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Merged
kripken merged 5 commits into from
Oct 23, 2019
Merged

Optimize fmaxf etc. #9689

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a42c4f0
wip
kripken Oct 22, 2019
4577898
wip [ci skip]
kripken Oct 22, 2019
83c36cf
fix
kripken Oct 22, 2019
8fdc7ef
Merge remote-tracking branch 'origin/incoming' into fs
kripken Oct 22, 2019
531da1f
Add tests for negative zero, using a function pointer.
kripken Oct 23, 2019
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5 changes: 5 additions & 0 deletions system/lib/libc/musl/src/math/fmax.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,13 @@ double fmax(double x, double y)
return y;
if (isnan(y))
return x;
// XXX EMSCRIPTEN: use wasm builtins for code size
#ifdef __wasm__
return __builtin_wasm_max_f64(x, y);
#else
/* handle signed zeros, see C99 Annex F.9.9.2 */
if (signbit(x) != signbit(y))
return signbit(x) ? y : x;
return x < y ? y : x;
#endif
}
5 changes: 5 additions & 0 deletions system/lib/libc/musl/src/math/fmaxf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,13 @@ float fmaxf(float x, float y)
return y;
if (isnan(y))
return x;
// XXX EMSCRIPTEN: use wasm builtins for code size
#ifdef __wasm__
return __builtin_wasm_max_f32(x, y);
#else
/* handle signed zeroes, see C99 Annex F.9.9.2 */
if (signbit(x) != signbit(y))
return signbit(x) ? y : x;
return x < y ? y : x;
#endif
}
5 changes: 5 additions & 0 deletions system/lib/libc/musl/src/math/fmin.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,13 @@ double fmin(double x, double y)
return y;
if (isnan(y))
return x;
// XXX EMSCRIPTEN: use wasm builtins for code size
#ifdef __wasm__
return __builtin_wasm_min_f64(x, y);
#else
/* handle signed zeros, see C99 Annex F.9.9.2 */
if (signbit(x) != signbit(y))
return signbit(x) ? x : y;
return x < y ? x : y;
#endif
}
5 changes: 5 additions & 0 deletions system/lib/libc/musl/src/math/fminf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,13 @@ float fminf(float x, float y)
return y;
if (isnan(y))
return x;
// XXX EMSCRIPTEN: use wasm builtins for code size
#ifdef __wasm__
return __builtin_wasm_min_f32(x, y);
#else
/* handle signed zeros, see C99 Annex F.9.9.2 */
if (signbit(x) != signbit(y))
return signbit(x) ? x : y;
return x < y ? x : y;
#endif
}
35 changes: 33 additions & 2 deletions tests/core/test_floatvars.cpp
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Expand Up @@ -11,14 +11,45 @@
#include <cfloat>
#include <cmath>

#define TEST(name, x, y) printf(" " #name "(%.2f, %.2f) => %.2f, %.2f\n", x, y, name(x, y), name(y, x));
#define TEST_ABS(name, x, y) printf("abs " #name "(%.2f, %.2f) => %.2f, %.2f\n", x, y, abs(name(x, y)), abs(name(y, x)));

// fmin etc. are not specced to be sensitive to negative zero, and LLVM does
// depend on that for optimizations, so check only the absolute value there
#define TESTS(name) \

@jgravelle-google jgravelle-google Oct 23, 2019

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yay macros that make things easier to read :)

TEST(name, 0.33, 0.5) \
TEST(name, NAN, 0.5) \
TEST_ABS(name, 0.0, -0.0)

// when calling via a function pointer, the LLVM optimizer isn't involved, and
// the libc implementation does handle negative zero as you'd expect
#define PTR_TESTS(name, ptr) \
puts("ptr " #name); \
ptr = &name; \
TEST(ptr, 0.33, 0.5) \
TEST(ptr, NAN, 0.5) \
TEST(ptr, 0.0, -0.0)

// make it look like these are externally modifiable so the optimizer doesn't
// trivially remove the function pointer
double (*funcd)(double, double);
float (*funcf)(float, float);

int main(int argc, char **argv) {
float x = 1.234, y = 3.5, q = 0.00000001;
y *= 3;
int z = x < y;
printf("*%d,%d,%.1f,%d,%.4f,%.2f*\n", z, int(y), y, (int)x, x, q);

printf("%.2f, %.2f, %.2f, %.2f\n", fmin(0.5, 3.3), fmin(NAN, 3.3),
fmax(0.5, 3.3), fmax(NAN, 3.3));
TESTS(fmin);
TESTS(fmax);
TESTS(fminf);
TESTS(fmaxf);

PTR_TESTS(fmin, funcd);
PTR_TESTS(fmax, funcd);
PTR_TESTS(fminf, funcf);
PTR_TESTS(fmaxf, funcf);

printf("small: %.10f\n", argc * 0.000001);

Expand Down
29 changes: 28 additions & 1 deletion tests/core/test_floatvars.out
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Original file line number Diff line number Diff line change
@@ -1,4 +1,31 @@
*1,10,10.5,1,1.2340,0.00*
0.50, 3.30, 3.30, 3.30
fmin(0.33, 0.50) => 0.33, 0.33
fmin(nan, 0.50) => 0.50, 0.50
abs fmin(0.00, -0.00) => 0.00, 0.00
fmax(0.33, 0.50) => 0.50, 0.50
fmax(nan, 0.50) => 0.50, 0.50
abs fmax(0.00, -0.00) => 0.00, 0.00
fminf(0.33, 0.50) => 0.33, 0.33
fminf(nan, 0.50) => 0.50, 0.50
abs fminf(0.00, -0.00) => 0.00, 0.00
fmaxf(0.33, 0.50) => 0.50, 0.50
fmaxf(nan, 0.50) => 0.50, 0.50
abs fmaxf(0.00, -0.00) => 0.00, 0.00
ptr fmin
funcd(0.33, 0.50) => 0.33, 0.33
funcd(nan, 0.50) => 0.50, 0.50
funcd(0.00, -0.00) => -0.00, -0.00
ptr fmax
funcd(0.33, 0.50) => 0.50, 0.50
funcd(nan, 0.50) => 0.50, 0.50
funcd(0.00, -0.00) => 0.00, 0.00
ptr fminf
funcf(0.33, 0.50) => 0.33, 0.33
funcf(nan, 0.50) => 0.50, 0.50
funcf(0.00, -0.00) => -0.00, -0.00
ptr fmaxf
funcf(0.33, 0.50) => 0.50, 0.50
funcf(nan, 0.50) => 0.50, 0.50
funcf(0.00, -0.00) => 0.00, 0.00
small: 0.0000010000
double: 1123456789012345651200.000000