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compiler_rt: refactor __mulodi2 and __muloti2 to get __mulosi2

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- use comptime instead of 2 identical implementations
- tests: port missing tests and link to archived llvm-mirror release 80

See #1290
This commit is contained in:
Jan Philipp Hafer 2021-12-12 00:27:41 +01:00 committed by Andrew Kelley
parent 93c6ab4952
commit eb1e75b2b8
9 changed files with 166 additions and 101 deletions
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3
CMakeLists.txt
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@ -494,8 +494,7 @@ set(ZIG_STAGE2_SOURCES
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/modti3.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/mulXf3.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/muldi3.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/mulodi4.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/muloti4.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/mulo.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/multi3.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negXf2.zig"
"${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/negXi2.zig"

6
lib/std/special/compiler_rt.zig
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@ -77,9 +77,11 @@ comptime {
@export(__extendhfsf2, .{ .name = "__gnu_h2f_ieee", .linkage = linkage });
// Integral arithmetic which returns if overflow
const __mulodi4 = @import("compiler_rt/mulodi4.zig").__mulodi4;
const __mulosi4 = @import("compiler_rt/mulo.zig").__mulosi4;
@export(__mulosi4, .{ .name = "__mulosi4", .linkage = linkage });
const __mulodi4 = @import("compiler_rt/mulo.zig").__mulodi4;
@export(__mulodi4, .{ .name = "__mulodi4", .linkage = linkage });
const __muloti4 = @import("compiler_rt/muloti4.zig").__muloti4;
const __muloti4 = @import("compiler_rt/mulo.zig").__muloti4;
@export(__muloti4, .{ .name = "__muloti4", .linkage = linkage });
}

1
lib/std/special/compiler_rt/bswap.zig
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@ -6,7 +6,6 @@ const builtin = @import("builtin");
// ie for u32
// DE AD BE EF <- little|big endian
// FE BE AD DE <- big|little endian
// ie for u32
// ff 00 00 00 >> 3*8 (leftmost byte)
// 00 ff 00 00 >> 1*8 (2nd left byte)
// 00 00 ff 00 << 1*8 (2n right byte)

69
lib/std/special/compiler_rt/mulo.zig Normal file
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@ -0,0 +1,69 @@
const builtin = @import("builtin");
// mulo - multiplication overflow
// - muloXi4_generic for unoptimized version
// return a*b.
// return if a*b overflows => 1 else => 0
// see https://stackoverflow.com/a/26320664 for possible implementations
fn muloXi4_generic(comptime ST: type) fn (a: ST, b: ST, overflow: *c_int) callconv(.C) ST {
return struct {
fn f(a: ST, b: ST, overflow: *c_int) callconv(.C) ST {
@setRuntimeSafety(builtin.is_test);
const BSIZE = @bitSizeOf(ST);
comptime var UT = switch (ST) {
i32 => u32,
i64 => u64,
i128 => u128,
else => unreachable,
};
const min = @bitCast(ST, @as(UT, 1 << (BSIZE - 1)));
const max = ~min;
overflow.* = 0;
const result = a *% b;
// edge cases
if (a == min) {
if (b != 0 and b != 1) overflow.* = 1;
return result;
}
if (b == min) {
if (a != 0 and a != 1) overflow.* = 1;
return result;
}
// take sign of x sx
const sa = a >> (BSIZE - 1);
const sb = b >> (BSIZE - 1);
// take absolute value of a and b via
// abs(x) = (x^sx)) - sx
const abs_a = (a ^ sa) -% sa;
const abs_b = (b ^ sb) -% sb;
// unitary magnitude, cannot have overflow
if (abs_a < 2 or abs_b < 2) return result;
// compare the signs of operands
if ((a ^ b) >> (BSIZE - 1) != 0) {
if (abs_a > @divTrunc(max, abs_b)) overflow.* = 1;
} else {
if (abs_a > @divTrunc(min, -abs_b)) overflow.* = 1;
}
return result;
}
}.f;
}
pub const __mulosi4 = muloXi4_generic(i32);
pub const __mulodi4 = muloXi4_generic(i64);
pub const __muloti4 = muloXi4_generic(i128);
test {
_ = @import("mulosi4_test.zig");
_ = @import("mulodi4_test.zig");
_ = @import("muloti4_test.zig");
}

42
lib/std/special/compiler_rt/mulodi4.zig
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@ -1,42 +0,0 @@
const builtin = @import("builtin");
const compiler_rt = @import("../compiler_rt.zig");
pub fn __mulodi4(a: i64, b: i64, overflow: *c_int) callconv(.C) i64 {
@setRuntimeSafety(builtin.is_test);
const min = @bitCast(i64, @as(u64, 1 << (64 - 1)));
const max = ~min;
overflow.* = 0;
const result = a *% b;
// Edge cases
if (a == min) {
if (b != 0 and b != 1) overflow.* = 1;
return result;
}
if (b == min) {
if (a != 0 and a != 1) overflow.* = 1;
return result;
}
// Take absolute value of a and b via abs(x) = (x^(x >> 63)) - (x >> 63).
const abs_a = (a ^ (a >> 63)) -% (a >> 63);
const abs_b = (b ^ (b >> 63)) -% (b >> 63);
// Unitary magnitude, cannot have overflow
if (abs_a < 2 or abs_b < 2) return result;
// Compare the signs of the operands
if ((a ^ b) >> 63 != 0) {
if (abs_a > @divTrunc(max, abs_b)) overflow.* = 1;
} else {
if (abs_a > @divTrunc(min, -abs_b)) overflow.* = 1;
}
return result;
}
test {
_ = @import("mulodi4_test.zig");
}

6
lib/std/special/compiler_rt/mulodi4_test.zig
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@ -1,9 +1,11 @@
const __mulodi4 = @import("mulodi4.zig").__mulodi4;
const mulo = @import("mulo.zig");
const testing = @import("std").testing;
// ported from https://github.com/llvm-mirror/compiler-rt/tree/release_80/test/builtins/Unit
fn test__mulodi4(a: i64, b: i64, expected: i64, expected_overflow: c_int) !void {
var overflow: c_int = undefined;
const x = __mulodi4(a, b, &overflow);
const x = mulo.__mulodi4(a, b, &overflow);
try testing.expect(overflow == expected_overflow and (expected_overflow != 0 or x == expected));
}

72
lib/std/special/compiler_rt/mulosi4_test.zig Normal file
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@ -0,0 +1,72 @@
const mulo = @import("mulo.zig");
const testing = @import("std").testing;
// ported from https://github.com/llvm-mirror/compiler-rt/tree/release_80/test/builtins/Unit
fn test__mulosi4(a: i32, b: i32, expected: i32, expected_overflow: c_int) !void {
var overflow: c_int = undefined;
const x = mulo.__mulosi4(a, b, &overflow);
try testing.expect(overflow == expected_overflow and (expected_overflow != 0 or x == expected));
}
test "mulosi4" {
try test__mulosi4(0, 0, 0, 0);
try test__mulosi4(0, 1, 0, 0);
try test__mulosi4(1, 0, 0, 0);
try test__mulosi4(0, 10, 0, 0);
try test__mulosi4(10, 0, 0, 0);
try test__mulosi4(0, 0x1234567, 0, 0);
try test__mulosi4(0x1234567, 0, 0, 0);
try test__mulosi4(0, -1, 0, 0);
try test__mulosi4(-1, 0, 0, 0);
try test__mulosi4(0, -10, 0, 0);
try test__mulosi4(-10, 0, 0, 0);
try test__mulosi4(0, -0x1234567, 0, 0);
try test__mulosi4(-0x1234567, 0, 0, 0);
try test__mulosi4(1, 1, 1, 0);
try test__mulosi4(1, 10, 10, 0);
try test__mulosi4(10, 1, 10, 0);
try test__mulosi4(1, 0x1234567, 0x1234567, 0);
try test__mulosi4(0x1234567, 1, 0x1234567, 0);
try test__mulosi4(1, -1, -1, 0);
try test__mulosi4(1, -10, -10, 0);
try test__mulosi4(-10, 1, -10, 0);
try test__mulosi4(1, -0x1234567, -0x1234567, 0);
try test__mulosi4(-0x1234567, 1, -0x1234567, 0);
try test__mulosi4(0x7FFFFFFF, -2, @bitCast(i32, @as(u32, 0x80000001)), 1);
try test__mulosi4(-2, 0x7FFFFFFF, @bitCast(i32, @as(u32, 0x80000001)), 1);
try test__mulosi4(0x7FFFFFFF, -1, @bitCast(i32, @as(u32, 0x80000001)), 0);
try test__mulosi4(-1, 0x7FFFFFFF, @bitCast(i32, @as(u32, 0x80000001)), 0);
try test__mulosi4(0x7FFFFFFF, 0, 0, 0);
try test__mulosi4(0, 0x7FFFFFFF, 0, 0);
try test__mulosi4(0x7FFFFFFF, 1, 0x7FFFFFFF, 0);
try test__mulosi4(1, 0x7FFFFFFF, 0x7FFFFFFF, 0);
try test__mulosi4(0x7FFFFFFF, 2, @bitCast(i32, @as(u32, 0x80000001)), 1);
try test__mulosi4(2, 0x7FFFFFFF, @bitCast(i32, @as(u32, 0x80000001)), 1);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000000)), -2, @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(-2, @bitCast(i32, @as(u32, 0x80000000)), @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000000)), -1, @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(-1, @bitCast(i32, @as(u32, 0x80000000)), @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000000)), 0, 0, 0);
try test__mulosi4(0, @bitCast(i32, @as(u32, 0x80000000)), 0, 0);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000000)), 1, @bitCast(i32, @as(u32, 0x80000000)), 0);
try test__mulosi4(1, @bitCast(i32, @as(u32, 0x80000000)), @bitCast(i32, @as(u32, 0x80000000)), 0);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000000)), 2, @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(2, @bitCast(i32, @as(u32, 0x80000000)), @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000001)), -2, @bitCast(i32, @as(u32, 0x80000001)), 1);
try test__mulosi4(-2, @bitCast(i32, @as(u32, 0x80000001)), @bitCast(i32, @as(u32, 0x80000001)), 1);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000001)), -1, 0x7FFFFFFF, 0);
try test__mulosi4(-1, @bitCast(i32, @as(u32, 0x80000001)), 0x7FFFFFFF, 0);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000001)), 0, 0, 0);
try test__mulosi4(0, @bitCast(i32, @as(u32, 0x80000001)), 0, 0);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000001)), 1, @bitCast(i32, @as(u32, 0x80000001)), 0);
try test__mulosi4(1, @bitCast(i32, @as(u32, 0x80000001)), @bitCast(i32, @as(u32, 0x80000001)), 0);
try test__mulosi4(@bitCast(i32, @as(u32, 0x80000001)), 2, @bitCast(i32, @as(u32, 0x80000000)), 1);
try test__mulosi4(2, @bitCast(i32, @as(u32, 0x80000001)), @bitCast(i32, @as(u32, 0x80000000)), 1);
}

49
lib/std/special/compiler_rt/muloti4.zig
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@ -1,49 +0,0 @@
const builtin = @import("builtin");
const compiler_rt = @import("../compiler_rt.zig");
pub fn __muloti4(a: i128, b: i128, overflow: *c_int) callconv(.C) i128 {
@setRuntimeSafety(builtin.is_test);
const min = @bitCast(i128, @as(u128, 1 << (128 - 1)));
const max = ~min;
overflow.* = 0;
const r = a *% b;
if (a == min) {
if (b != 0 and b != 1) {
overflow.* = 1;
}
return r;
}
if (b == min) {
if (a != 0 and a != 1) {
overflow.* = 1;
}
return r;
}
const sa = a >> (128 - 1);
const abs_a = (a ^ sa) -% sa;
const sb = b >> (128 - 1);
const abs_b = (b ^ sb) -% sb;
if (abs_a < 2 or abs_b < 2) {
return r;
}
if (sa == sb) {
if (abs_a > @divTrunc(max, abs_b)) {
overflow.* = 1;
}
} else {
if (abs_a > @divTrunc(min, -abs_b)) {
overflow.* = 1;
}
}
return r;
}
test {
_ = @import("muloti4_test.zig");
}

19
lib/std/special/compiler_rt/muloti4_test.zig
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@ -1,9 +1,11 @@
const __muloti4 = @import("muloti4.zig").__muloti4;
const mulo = @import("mulo.zig");
const testing = @import("std").testing;
// ported from https://github.com/llvm-mirror/compiler-rt/tree/release_80/test/builtins/Unit
fn test__muloti4(a: i128, b: i128, expected: i128, expected_overflow: c_int) !void {
var overflow: c_int = undefined;
const x = __muloti4(a, b, &overflow);
const x = mulo.__muloti4(a, b, &overflow);
try testing.expect(overflow == expected_overflow and (expected_overflow != 0 or x == expected));
}
@ -13,7 +15,6 @@ test "muloti4" {
try test__muloti4(1, 0, 0, 0);
try test__muloti4(0, 10, 0, 0);
try test__muloti4(10, 0, 0, 0);
try test__muloti4(0, 81985529216486895, 0, 0);
try test__muloti4(81985529216486895, 0, 0, 0);
@ -24,6 +25,18 @@ test "muloti4" {
try test__muloti4(0, -81985529216486895, 0, 0);
try test__muloti4(-81985529216486895, 0, 0, 0);
try test__muloti4(1, 1, 1, 0);
try test__muloti4(1, 10, 10, 0);
try test__muloti4(10, 1, 10, 0);
try test__muloti4(1, 81985529216486895, 81985529216486895, 0);
try test__muloti4(81985529216486895, 1, 81985529216486895, 0);
try test__muloti4(1, -1, -1, 0);
try test__muloti4(1, -10, -10, 0);
try test__muloti4(-10, 1, -10, 0);
try test__muloti4(1, -81985529216486895, -81985529216486895, 0);
try test__muloti4(-81985529216486895, 1, -81985529216486895, 0);
try test__muloti4(3037000499, 3037000499, 9223372030926249001, 0);
try test__muloti4(-3037000499, 3037000499, -9223372030926249001, 0);
try test__muloti4(3037000499, -3037000499, -9223372030926249001, 0);