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[VENTUS][fix] Fix float precision issue in libclc for ventus 

There are many potential precision bugs in libclc, especially the functions
under `libclc/riscv32/lib/compiler-rt` directory.
This commit is contained in:
zhoujingya 2023-10-30 10:59:59 +08:00 committed by zhoujing
parent 91b9888732
commit dfd2affa51
5 changed files with 79 additions and 35 deletions
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16
libclc/riscv32/lib/compiler-rt/floatdidf.cl
View File

@ -22,32 +22,32 @@ double __floatdidf(di_int a) {
const unsigned N = sizeof(di_int) * 8;
const di_int s = a >> (N - 1);
a = (a ^ s) - s;
int sd = N - __builtin_clzll(a);
int sd = N - clz64(a);
int e = sd - 1;
if (sd > 53) {
if (sd > DBL_MANT_DIG) {
switch (sd) {
case 53 + 1:
case DBL_MANT_DIG + 1:
a <<= 1;
break;
case 53 + 2:
case DBL_MANT_DIG + 2:
break;
default:
a = ((du_int)a >> (sd - (53 + 2))) |
((a & ((du_int)(-1) >> ((N + 53 + 2) - sd))) != 0);
a = ((du_int)a >> (sd - (DBL_MANT_DIG + 2))) |
((a & ((du_int)(-1) >> ((N + DBL_MANT_DIG + 2) - sd))) != 0);
};
a |= (a & 4) != 0;
++a;
a >>= 2;
if (a & ((du_int)1 << 53)) {
if (a & ((du_int)1 << DBL_MANT_DIG)) {
a >>= 1;
++e;
}
} else {
a <<= (53 - sd);
a <<= (DBL_MANT_DIG - sd);
}
double_bits fb;
fb.u.s.high = ((su_int)s & 0x80000000) | ((su_int)(e + 1023) << 20) |

16
libclc/riscv32/lib/compiler-rt/floatdisf.cl
View File

@ -22,32 +22,32 @@ float __floatdisf(di_int a) {
const unsigned N = sizeof(di_int) * 8;
const di_int s = a >> (N - 1);
a = (a ^ s) - s;
int sd = N - __builtin_clzll(a);
int sd = N - clz64(a);
si_int e = sd - 1;
if (sd > 24) {
if (sd > FLT_MANT_DIG) {
switch (sd) {
case 24 + 1:
case FLT_MANT_DIG + 1:
a <<= 1;
break;
case 24 + 2:
case FLT_MANT_DIG + 2:
break;
default:
a = ((du_int)a >> (sd - (24 + 2))) |
((a & ((du_int)(-1) >> ((N + 24 + 2) - sd))) != 0);
a = ((du_int)a >> (sd - (FLT_MANT_DIG + 2))) |
((a & ((du_int)(-1) >> ((N + FLT_MANT_DIG + 2) - sd))) != 0);
};
a |= (a & 4) != 0;
++a;
a >>= 2;
if (a & ((du_int)1 << 24)) {
if (a & ((du_int)1 << FLT_MANT_DIG)) {
a >>= 1;
++e;
}
} else {
a <<= (24 - sd);
a <<= (FLT_MANT_DIG - sd);
}
float_bits fb;
fb.u =

14
libclc/riscv32/lib/compiler-rt/floatundidf.cl
View File

@ -22,30 +22,30 @@ double __floatundidf(du_int a) {
const unsigned N = sizeof(du_int) * 8;
int sd = N - __builtin_clzll(a);
int e = sd - 1;
if (sd > 53) {
if (sd > DBL_MANT_DIG) {
switch (sd) {
case 53 + 1:
case DBL_MANT_DIG + 1:
a <<= 1;
break;
case 53 + 2:
case DBL_MANT_DIG + 2:
break;
default:
a = (a >> (sd - (53 + 2))) |
((a & ((du_int)(-1) >> ((N + 53 + 2) - sd))) != 0);
a = (a >> (sd - (DBL_MANT_DIG + 2))) |
((a & ((du_int)(-1) >> ((N + DBL_MANT_DIG + 2) - sd))) != 0);
};
a |= (a & 4) != 0;
++a;
a >>= 2;
if (a & ((du_int)1 << 53)) {
if (a & ((du_int)1 << DBL_MANT_DIG)) {
a >>= 1;
++e;
}
} else {
a <<= (53 - sd);
a <<= (DBL_MANT_DIG - sd);
}
double_bits fb;
fb.u.s.high = ((su_int)(e + 1023) << 20) | ((su_int)(a >> 32) & 0x000FFFFF);

27
libclc/riscv32/lib/compiler-rt/floatundisf.cl
View File

@ -17,18 +17,19 @@
// seee eeee emmm mmmm mmmm mmmm mmmm mmmm
typedef union {
int u;
float f;
} float_bits;
#ifdef cl_khr_fp64
#pragma OPENCL EXTENSION cl_khr_fp64 : enable
#include "types.h"
float __floatundisf(long a) {
if (a == 0)
return 0.0F;
const unsigned N = sizeof(long) * 8;
int sd = N - __builtin_clzll(a); // number of significant digits
int sd = N - clz64(a); // number of significant digits
int e = sd - 1; // 8 exponent
if (sd > 24) {
if (sd > FLT_MANT_DIG) {
// start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
// finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
// 12345678901234567890123456
@ -37,27 +38,27 @@ float __floatundisf(long a) {
// Q = bit FLT_MANT_DIG bits to the right of 1
// R = "or" of all bits to the right of Q
switch (sd) {
case 24 + 1:
case FLT_MANT_DIG + 1:
a <<= 1;
break;
case 24 + 2:
case FLT_MANT_DIG + 2:
break;
default:
a = (a >> (sd - (24 + 2))) |
((a & ((long)(-1) >> ((N + 24+ 2) - sd))) != 0);
a = (a >> (sd - (FLT_MANT_DIG + 2))) |
((a & ((long)(-1) >> ((N + FLT_MANT_DIG+ 2) - sd))) != 0);
};
// finish:
a |= (a & 4) != 0; // Or P into R
++a; // round - this step may add a significant bit
a >>= 2; // dump Q and R
// a is now rounded to FLT_MANT_DIG or FLT_MANT_DIG+1 bits
if (a & ((long)1 << 24)) {
if (a & ((long)1 << FLT_MANT_DIG)) {
a >>= 1;
++e;
}
// a is now rounded to FLT_MANT_DIG bits
} else {
a <<= (24 - sd);
a <<= (FLT_MANT_DIG - sd);
// a is now rounded to FLT_MANT_DIG bits
}
float_bits fb;
@ -65,3 +66,5 @@ float __floatundisf(long a) {
((unsigned)a & 0x007FFFFF); // mantissa
return fb.f;
}
#endif

41
libclc/riscv32/lib/compiler-rt/types.h
View File

@ -1,6 +1,8 @@
#ifndef TYPES_H
#define TYPES_H
#include <float.h>
typedef char char2 __attribute__((__ext_vector_type__(2)));
typedef char char3 __attribute__((__ext_vector_type__(3)));
typedef char char4 __attribute__((__ext_vector_type__(4)));
@ -525,4 +527,43 @@ do { \
(d) = __u.value; \
} while (0)
static int __attribute__((noinline)) clzl(unsigned long x)
//static int inline clzl(unsigned long x)
{
for (int i = 0; i != 64; ++i)
if ((x >> (63 - i)) & 1)
return i;
return 0;
}
static int ctz64(unsigned long x)
{
int r = 63;
x &= ~x + 1;
if (x & 0x00000000FFFFFFFF) r -= 32;
if (x & 0x0000FFFF0000FFFF) r -= 16;
if (x & 0x00FF00FF00FF00FF) r -= 8;
if (x & 0x0F0F0F0F0F0F0F0F) r -= 4;
if (x & 0x3333333333333333) r -= 2;
if (x & 0x5555555555555555) r -= 1;
return r;
}
static int clz64(unsigned long x) {
int r = 0;
if ((x & 0xFFFFFFFF00000000) == 0) r += 32, x <<= 32;
if ((x & 0xFFFF000000000000) == 0) r += 16, x <<= 16;
if ((x & 0xFF00000000000000) == 0) r += 8, x <<= 8;
if ((x & 0xF000000000000000) == 0) r += 4, x <<= 4;
if ((x & 0xC000000000000000) == 0) r += 2, x <<= 2;
if ((x & 0x8000000000000000) == 0) r += 1, x <<= 1;
return r;
}
#endif // TYPES_H