Add @select

@select(
    comptime T: type,
    pred: std.meta.Vector(len, bool),
    a: std.meta.Vector(len, T),
    b: std.meta.Vector(len, T)
) std.meta.Vector(len, T)

Constructs a vector from a & b, based on the values in the predicate vector. For indices where the predicate value is true, the corresponding
element from the a vector is selected, and otherwise from b.

1 files changed, 25 insertions, 0 deletions

diff --git a/test/behavior/select.zig b/test/behavior/select.zig
new file mode 100644
index 0000000000..5c69094413
--- /dev/null
+++ b/test/behavior/select.zig
@@ -0,0 +1,25 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const mem = std.mem;
+const expect = std.testing.expect;
+const Vector = std.meta.Vector;
+
+test "@select" {
+    const S = struct {
+        fn doTheTest() !void {
+            var a: Vector(4, bool) = [4]bool{ true, false, true, false };
+            var b: Vector(4, i32) = [4]i32{ -1, 4, 999, -31 };
+            var c: Vector(4, i32) = [4]i32{ -5, 1, 0, 1234 };
+            var abc = @select(i32, a, b, c);
+            try expect(mem.eql(i32, &@as([4]i32, abc), &[4]i32{ -1, 1, 999, 1234 }));
+
+            var x: Vector(4, bool) = [4]bool{ false, false, false, true };
+            var y: Vector(4, f32) = [4]f32{ 0.001, 33.4, 836, -3381.233 };
+            var z: Vector(4, f32) = [4]f32{ 0.0, 312.1, -145.9, 9993.55 };
+            var xyz = @select(f32, x, y, z);
+            try expect(mem.eql(f32, &@as([4]f32, xyz), &[4]f32{ 0.0, 312.1, -145.9, -3381.233 }));
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}