authorgravatar for jan.hafer@rwth-aachen.deJan Philipp Hafer <jan.hafer@rwth-aachen.de> 2021-12-12 22:25:29+01:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2021-12-27 14:35:45-08:00
log17046674a745faaa34cf2646b9cf43455b12aba9
tree0826d357cbfedea2e0b5309b1316b2ea731d1dbf
parent70894d5c2f6032b0d0be1fa00a30554b7e6db2d6

compiler_rt: add __negvsi2, __negvdi2, __negvti2

- neg can only overflow, if a == MIN - case `-0` is properly handled by hardware, so overflow check by comparing `a == MIN` is sufficient - tests: MIN, MIN+1, MIN+4, -42, -7, -1, 0, 1, 7.. See #1290

6 files changed, 128 insertions(+), 0 deletions(-)

CMakeLists.txt+1
...@@ -500,6 +500,7 @@ set(ZIG_STAGE2_SOURCES...@@ -500,6 +500,7 @@ set(ZIG_STAGE2_SOURCES
500 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/multi3.zig"500 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/multi3.zig"
501 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negXf2.zig"501 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negXf2.zig"
502 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negXi2.zig"502 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negXi2.zig"
503 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negv.zig"
503 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/os_version_check.zig"504 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/os_version_check.zig"
504 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/parity.zig"505 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/parity.zig"
505 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/popcount.zig"506 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/popcount.zig"
lib/std/special/compiler_rt.zig+6
...@@ -423,6 +423,12 @@ comptime {...@@ -423,6 +423,12 @@ comptime {
423 @export(__absvdi2, .{ .name = "__absvdi2", .linkage = linkage });423 @export(__absvdi2, .{ .name = "__absvdi2", .linkage = linkage });
424 const __absvti2 = @import("compiler_rt/absv.zig").__absvti2;424 const __absvti2 = @import("compiler_rt/absv.zig").__absvti2;
425 @export(__absvti2, .{ .name = "__absvti2", .linkage = linkage });425 @export(__absvti2, .{ .name = "__absvti2", .linkage = linkage });
426 const __negvsi2 = @import("compiler_rt/negv.zig").__negvsi2;
427 @export(__negvsi2, .{ .name = "__negvsi2", .linkage = linkage });
428 const __negvdi2 = @import("compiler_rt/negv.zig").__negvdi2;
429 @export(__negvdi2, .{ .name = "__negvdi2", .linkage = linkage });
430 const __negvti2 = @import("compiler_rt/negv.zig").__negvti2;
431 @export(__negvti2, .{ .name = "__negvti2", .linkage = linkage });
426432
427 // missing: Integral arithmetic which returns if overflow433 // missing: Integral arithmetic which returns if overflow
428434
lib/std/special/compiler_rt/negv.zig created+31
...@@ -0,0 +1,31 @@
1// negv - negate oVerflow
2// * @panic, if result can not be represented
3// - negvXi4_generic for unoptimized version
4
5// assume -0 == 0 is gracefully handled by the hardware
6fn negvXi_generic(comptime ST: type) fn (a: ST) callconv(.C) ST {
7 return struct {
8 fn f(a: ST) callconv(.C) ST {
9 const UT = switch (ST) {
10 i32 => u32,
11 i64 => u64,
12 i128 => u128,
13 else => unreachable,
14 };
15 const N: UT = @bitSizeOf(ST);
16 const min: ST = @bitCast(ST, (@as(UT, 1) << (N - 1)));
17 if (a == min)
18 @panic("compiler_rt negv: overflow");
19 return -a;
20 }
21 }.f;
22}
23pub const __negvsi2 = negvXi_generic(i32);
24pub const __negvdi2 = negvXi_generic(i64);
25pub const __negvti2 = negvXi_generic(i128);
26
27test {
28 _ = @import("negvsi2_test.zig");
29 _ = @import("negvdi2_test.zig");
30 _ = @import("negvti2_test.zig");
31}
lib/std/special/compiler_rt/negvdi2_test.zig created+30
...@@ -0,0 +1,30 @@
1const negv = @import("negv.zig");
2const testing = @import("std").testing;
3
4fn test__negvdi2(a: i64, expected: i64) !void {
5 var result = negv.__negvdi2(a);
6 try testing.expectEqual(expected, result);
7}
8
9test "negvdi2" {
10 // -2^63 <= i64 <= 2^63-1
11 // 2^63 = 9223372036854775808
12 // 2^63-1 = 9223372036854775807
13 // TODO write panic handler for testing panics
14 //try test__negvdi2(-9223372036854775808, -5); // tested with return -5; and panic
15 try test__negvdi2(-9223372036854775807, 9223372036854775807);
16 try test__negvdi2(-9223372036854775806, 9223372036854775806);
17 try test__negvdi2(-9223372036854775805, 9223372036854775805);
18 try test__negvdi2(-9223372036854775804, 9223372036854775804);
19 try test__negvdi2(-42, 42);
20 try test__negvdi2(-7, 7);
21 try test__negvdi2(-1, 1);
22 try test__negvdi2(0, 0);
23 try test__negvdi2(1, -1);
24 try test__negvdi2(7, -7);
25 try test__negvdi2(42, -42);
26 try test__negvdi2(9223372036854775804, -9223372036854775804);
27 try test__negvdi2(9223372036854775805, -9223372036854775805);
28 try test__negvdi2(9223372036854775806, -9223372036854775806);
29 try test__negvdi2(9223372036854775807, -9223372036854775807);
30}
lib/std/special/compiler_rt/negvsi2_test.zig created+30
...@@ -0,0 +1,30 @@
1const negv = @import("negv.zig");
2const testing = @import("std").testing;
3
4fn test__negvsi2(a: i32, expected: i32) !void {
5 var result = negv.__negvsi2(a);
6 try testing.expectEqual(expected, result);
7}
8
9test "negvsi2" {
10 // -2^31 <= i32 <= 2^31-1
11 // 2^31 = 2147483648
12 // 2^31-1 = 2147483647
13 // TODO write panic handler for testing panics
14 //try test__negvsi2(-2147483648, -5); // tested with return -5; and panic
15 try test__negvsi2(-2147483647, 2147483647);
16 try test__negvsi2(-2147483646, 2147483646);
17 try test__negvsi2(-2147483645, 2147483645);
18 try test__negvsi2(-2147483644, 2147483644);
19 try test__negvsi2(-42, 42);
20 try test__negvsi2(-7, 7);
21 try test__negvsi2(-1, 1);
22 try test__negvsi2(0, 0);
23 try test__negvsi2(1, -1);
24 try test__negvsi2(7, -7);
25 try test__negvsi2(42, -42);
26 try test__negvsi2(2147483644, -2147483644);
27 try test__negvsi2(2147483645, -2147483645);
28 try test__negvsi2(2147483646, -2147483646);
29 try test__negvsi2(2147483647, -2147483647);
30}
lib/std/special/compiler_rt/negvti2_test.zig created+30
...@@ -0,0 +1,30 @@
1const negv = @import("negv.zig");
2const testing = @import("std").testing;
3
4fn test__negvti2(a: i128, expected: i128) !void {
5 var result = negv.__negvti2(a);
6 try testing.expectEqual(expected, result);
7}
8
9test "negvti2" {
10 // -2^127 <= i128 <= 2^127-1
11 // 2^127 = 170141183460469231731687303715884105728
12 // 2^127+1 = 170141183460469231731687303715884105727
13 // TODO write panic handler for testing panics
14 //try test__negvti2(-170141183460469231731687303715884105728, -5); // tested with return -5; and panic
15 try test__negvti2(-170141183460469231731687303715884105727, 170141183460469231731687303715884105727);
16 try test__negvti2(-170141183460469231731687303715884105726, 170141183460469231731687303715884105726);
17 try test__negvti2(-170141183460469231731687303715884105725, 170141183460469231731687303715884105725);
18 try test__negvti2(-170141183460469231731687303715884105724, 170141183460469231731687303715884105724);
19 try test__negvti2(-42, 42);
20 try test__negvti2(-7, 7);
21 try test__negvti2(-1, 1);
22 try test__negvti2(0, 0);
23 try test__negvti2(1, -1);
24 try test__negvti2(7, -7);
25 try test__negvti2(42, -42);
26 try test__negvti2(170141183460469231731687303715884105724, -170141183460469231731687303715884105724);
27 try test__negvti2(170141183460469231731687303715884105725, -170141183460469231731687303715884105725);
28 try test__negvti2(170141183460469231731687303715884105726, -170141183460469231731687303715884105726);
29 try test__negvti2(170141183460469231731687303715884105727, -170141183460469231731687303715884105727);
30}