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Add benchmarks for floating point math
This adds comparisons among the compiler-builtins function, system functions if available, and optionally handwritten assembly. These also help us identify inconsistencies between this crate and system functions, which may otherwise go unnoticed if intrinsics get lowered to inline operations rather than library calls.
1 parent 841bdaf commit 175b45d

14 files changed

+1730
-2
lines changed

‎ci/run.sh

+4-1
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,9 @@ set -eux
44

55
target="${1:-}"
66

7-
if [ -z "${1:-}" ]; then
7+
export RUST_BACKTRACE="${RUST_BACKTRACE:-full}"
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9+
if [ -z "$target" ]; then
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host_target=$(rustc -vV | awk '/^host/ { print $2 }')
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echo "Defaulted to host target $host_target"
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target="$host_target"
@@ -24,6 +26,7 @@ else
2426
run="cargo test --manifest-path testcrate/Cargo.toml --no-fail-fast --target $target"
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$run
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$run --release
29+
$run --benches
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$run --features c
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$run --features c --release
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$run --features no-asm

‎testcrate/Cargo.toml

+44-1
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,10 @@ path = ".."
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default-features = false
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features = ["public-test-deps"]
2323

24+
[dev-dependencies]
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criterion = { version = "0.5.1", default-features = false }
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paste = "1.0.15"
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[target.'cfg(all(target_arch = "arm", not(any(target_env = "gnu", target_env = "musl")), target_os = "linux"))'.dev-dependencies]
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test = { git = "https://github.com/japaric/utest" }
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utest-cortex-m-qemu = { default-features = false, git = "https://github.com/japaric/utest" }
@@ -34,6 +38,45 @@ no-f16-f128 = ["compiler_builtins/no-f16-f128"]
3438
mem = ["compiler_builtins/mem"]
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mangled-names = ["compiler_builtins/mangled-names"]
3640
# Skip tests that rely on f128 symbols being available on the system
37-
no-sys-f128 = ["no-sys-f128-int-convert"]
41+
no-sys-f128 = ["no-sys-f128-int-convert", "no-sys-f16-f128-convert"]
3842
# Some platforms have some f128 functions but everything except integer conversions
3943
no-sys-f128-int-convert = []
44+
no-sys-f16-f128-convert = []
45+
# Skip tests that rely on f16 symbols being available on the system
46+
no-sys-f16 = []
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[[bench]]
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name = "float_add"
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harness = false
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[[bench]]
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name = "float_sub"
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harness = false
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56+
[[bench]]
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name = "float_mul"
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harness = false
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[[bench]]
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name = "float_div"
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harness = false
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64+
[[bench]]
65+
name = "float_cmp"
66+
harness = false
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68+
[[bench]]
69+
name = "float_conv"
70+
harness = false
71+
72+
[[bench]]
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name = "float_extend"
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harness = false
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76+
[[bench]]
77+
name = "float_trunc"
78+
harness = false
79+
80+
[[bench]]
81+
name = "float_pow"
82+
harness = false

‎testcrate/benches/float_add.rs

+81
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,81 @@
1+
#![feature(f128)]
2+
3+
use compiler_builtins::float::add;
4+
use criterion::{criterion_group, criterion_main, Criterion};
5+
use testcrate::float_bench;
6+
7+
float_bench! {
8+
name: add_f32,
9+
sig: (a: f32, b: f32) -> f32,
10+
crate_fn: add::__addsf3,
11+
sys_fn: __addsf3,
12+
sys_available: all(),
13+
asm: [
14+
#[cfg(target_arch = "x86_64")] {
15+
asm!(
16+
"addss {a}, {b}",
17+
a = inout(xmm_reg) a,
18+
b = in(xmm_reg) b,
19+
options(nomem, nostack)
20+
);
21+
22+
a
23+
};
24+
25+
#[cfg(target_arch = "aarch64")] {
26+
asm!(
27+
"fadd {a:s}, {a:s}, {b:s}",
28+
a = inout(vreg) a,
29+
b = in(vreg) b,
30+
options(nomem, nostack)
31+
);
32+
33+
a
34+
};
35+
],
36+
}
37+
38+
float_bench! {
39+
name: add_f64,
40+
sig: (a: f64, b: f64) -> f64,
41+
crate_fn: add::__adddf3,
42+
sys_fn: __adddf3,
43+
sys_available: all(),
44+
asm: [
45+
#[cfg(target_arch = "x86_64")] {
46+
asm!(
47+
"addsd {a}, {b}",
48+
a = inout(xmm_reg) a,
49+
b = in(xmm_reg) b,
50+
options(nomem, nostack)
51+
);
52+
53+
a
54+
};
55+
56+
#[cfg(target_arch = "aarch64")] {
57+
asm!(
58+
"fadd {a:d}, {a:d}, {b:d}",
59+
a = inout(vreg) a,
60+
b = in(vreg) b,
61+
options(nomem, nostack)
62+
);
63+
64+
a
65+
};
66+
],
67+
}
68+
69+
float_bench! {
70+
name: add_f128,
71+
sig: (a: f128, b: f128) -> f128,
72+
crate_fn: add::__addtf3,
73+
crate_fn_ppc: add::__addkf3,
74+
sys_fn: __addtf3,
75+
sys_fn_ppc: __addkf3,
76+
sys_available: not(feature = "no-sys-f128"),
77+
asm: []
78+
}
79+
80+
criterion_group!(float_add, add_f32, add_f64, add_f128);
81+
criterion_main!(float_add);

‎testcrate/benches/float_cmp.rs

+202
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,202 @@
1+
#![feature(f128)]
2+
3+
use criterion::{criterion_group, criterion_main, Criterion};
4+
use testcrate::float_bench;
5+
6+
use compiler_builtins::float::cmp;
7+
8+
/// `gt` symbols are allowed to return differing results, they just get compared
9+
/// to 0.
10+
fn gt_res_eq(a: i32, b: i32) -> bool {
11+
let a_lt_0 = a <= 0;
12+
let b_lt_0 = b <= 0;
13+
(a_lt_0 && b_lt_0) || (!a_lt_0 && !b_lt_0)
14+
}
15+
16+
float_bench! {
17+
name: cmp_f32_gt,
18+
sig: (a: f32, b: f32) -> i32,
19+
crate_fn: cmp::__gtsf2,
20+
sys_fn: __gtsf2,
21+
sys_available: all(),
22+
output_eq: gt_res_eq,
23+
asm: [
24+
#[cfg(target_arch = "x86_64")] {
25+
let ret: i32;
26+
asm!(
27+
"xor {ret:e}, {ret:e}",
28+
"ucomiss {a}, {b}",
29+
"seta {ret:l}",
30+
a = in(xmm_reg) a,
31+
b = in(xmm_reg) b,
32+
ret = out(reg) ret,
33+
options(nomem, nostack)
34+
);
35+
36+
ret
37+
};
38+
39+
#[cfg(target_arch = "aarch64")] {
40+
let ret: i32;
41+
asm!(
42+
"fcmp {a:s}, {b:s}",
43+
"cset {ret:w}, gt",
44+
a = in(vreg) a,
45+
b = in(vreg) b,
46+
ret = out(reg) ret,
47+
options(nomem,nostack),
48+
);
49+
50+
ret
51+
};
52+
],
53+
}
54+
55+
float_bench! {
56+
name: cmp_f32_unord,
57+
sig: (a: f32, b: f32) -> i32,
58+
crate_fn: cmp::__unordsf2,
59+
sys_fn: __unordsf2,
60+
sys_available: all(),
61+
asm: [
62+
#[cfg(target_arch = "x86_64")] {
63+
let ret: i32;
64+
asm!(
65+
"xor {ret:e}, {ret:e}",
66+
"ucomiss {a}, {b}",
67+
"setp {ret:l}",
68+
a = in(xmm_reg) a,
69+
b = in(xmm_reg) b,
70+
ret = out(reg) ret,
71+
options(nomem, nostack)
72+
);
73+
74+
ret
75+
};
76+
77+
#[cfg(target_arch = "aarch64")] {
78+
let ret: i32;
79+
asm!(
80+
"fcmp {a:s}, {b:s}",
81+
"cset {ret:w}, vs",
82+
a = in(vreg) a,
83+
b = in(vreg) b,
84+
ret = out(reg) ret,
85+
options(nomem, nostack)
86+
);
87+
88+
ret
89+
};
90+
],
91+
}
92+
93+
float_bench! {
94+
name: cmp_f64_gt,
95+
sig: (a: f64, b: f64) -> i32,
96+
crate_fn: cmp::__gtdf2,
97+
sys_fn: __gtdf2,
98+
sys_available: all(),
99+
output_eq: gt_res_eq,
100+
asm: [
101+
#[cfg(target_arch = "x86_64")] {
102+
let ret: i32;
103+
asm!(
104+
"xor {ret:e}, {ret:e}",
105+
"ucomisd {a}, {b}",
106+
"seta {ret:l}",
107+
a = in(xmm_reg) a,
108+
b = in(xmm_reg) b,
109+
ret = out(reg) ret,
110+
options(nomem, nostack)
111+
);
112+
113+
ret
114+
};
115+
116+
#[cfg(target_arch = "aarch64")] {
117+
let ret: i32;
118+
asm!(
119+
"fcmp {a:d}, {b:d}",
120+
"cset {ret:w}, gt",
121+
a = in(vreg) a,
122+
b = in(vreg) b,
123+
ret = out(reg) ret,
124+
options(nomem, nostack)
125+
);
126+
127+
ret
128+
};
129+
],
130+
}
131+
132+
float_bench! {
133+
name: cmp_f64_unord,
134+
sig: (a: f64, b: f64) -> i32,
135+
crate_fn: cmp::__unorddf2,
136+
sys_fn: __unorddf2,
137+
sys_available: all(),
138+
asm: [
139+
#[cfg(target_arch = "x86_64")] {
140+
let ret: i32;
141+
asm!(
142+
"xor {ret:e}, {ret:e}",
143+
"ucomisd {a}, {b}",
144+
"setp {ret:l}",
145+
a = in(xmm_reg) a,
146+
b = in(xmm_reg) b,
147+
ret = out(reg) ret,
148+
options(nomem, nostack)
149+
);
150+
151+
ret
152+
};
153+
154+
#[cfg(target_arch = "aarch64")] {
155+
let ret: i32;
156+
asm!(
157+
"fcmp {a:d}, {b:d}",
158+
"cset {ret:w}, vs",
159+
a = in(vreg) a,
160+
b = in(vreg) b,
161+
ret = out(reg) ret,
162+
options(nomem, nostack)
163+
);
164+
165+
ret
166+
};
167+
],
168+
}
169+
170+
float_bench! {
171+
name: cmp_f128_gt,
172+
sig: (a: f128, b: f128) -> i32,
173+
crate_fn: cmp::__gttf2,
174+
crate_fn_ppc: cmp::__gtkf2,
175+
sys_fn: __gttf2,
176+
sys_fn_ppc: __gtkf2,
177+
sys_available: not(feature = "no-sys-f128"),
178+
output_eq: gt_res_eq,
179+
asm: []
180+
}
181+
182+
float_bench! {
183+
name: cmp_f128_unord,
184+
sig: (a: f128, b: f128) -> i32,
185+
crate_fn: cmp::__unordtf2,
186+
crate_fn_ppc: cmp::__unordkf2,
187+
sys_fn: __unordtf2,
188+
sys_fn_ppc: __unordkf2,
189+
sys_available: not(feature = "no-sys-f128"),
190+
asm: []
191+
}
192+
193+
criterion_group!(
194+
float_cmp,
195+
cmp_f32_gt,
196+
cmp_f32_unord,
197+
cmp_f64_gt,
198+
cmp_f64_unord,
199+
cmp_f128_gt,
200+
cmp_f128_unord
201+
);
202+
criterion_main!(float_cmp);

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