f
0002f4 f8440b04 STR r0,[r4],#4 ;3775
0002f8 f1b80801 SUBS r8,r8,#1 ;3775
0002fc d2ef BCS |L8.734|

|L8.772|
DCD extram
|L8.824|
DCD 0x353f7cee
|L8.828|
DCD 0x402e1a5e


********************************************************************************
-O3 -Otime

;;;3771 pSigRe = SigRe;
;;;3772 for (uint32_t i = FFT_N; i--; ) {
;;;3775 *pSigRe = log2f(*pSigRe) * 15.0515;
;;;3776 pSigRe++;
;;;3777 }
000264 f24038ff MOV r8,#0x3ff ;3722

0002d8 4c0a LDR r4,|L8.772|
0002da 4d17 LDR r5,|L8.824|
0002dc 4e17 LDR r6,|L8.828|
|L8.734|
0002de 6820 LDR r0,[r4,#0] ;3775
0002e0 f7fffffe BL log2f
0002e4 f7fffffe BL __aeabi_f2d
0002e8 462a MOV r2,r5 ;3775
0002ea 4633 MOV r3,r6 ;3775
0002ec f7fffffe BL __aeabi_dmul
0002f0 f7fffffe BL __aeabi_d2f
0002f4 f8440b04 STR r0,[r4],#4 ;3775
0002f8 f1b80801 SUBS r8,r8,#1 ;3775
0002fc d2ef BCS |L8.734|

|L8.772|
DCD extram
|L8.824|
DCD 0x353f7cee
|L8.828|
DCD 0x402e1a5e

***********************************************************************
-O3
;;;3775 *pSigRe++ = log2f(*pSigRe) * 15.0515;

000208 f24035ff MOV r5,#0x3ff

000280 4c09 LDR r4,|L8.680|
000282 4e12 LDR r6,|L8.716|
000284 4f12 LDR r7,|L8.720|
|L8.646|
000286 6820 LDR r0,[r4,#0] ;3775
000288 f7fffffe BL log2f
00028c f7fffffe BL __aeabi_f2d
000290 4632 MOV r2,r6 ;3775
000292 463b MOV r3,r7 ;3775
000294 f7fffffe BL __aeabi_dmul
000298 f7fffffe BL __aeabi_d2f
00029c c401 STM r4!,{r0} ;3775
00029e 1e6d SUBS r5,r5,#1 ;3775
0002a0 d2f1 BCS |L8.646|

|L8.680|
DCD extram
|L8.716|
DCD 0x353f7cee
|L8.720|
DCD 0x402e1a5e

p = &array[0];
do {
i0 = *p++;
...
i1 = *p++;
...
i2 = *p++;
...
i3 = *p++;
} while ();

p = &array[0] - 4;
do {
LDR R1, [R0, #16]!
...
LDR R2, [R0, #4]
...
LDR R3, [R0, #8]
...
LDR R4, [R0, #12]
} while ();

do {
LDR R1, [R0], #4
...
LDR R2, [R0], #4
...
LDR R3, [R0], #4
...
LDR R4, [R0], #4
} while ();

template<class... Ts> struct overloaded : Ts... {};

template<class... Ts> overloaded(Ts...) -> overloaded<Ts...>;

  

// usage

overloaded {[](auto arg) {}, [](double arg) {}};