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soft-fp64: Store sign value as 0 or 0x80000000 

...instead of 0 or 1.  Many places the sign bit is extracted, then later
put back in the same position.  This saves some left-shift operations.

Results on the 308 shaders extracted from the fp64 portion of the OpenGL
CTS:

Tiger Lake and Ice Lake had similar results. (Tiger Lake shown)
total instructions in shared programs: 848106 -> 844558 (-0.42%)
instructions in affected programs: 833480 -> 829932 (-0.43%)
helped: 106
HURT: 1
helped stats (abs) min: 1 max: 995 x̄: 33.48 x̃: 12
helped stats (rel) min: 0.15% max: 2.20% x̄: 0.60% x̃: 0.35%
HURT stats (abs)   min: 1 max: 1 x̄: 1.00 x̃: 1
HURT stats (rel)   min: <.01% max: <.01% x̄: <.01% x̃: <.01%
95% mean confidence interval for instructions value: -51.88 -14.43
95% mean confidence interval for instructions %-change: -0.71% -0.47%
Instructions are helped.

total cycles in shared programs: 6969125 -> 6962024 (-0.10%)
cycles in affected programs: 6717689 -> 6710588 (-0.11%)
helped: 78
HURT: 7
helped stats (abs) min: 2 max: 2083 x̄: 110.27 x̃: 56
helped stats (rel) min: <.01% max: 0.30% x̄: 0.11% x̃: 0.11%
HURT stats (abs)   min: 2 max: 1340 x̄: 214.29 x̃: 4
HURT stats (rel)   min: 0.01% max: 0.71% x̄: 0.13% x̃: 0.02%
95% mean confidence interval for cycles value: -144.02 -23.06
95% mean confidence interval for cycles %-change: -0.12% -0.07%
Cycles are helped.

total spills in shared programs: 814 -> 759 (-6.76%)
spills in affected programs: 814 -> 759 (-6.76%)
helped: 2
HURT: 1

total fills in shared programs: 2488 -> 2412 (-3.05%)
fills in affected programs: 2488 -> 2412 (-3.05%)
helped: 2
HURT: 1

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4142>
This commit is contained in:
Ian Romanick 2020-03-02 16:37:58 -08:00 committed by Marge Bot
parent 598e2fc6a1
commit de4acd8816
1 changed files with 16 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
src/compiler/glsl/float64.glsl
View File

@ -165,7 +165,7 @@ __fne64(uint64_t a, uint64_t b)
uint
__extractFloat64Sign(uint64_t a)
{
return unpackUint2x32(a).y >> 31;
return unpackUint2x32(a).y & 0x80000000u;
}
/* Returns true if the 64-bit value formed by concatenating `a0' and `a1' is less
@ -376,7 +376,7 @@ __packFloat64(uint zSign, int zExp, uint zFrac0, uint zFrac1)
{
uvec2 z;
z.y = (zSign << 31) + (uint(zExp) << 20) + zFrac0;
z.y = zSign + (uint(zExp) << 20) + zFrac0;
z.x = zFrac1;
return packUint2x32(z);
}
@ -682,7 +682,7 @@ __fadd64(uint64_t a, uint64_t b)
if (expDiff < 0) {
if (bExp == 0x7FF) {
bool propagate = (bFracHi | bFracLo) != 0u;
return mix(__packFloat64(aSign ^ 1u, 0x7ff, 0u, 0u), __propagateFloat64NaN(a, b), propagate);
return mix(__packFloat64(aSign ^ 0x80000000u, 0x7ff, 0u, 0u), __propagateFloat64NaN(a, b), propagate);
}
expDiff = mix(expDiff, expDiff + 1, aExp == 0);
aFracHi = mix(aFracHi | 0x40000000u, aFracHi, aExp == 0);
@ -690,7 +690,7 @@ __fadd64(uint64_t a, uint64_t b)
bFracHi |= 0x40000000u;
__sub64(bFracHi, bFracLo, aFracHi, aFracLo, zFrac0, zFrac1);
zExp = bExp;
aSign ^= 1u;
aSign ^= 0x80000000u;
--zExp;
return __normalizeRoundAndPackFloat64(aSign, zExp - 10, zFrac0, zFrac1);
}
@ -721,8 +721,8 @@ __fadd64(uint64_t a, uint64_t b)
zexp_normal = true;
}
zExp = mix(bExp, aExp, blta);
aSign = mix(aSign ^ 1u, aSign, blta);
uint64_t retval_0 = __packFloat64(uint(FLOAT_ROUNDING_MODE == FLOAT_ROUND_DOWN), 0, 0u, 0u);
aSign = mix(aSign ^ 0x80000000u, aSign, blta);
uint64_t retval_0 = __packFloat64(uint(FLOAT_ROUNDING_MODE == FLOAT_ROUND_DOWN) << 31, 0, 0u, 0u);
uint64_t retval_1 = __normalizeRoundAndPackFloat64(aSign, zExp - 11, zFrac0, zFrac1);
return mix(retval_0, retval_1, zexp_normal);
}
@ -1021,7 +1021,7 @@ __fp32_to_uint64(float f)
uint a = floatBitsToUint(f);
uint aFrac = a & 0x007FFFFFu;
int aExp = int((a>>23) & 0xFFu);
uint aSign = a>>31;
uint aSign = a & 0x80000000u;
uint zFrac0 = 0u;
uint zFrac1 = 0u;
uint zFrac2 = 0u;
@ -1050,7 +1050,7 @@ __fp32_to_int64(float f)
uint a = floatBitsToUint(f);
uint aFrac = a & 0x007FFFFFu;
int aExp = int((a>>23) & 0xFFu);
uint aSign = a>>31;
uint aSign = a & 0x80000000u;
uint zFrac0 = 0u;
uint zFrac1 = 0u;
uint zFrac2 = 0u;
@ -1084,10 +1084,10 @@ __int64_to_fp64(int64_t a)
uint64_t absA = mix(uint64_t(a), uint64_t(-a), a < 0);
uint aFracHi = __extractFloat64FracHi(absA);
uvec2 aFrac = unpackUint2x32(absA);
uint zSign = uint(a < 0);
uint zSign = uint(unpackInt2x32(a).y) & 0x80000000u;
if ((aFracHi & 0x80000000u) != 0u) {
return mix(0ul, __packFloat64(1, 0x434, 0u, 0u), a < 0);
return mix(0ul, __packFloat64(0x80000000u, 0x434, 0u, 0u), a < 0);
}
return __normalizeRoundAndPackFloat64(zSign, 0x432, aFrac.y, aFrac.x);
@ -1145,7 +1145,7 @@ __int_to_fp64(int a)
uint zFrac1 = 0u;
if (a==0)
return __packFloat64(0u, 0, 0u, 0u);
uint zSign = uint(a < 0);
uint zSign = uint(a) & 0x80000000u;
uint absA = mix(uint(a), uint(-a), a < 0);
int shiftCount = __countLeadingZeros32(absA) - 11;
if (0 <= shiftCount) {
@ -1181,7 +1181,7 @@ __bool_to_fp64(bool a)
float
__packFloat32(uint zSign, int zExp, uint zFrac)
{
return uintBitsToFloat((zSign<<31) + (uint(zExp)<<23) + zFrac);
return uintBitsToFloat(zSign + (uint(zExp)<<23) + zFrac);
}
/* Takes an abstract floating-point value having sign `zSign', exponent `zExp',
@ -1261,7 +1261,7 @@ __fp64_to_fp32(uint64_t __a)
uint aSign = __extractFloat64Sign(__a);
if (aExp == 0x7FF) {
__shortShift64Left(a.y, a.x, 12, a.y, a.x);
float rval = uintBitsToFloat((aSign<<31) | 0x7FC00000u | (a.y>>9));
float rval = uintBitsToFloat(aSign | 0x7FC00000u | (a.y>>9));
rval = mix(__packFloat32(aSign, 0xFF, 0u), rval, (aFracHi | aFracLo) != 0u);
return rval;
}
@ -1289,7 +1289,7 @@ __uint64_to_fp32(uint64_t __a)
float
__int64_to_fp32(int64_t __a)
{
uint aSign = uint(__a < 0);
uint aSign = uint(unpackInt2x32(__a).y) & 0x80000000u;
uint64_t absA = mix(uint64_t(__a), uint64_t(-__a), __a < 0);
uvec2 aFrac = unpackUint2x32(absA);
int shiftCount = mix(__countLeadingZeros32(aFrac.y) - 33,
@ -1313,7 +1313,7 @@ __fp32_to_fp64(float f)
uint a = floatBitsToUint(f);
uint aFrac = a & 0x007FFFFFu;
int aExp = int((a>>23) & 0xFFu);
uint aSign = a>>31;
uint aSign = a & 0x80000000u;
uint zFrac0 = 0u;
uint zFrac1 = 0u;
@ -1322,7 +1322,7 @@ __fp32_to_fp64(float f)
uint nanLo = 0u;
uint nanHi = a<<9;
__shift64Right(nanHi, nanLo, 12, nanHi, nanLo);
nanHi |= ((aSign<<31) | 0x7FF80000u);
nanHi |= aSign | 0x7FF80000u;
return packUint2x32(uvec2(nanLo, nanHi));
}
return __packFloat64(aSign, 0x7FF, 0u, 0u);