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20bd5e8018
`__addosi4`, `__addodi4`, `__addoti4`, `__subosi4`, `__subodi4`, and `__suboti4` were all functions which we invented for no apparent reason. Neither LLVM, nor GCC, nor the Zig compiler use these functions. It appears the functions were created in a kind of misunderstanding of an old language proposal; see https://github.com/ziglang/zig/pull/10824. There is no benefit to these functions existing; if a Zig compiler backend needs this operation, it is trivial to implement, and *far* simpler than calling a compiler-rt routine. Therefore, this commit deletes them. A small amount of that code was used by other parts of compiler-rt; the logic is trivial so has just been inlined where needed. I also chose to quickly implement `__addvdi3` (a standard function) because it is trivial and we already implement the `sub` parallel.
26 lines
983 B
Zig
26 lines
983 B
Zig
const common = @import("./common.zig");
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const testing = @import("std").testing;
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pub const panic = common.panic;
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comptime {
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@export(&__subvdi3, .{ .name = "__subvdi3", .linkage = common.linkage, .visibility = common.visibility });
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}
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pub fn __subvdi3(a: i64, b: i64) callconv(.c) i64 {
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const sum = a -% b;
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// Overflow occurred iff the operands have opposite signs, and the sign of the
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// sum is the opposite of the lhs sign.
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if (((a ^ b) & (sum ^ a)) < 0) @panic("compiler-rt: integer overflow");
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return sum;
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}
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test "subvdi3" {
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// min i64 = -9223372036854775808
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// max i64 = 9223372036854775807
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// TODO write panic handler for testing panics
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// try test__subvdi3(-9223372036854775808, -1, -1); // panic
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// try test__addvdi3(9223372036854775807, 1, 1); // panic
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try testing.expectEqual(-9223372036854775808, __subvdi3(-9223372036854775807, 1));
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try testing.expectEqual(9223372036854775807, __subvdi3(9223372036854775806, -1));
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}
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