authorgravatar for emily.a.bellows@hey.comEmily Bellows <emily.a.bellows@hey.com> 2021-10-29 21:04:54-04:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2021-10-30 16:09:55-04:00
log969bcb6a59eadb2ef46a9784286728a25d275c24
tree8fff245884c9df30a82024e1ff30baf3bf5444ed
parent1de6f9a267bf9247b62b385fc793586e60f78376

C backend: implement signed trunc

3 files changed, 14 insertions(+), 4 deletions(-)

src/codegen/c.zig+8-1
......@@ -1390,7 +1390,14 @@ fn airTrunc(f: *Function, inst: Air.Inst.Index) !CValue {
13901390 return local;
13911391 },
13921392 .signed => {
1393 return f.fail("TODO: C backend: implement trunc for signed integers", .{});
1393 const operand_ty = f.air.typeOf(ty_op.operand);
1394 const c_bits = toCIntBits(operand_ty.intInfo(target).bits) orelse
1395 return f.fail("TODO: C backend: implement integer types larger than 128 bits", .{});
1396 const shift_rhs = c_bits - dest_bits;
1397 try writer.print("(int{d}_t)((uint{d}_t)", .{ c_bits, c_bits });
1398 try f.writeCValue(writer, operand);
1399 try writer.print(" << {d}) >> {d};\n", .{ shift_rhs, shift_rhs });
1400 return local;
13941401 },
13951402 }
13961403}
test/behavior.zig+1-1
......@@ -5,6 +5,7 @@ test {
55 _ = @import("behavior/basic.zig");
66 _ = @import("behavior/bool.zig");
77 _ = @import("behavior/if.zig");
8 _ = @import("behavior/truncate.zig");
89
910 if (builtin.object_format != .c) {
1011 // Tests that pass for stage1 and stage2 but not the C backend.
......@@ -60,7 +61,6 @@ test {
6061 _ = @import("behavior/switch.zig");
6162 _ = @import("behavior/this.zig");
6263 _ = @import("behavior/translate_c_macros.zig");
63 _ = @import("behavior/truncate.zig");
6464 _ = @import("behavior/underscore.zig");
6565 _ = @import("behavior/union.zig");
6666 _ = @import("behavior/usingnamespace.zig");
test/behavior/basic.zig+5-2
......@@ -27,8 +27,11 @@ test "truncate to non-power-of-two integers" {
2727 try testTrunc(u32, u1, 0b10110, 0b0);
2828 try testTrunc(u32, u2, 0b10101, 0b01);
2929 try testTrunc(u32, u2, 0b10110, 0b10);
30 // TODO add test coverage for this!
31 // try testTrunc(i32, i3, -4, -4);
30 try testTrunc(i32, i5, -4, -4);
31 try testTrunc(i32, i5, 4, 4);
32 try testTrunc(i32, i5, -28, 4);
33 try testTrunc(i32, i5, 28, -4);
34 try testTrunc(i32, i5, std.math.maxInt(i32), -1);
3235}
3336
3437fn testTrunc(comptime Big: type, comptime Little: type, big: Big, little: Little) !void {