compiler_rt: add __cmpXi2 and __ucmpXi2

- adds __cmpsi2, __cmpdi2, __cmpti2
- adds __ucmpsi2, __ucmpdi2, __ucmpti2
- use 2 if statements with 2 temporaries and a constant
- tests: MIN, MIN+1, MIN/2, -1, 0, 1, MAX/2, MAX-1, MAX if applicable

See ziglang#1290

CMakeLists.txt

@@ -448,6 +448,7 @@ set(ZIG_STAGE2_SOURCES
     "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/atomics.zig"
     "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/bswap.zig"
     "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/clear_cache.zig"
+    "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/cmp.zig"
     "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/compareXf2.zig"
     "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/count0bits.zig"
     "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/divdf3.zig"

lib/std/special/compiler_rt.zig

@@ -413,10 +413,22 @@ comptime {
 
         // missing: Integral arithmetic which returns if overflow
 
-        // missing: Integral comparison
+        // Integral comparison
         // (a <  b) => 0
         // (a == b) => 1
         // (a >  b) => 2
+        const __cmpsi2 = @import("compiler_rt/cmp.zig").__cmpsi2;
+        @export(__cmpsi2, .{ .name = "__cmpsi2", .linkage = linkage });
+        const __cmpdi2 = @import("compiler_rt/cmp.zig").__cmpdi2;
+        @export(__cmpdi2, .{ .name = "__cmpdi2", .linkage = linkage });
+        const __cmpti2 = @import("compiler_rt/cmp.zig").__cmpti2;
+        @export(__cmpti2, .{ .name = "__cmpti2", .linkage = linkage });
+        const __ucmpsi2 = @import("compiler_rt/cmp.zig").__ucmpsi2;
+        @export(__ucmpsi2, .{ .name = "__ucmpsi2", .linkage = linkage });
+        const __ucmpdi2 = @import("compiler_rt/cmp.zig").__ucmpdi2;
+        @export(__ucmpdi2, .{ .name = "__ucmpdi2", .linkage = linkage });
+        const __ucmpti2 = @import("compiler_rt/cmp.zig").__ucmpti2;
+        @export(__ucmpti2, .{ .name = "__ucmpti2", .linkage = linkage });
 
         // missing: Floating point raised to integer power
 

lib/std/special/compiler_rt/cmp.zig

@@ -0,0 +1,45 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+// cmp - signed compare
+// - cmpXi2_generic for unoptimized little and big endian
+
+// ucmp - unsigned compare
+// - ucmpXi2_generic for unoptimized little and big endian
+
+// a <  b => 0
+// a == b => 1
+// a >  b => 2
+
+fn XcmpXi2_generic(comptime T: type) fn (a: T, b: T) callconv(.C) i32 {
+    return struct {
+        fn f(a: T, b: T) callconv(.C) i32 {
+            @setRuntimeSafety(builtin.is_test);
+            var cmp1: i32 = 0;
+            var cmp2: i32 = 0;
+            if (a > b)
+                cmp1 = 1;
+            if (a < b)
+                cmp2 = 1;
+            return cmp1 - cmp2 + 1;
+        }
+    }.f;
+}
+
+pub const __cmpsi2 = XcmpXi2_generic(i32);
+pub const __cmpdi2 = XcmpXi2_generic(i64);
+pub const __cmpti2 = XcmpXi2_generic(i128);
+
+pub const __ucmpsi2 = XcmpXi2_generic(u32);
+pub const __ucmpdi2 = XcmpXi2_generic(u64);
+pub const __ucmpti2 = XcmpXi2_generic(u128);
+
+test {
+    _ = @import("cmpsi2_test.zig");
+    _ = @import("cmpdi2_test.zig");
+    _ = @import("cmpti2_test.zig");
+
+    _ = @import("ucmpsi2_test.zig");
+    _ = @import("ucmpdi2_test.zig");
+    _ = @import("ucmpti2_test.zig");
+}

lib/std/special/compiler_rt/cmpdi2_test.zig

@@ -0,0 +1,105 @@
+const cmp = @import("cmp.zig");
+const testing = @import("std").testing;
+
+fn test__cmpdi2(a: i64, b: i64, expected: i64) !void {
+    var result = cmp.__cmpdi2(a, b);
+    try testing.expectEqual(expected, result);
+}
+
+test "cmpdi2" {
+    // minInt == -9223372036854775808
+    // maxInt == 9223372036854775807
+    // minInt/2 == -4611686018427387904
+    // maxInt/2 == 4611686018427387903
+    // 1. equality minInt, minInt+1, minInt/2, 0, maxInt/2, maxInt-1, maxInt
+    try test__cmpdi2(-9223372036854775808, -9223372036854775808, 1);
+    try test__cmpdi2(-9223372036854775807, -9223372036854775807, 1);
+    try test__cmpdi2(-4611686018427387904, -4611686018427387904, 1);
+    try test__cmpdi2(-1, -1, 1);
+    try test__cmpdi2(0, 0, 1);
+    try test__cmpdi2(1, 1, 1);
+    try test__cmpdi2(4611686018427387903, 4611686018427387903, 1);
+    try test__cmpdi2(9223372036854775806, 9223372036854775806, 1);
+    try test__cmpdi2(9223372036854775807, 9223372036854775807, 1);
+    // 2. cmp minInt,   {        minInt + 1, minInt/2, -1, 0, 1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpdi2(-9223372036854775808, -9223372036854775807, 0);
+    try test__cmpdi2(-9223372036854775808, -4611686018427387904, 0);
+    try test__cmpdi2(-9223372036854775808, -1, 0);
+    try test__cmpdi2(-9223372036854775808, 0, 0);
+    try test__cmpdi2(-9223372036854775808, 1, 0);
+    try test__cmpdi2(-9223372036854775808, 4611686018427387903, 0);
+    try test__cmpdi2(-9223372036854775808, 9223372036854775806, 0);
+    try test__cmpdi2(-9223372036854775808, 9223372036854775807, 0);
+    // 3. cmp minInt+1, {minInt,             minInt/2, -1,0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpdi2(-9223372036854775807, -9223372036854775808, 2);
+    try test__cmpdi2(-9223372036854775807, -4611686018427387904, 0);
+    try test__cmpdi2(-9223372036854775807, -1, 0);
+    try test__cmpdi2(-9223372036854775807, 0, 0);
+    try test__cmpdi2(-9223372036854775807, 1, 0);
+    try test__cmpdi2(-9223372036854775807, 4611686018427387903, 0);
+    try test__cmpdi2(-9223372036854775807, 9223372036854775806, 0);
+    try test__cmpdi2(-9223372036854775807, 9223372036854775807, 0);
+    // 4. cmp minInt/2, {minInt, minInt + 1,           -1,0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpdi2(-4611686018427387904, -9223372036854775808, 2);
+    try test__cmpdi2(-4611686018427387904, -9223372036854775807, 2);
+    try test__cmpdi2(-4611686018427387904, -1, 0);
+    try test__cmpdi2(-4611686018427387904, 0, 0);
+    try test__cmpdi2(-4611686018427387904, 1, 0);
+    try test__cmpdi2(-4611686018427387904, 4611686018427387903, 0);
+    try test__cmpdi2(-4611686018427387904, 9223372036854775806, 0);
+    try test__cmpdi2(-4611686018427387904, 9223372036854775807, 0);
+    // 5. cmp -1,       {minInt, minInt + 1, minInt/2,    0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpdi2(-1, -9223372036854775808, 2);
+    try test__cmpdi2(-1, -9223372036854775807, 2);
+    try test__cmpdi2(-1, -4611686018427387904, 2);
+    try test__cmpdi2(-1, 0, 0);
+    try test__cmpdi2(-1, 1, 0);
+    try test__cmpdi2(-1, 4611686018427387903, 0);
+    try test__cmpdi2(-1, 9223372036854775806, 0);
+    try test__cmpdi2(-1, 9223372036854775807, 0);
+    // 6. cmp 0,        {minInt, minInt + 1, minInt/2, -1,  1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpdi2(0, -9223372036854775808, 2);
+    try test__cmpdi2(0, -9223372036854775807, 2);
+    try test__cmpdi2(0, -4611686018427387904, 2);
+    try test__cmpdi2(0, -1, 2);
+    try test__cmpdi2(0, 1, 0);
+    try test__cmpdi2(0, 4611686018427387903, 0);
+    try test__cmpdi2(0, 9223372036854775806, 0);
+    try test__cmpdi2(0, 9223372036854775807, 0);
+    // 7. cmp 1,        {minInt, minInt + 1, minInt/2, -1,0,  maxInt/2, maxInt-1, maxInt}
+    try test__cmpdi2(1, -9223372036854775808, 2);
+    try test__cmpdi2(1, -9223372036854775807, 2);
+    try test__cmpdi2(1, -4611686018427387904, 2);
+    try test__cmpdi2(1, -1, 2);
+    try test__cmpdi2(1, 0, 2);
+    try test__cmpdi2(1, 4611686018427387903, 0);
+    try test__cmpdi2(1, 9223372036854775806, 0);
+    try test__cmpdi2(1, 9223372036854775807, 0);
+    // 8. cmp maxInt/2, {minInt, minInt + 1, minInt/2, -1,0,1,           maxInt-1, maxInt}
+    try test__cmpdi2(4611686018427387903, -9223372036854775808, 2);
+    try test__cmpdi2(4611686018427387903, -9223372036854775807, 2);
+    try test__cmpdi2(4611686018427387903, -4611686018427387904, 2);
+    try test__cmpdi2(4611686018427387903, -1, 2);
+    try test__cmpdi2(4611686018427387903, 0, 2);
+    try test__cmpdi2(4611686018427387903, 1, 2);
+    try test__cmpdi2(4611686018427387903, 9223372036854775806, 0);
+    try test__cmpdi2(4611686018427387903, 9223372036854775807, 0);
+    // 9. cmp maxInt-1, {minInt, minInt + 1, minInt/2, -1,0,1, maxInt/2,           maxInt}
+    try test__cmpdi2(9223372036854775806, -9223372036854775808, 2);
+    try test__cmpdi2(9223372036854775806, -9223372036854775807, 2);
+    try test__cmpdi2(9223372036854775806, -4611686018427387904, 2);
+    try test__cmpdi2(9223372036854775806, -1, 2);
+    try test__cmpdi2(9223372036854775806, 0, 2);
+    try test__cmpdi2(9223372036854775806, 1, 2);
+    try test__cmpdi2(9223372036854775806, 4611686018427387903, 2);
+    try test__cmpdi2(9223372036854775806, 9223372036854775807, 0);
+    // 10.cmp maxInt,   {minInt, minInt + 1, minInt/2, -1,0,1, maxInt/2, maxInt-1,       }
+    try test__cmpdi2(9223372036854775807, -9223372036854775808, 2);
+    try test__cmpdi2(9223372036854775807, -9223372036854775807, 2);
+    try test__cmpdi2(9223372036854775807, -4611686018427387904, 2);
+    try test__cmpdi2(9223372036854775807, -1, 2);
+    try test__cmpdi2(9223372036854775807, 0, 2);
+    try test__cmpdi2(9223372036854775807, 1, 2);
+    try test__cmpdi2(9223372036854775807, 4611686018427387903, 2);
+    try test__cmpdi2(9223372036854775807, 9223372036854775806, 2);
+}

lib/std/special/compiler_rt/cmpsi2_test.zig

@@ -0,0 +1,105 @@
+const cmp = @import("cmp.zig");
+const testing = @import("std").testing;
+
+fn test__cmpsi2(a: i32, b: i32, expected: i32) !void {
+    var result = cmp.__cmpsi2(a, b);
+    try testing.expectEqual(expected, result);
+}
+
+test "cmpsi2" {
+    // minInt == -2147483648
+    // maxInt == 2147483647
+    // minInt/2 == -1073741824
+    // maxInt/2 == 1073741823
+    // 1. equality minInt, minInt+1, minInt/2, -1, 0, 1, maxInt/2, maxInt-1, maxInt
+    try test__cmpsi2(-2147483648, -2147483648, 1);
+    try test__cmpsi2(-2147483647, -2147483647, 1);
+    try test__cmpsi2(-1073741824, -1073741824, 1);
+    try test__cmpsi2(-1, -1, 1);
+    try test__cmpsi2(0, 0, 1);
+    try test__cmpsi2(1, 1, 1);
+    try test__cmpsi2(1073741823, 1073741823, 1);
+    try test__cmpsi2(2147483646, 2147483646, 1);
+    try test__cmpsi2(2147483647, 2147483647, 1);
+    // 2. cmp minInt,   {        minInt + 1, minInt/2, -1,0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpsi2(-2147483648, -2147483647, 0);
+    try test__cmpsi2(-2147483648, -1073741824, 0);
+    try test__cmpsi2(-2147483648, -1, 0);
+    try test__cmpsi2(-2147483648, 0, 0);
+    try test__cmpsi2(-2147483648, 1, 0);
+    try test__cmpsi2(-2147483648, 1073741823, 0);
+    try test__cmpsi2(-2147483648, 2147483646, 0);
+    try test__cmpsi2(-2147483648, 2147483647, 0);
+    // 3. cmp minInt+1, {minInt,             minInt/2, -1,0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpsi2(-2147483647, -2147483648, 2);
+    try test__cmpsi2(-2147483647, -1073741824, 0);
+    try test__cmpsi2(-2147483647, -1, 0);
+    try test__cmpsi2(-2147483647, 0, 0);
+    try test__cmpsi2(-2147483647, 1, 0);
+    try test__cmpsi2(-2147483647, 1073741823, 0);
+    try test__cmpsi2(-2147483647, 2147483646, 0);
+    try test__cmpsi2(-2147483647, 2147483647, 0);
+    // 4. cmp minInt/2, {minInt, minInt + 1,           -1,0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpsi2(-1073741824, -2147483648, 2);
+    try test__cmpsi2(-1073741824, -2147483647, 2);
+    try test__cmpsi2(-1073741824, -1, 0);
+    try test__cmpsi2(-1073741824, 0, 0);
+    try test__cmpsi2(-1073741824, 1, 0);
+    try test__cmpsi2(-1073741824, 1073741823, 0);
+    try test__cmpsi2(-1073741824, 2147483646, 0);
+    try test__cmpsi2(-1073741824, 2147483647, 0);
+    // 5. cmp -1,       {minInt, minInt + 1, minInt/2,    0,1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpsi2(-1, -2147483648, 2);
+    try test__cmpsi2(-1, -2147483647, 2);
+    try test__cmpsi2(-1, -1073741824, 2);
+    try test__cmpsi2(-1, 0, 0);
+    try test__cmpsi2(-1, 1, 0);
+    try test__cmpsi2(-1, 1073741823, 0);
+    try test__cmpsi2(-1, 2147483646, 0);
+    try test__cmpsi2(-1, 2147483647, 0);
+    // 6. cmp 0,        {minInt, minInt + 1, minInt/2, -1,  1, maxInt/2, maxInt-1, maxInt}
+    try test__cmpsi2(0, -2147483648, 2);
+    try test__cmpsi2(0, -2147483647, 2);
+    try test__cmpsi2(0, -1073741824, 2);
+    try test__cmpsi2(0, -1, 2);
+    try test__cmpsi2(0, 1, 0);
+    try test__cmpsi2(0, 1073741823, 0);
+    try test__cmpsi2(0, 2147483646, 0);
+    try test__cmpsi2(0, 2147483647, 0);
+    // 7. cmp 1,        {minInt, minInt + 1, minInt/2, -1,0,  maxInt/2, maxInt-1, maxInt}
+    try test__cmpsi2(1, -2147483648, 2);
+    try test__cmpsi2(1, -2147483647, 2);
+    try test__cmpsi2(1, -1073741824, 2);
+    try test__cmpsi2(1, -1, 2);
+    try test__cmpsi2(1, 0, 2);
+    try test__cmpsi2(1, 1073741823, 0);
+    try test__cmpsi2(1, 2147483646, 0);
+    try test__cmpsi2(1, 2147483647, 0);
+    // 8. cmp maxInt/2, {minInt, minInt + 1, minInt/2, -1, 0, 1,          maxInt-1, maxInt}
+    try test__cmpsi2(1073741823, -2147483648, 2);
+    try test__cmpsi2(1073741823, -2147483647, 2);
+    try test__cmpsi2(1073741823, -1073741824, 2);
+    try test__cmpsi2(1073741823, -1, 2);
+    try test__cmpsi2(1073741823, 0, 2);
+    try test__cmpsi2(1073741823, 1, 2);
+    try test__cmpsi2(1073741823, 2147483646, 0);
+    try test__cmpsi2(1073741823, 2147483647, 0);
+    // 9. cmp maxInt-1, {minInt, minInt + 1, minInt/2, -1, 0, 1, maxInt/2,           maxInt}
+    try test__cmpsi2(2147483646, -2147483648, 2);
+    try test__cmpsi2(2147483646, -2147483647, 2);
+    try test__cmpsi2(2147483646, -1073741824, 2);
+    try test__cmpsi2(2147483646, -1, 2);
+    try test__cmpsi2(2147483646, 0, 2);
+    try test__cmpsi2(2147483646, 1, 2);
+    try test__cmpsi2(2147483646, 1073741823, 2);
+    try test__cmpsi2(2147483646, 2147483647, 0);
+    // 10.cmp maxInt,   {minInt, minInt + 1, minInt/2, -1, 0, 1, maxInt/2, maxInt-1,       }
+    try test__cmpsi2(2147483647, -2147483648, 2);
+    try test__cmpsi2(2147483647, -2147483647, 2);
+    try test__cmpsi2(2147483647, -1073741824, 2);
+    try test__cmpsi2(2147483647, -1, 2);
+    try test__cmpsi2(2147483647, 0, 2);
+    try test__cmpsi2(2147483647, 1, 2);
+    try test__cmpsi2(2147483647, 1073741823, 2);
+    try test__cmpsi2(2147483647, 2147483646, 2);
+}