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c9e67e71c1
The old isARM() function was a portability trap. With the name it had, it seemed like the obviously correct function to use, but it didn't include Thumb. In the vast majority of cases where someone wants to ask "is the target Arm?", Thumb *should* be included. There are exactly 3 cases in the codebase where we do actually need to exclude Thumb, although one of those is in Aro and mirrors a check in Clang that is itself likely a bug. These rare cases can just add an extra isThumb() check.
46 lines
1.6 KiB
Zig
46 lines
1.6 KiB
Zig
const std = @import("../std.zig");
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const builtin = @import("builtin");
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const math = std.math;
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const meta = std.meta;
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const expect = std.testing.expect;
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pub fn isNan(x: anytype) bool {
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return x != x;
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}
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/// TODO: LLVM is known to miscompile on some architectures to quiet NaN -
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/// this is tracked by https://github.com/ziglang/zig/issues/14366
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pub fn isSignalNan(x: anytype) bool {
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const T = @TypeOf(x);
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const U = meta.Int(.unsigned, @bitSizeOf(T));
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const quiet_signal_bit_mask = 1 << (math.floatFractionalBits(T) - 1);
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return isNan(x) and (@as(U, @bitCast(x)) & quiet_signal_bit_mask == 0);
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}
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test isNan {
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inline for ([_]type{ f16, f32, f64, f80, f128, c_longdouble }) |T| {
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try expect(isNan(math.nan(T)));
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try expect(isNan(-math.nan(T)));
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try expect(isNan(math.snan(T)));
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try expect(!isNan(@as(T, 1.0)));
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try expect(!isNan(@as(T, math.inf(T))));
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}
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}
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test isSignalNan {
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inline for ([_]type{ f16, f32, f64, f80, f128, c_longdouble }) |T| {
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// TODO: Signalling NaN values get converted to quiet NaN values in
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// some cases where they shouldn't such that this can fail.
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// See https://github.com/ziglang/zig/issues/14366
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if (!builtin.cpu.arch.isArm() and
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!builtin.cpu.arch.isAARCH64() and
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!builtin.cpu.arch.isPowerPC() and
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builtin.zig_backend != .stage2_c)
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{
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try expect(isSignalNan(math.snan(T)));
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}
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try expect(!isSignalNan(math.nan(T)));
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try expect(!isSignalNan(@as(T, 1.0)));
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try expect(!isSignalNan(math.inf(T)));
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}
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}
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