riscv: implement sub-byte addition

This commit is contained in:
David Rubin 2024-07-15 04:01:44 -07:00
parent 81ca3a1d59
commit 1820f44104
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GPG Key ID: A4390FEB5F00C0A5
4 changed files with 73 additions and 14 deletions

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@ -2757,12 +2757,14 @@ fn airAddWithOverflow(func: *Func, inst: Air.Inst.Index) !void {
const ty_pl = func.air.instructions.items(.data)[@intFromEnum(inst)].ty_pl;
const extra = func.air.extraData(Air.Bin, ty_pl.payload).data;
const rhs_ty = func.typeOf(extra.rhs);
const lhs_ty = func.typeOf(extra.lhs);
const result: MCValue = if (func.liveness.isUnused(inst)) .unreach else result: {
const ty = func.typeOf(extra.lhs);
switch (ty.zigTypeTag(zcu)) {
switch (lhs_ty.zigTypeTag(zcu)) {
.Vector => return func.fail("TODO implement add with overflow for Vector type", .{}),
.Int => {
const int_info = ty.intInfo(zcu);
const int_info = lhs_ty.intInfo(zcu);
const tuple_ty = func.typeOfIndex(inst);
const result_mcv = try func.allocRegOrMem(tuple_ty, inst, false);
@ -2774,11 +2776,11 @@ fn airAddWithOverflow(func: *Func, inst: Air.Inst.Index) !void {
try func.genSetMem(
.{ .frame = offset.index },
offset.off + @as(i32, @intCast(tuple_ty.structFieldOffset(0, pt))),
ty,
lhs_ty,
add_result,
);
const trunc_reg = try func.copyToTmpRegister(ty, add_result);
const trunc_reg = try func.copyToTmpRegister(lhs_ty, add_result);
const trunc_reg_lock = func.register_manager.lockRegAssumeUnused(trunc_reg);
defer func.register_manager.unlockReg(trunc_reg_lock);
@ -2787,13 +2789,13 @@ fn airAddWithOverflow(func: *Func, inst: Air.Inst.Index) !void {
// if the result isn't equal after truncating it to the given type,
// an overflow must have happened.
try func.truncateRegister(func.typeOf(extra.lhs), trunc_reg);
try func.truncateRegister(lhs_ty, trunc_reg);
try func.genBinOp(
.cmp_neq,
add_result,
ty,
lhs_ty,
.{ .register = trunc_reg },
ty,
rhs_ty,
overflow_reg,
);
@ -2806,7 +2808,69 @@ fn airAddWithOverflow(func: *Func, inst: Air.Inst.Index) !void {
break :result result_mcv;
} else {
return func.fail("TODO: less than 8 bit or non-pow 2 addition", .{});
const rhs_mcv = try func.resolveInst(extra.rhs);
const lhs_mcv = try func.resolveInst(extra.lhs);
const rhs_reg, const rhs_lock = try func.promoteReg(rhs_ty, rhs_mcv);
const lhs_reg, const lhs_lock = try func.promoteReg(lhs_ty, lhs_mcv);
defer {
if (rhs_lock) |lock| func.register_manager.unlockReg(lock);
if (lhs_lock) |lock| func.register_manager.unlockReg(lock);
}
try func.truncateRegister(rhs_ty, rhs_reg);
try func.truncateRegister(lhs_ty, lhs_reg);
const dest_reg, const dest_lock = try func.allocReg(.int);
defer func.register_manager.unlockReg(dest_lock);
_ = try func.addInst(.{
.tag = .add,
.ops = .rrr,
.data = .{ .r_type = .{
.rs1 = rhs_reg,
.rs2 = lhs_reg,
.rd = dest_reg,
} },
});
try func.truncateRegister(func.typeOfIndex(inst), dest_reg);
const add_result: MCValue = .{ .register = dest_reg };
try func.genSetMem(
.{ .frame = offset.index },
offset.off + @as(i32, @intCast(tuple_ty.structFieldOffset(0, pt))),
lhs_ty,
add_result,
);
const trunc_reg = try func.copyToTmpRegister(lhs_ty, add_result);
const trunc_reg_lock = func.register_manager.lockRegAssumeUnused(trunc_reg);
defer func.register_manager.unlockReg(trunc_reg_lock);
const overflow_reg, const overflow_lock = try func.allocReg(.int);
defer func.register_manager.unlockReg(overflow_lock);
// if the result isn't equal after truncating it to the given type,
// an overflow must have happened.
try func.truncateRegister(lhs_ty, trunc_reg);
try func.genBinOp(
.cmp_neq,
add_result,
lhs_ty,
.{ .register = trunc_reg },
rhs_ty,
overflow_reg,
);
try func.genSetMem(
.{ .frame = offset.index },
offset.off + @as(i32, @intCast(tuple_ty.structFieldOffset(1, pt))),
Type.u1,
.{ .register = overflow_reg },
);
break :result result_mcv;
}
},
else => unreachable,

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@ -773,8 +773,6 @@ test "array init with no result pointer sets field result types" {
}
test "runtime side-effects in comptime-known array init" {
if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
var side_effects: u4 = 0;
const init = [4]u4{
blk: {

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@ -1274,7 +1274,6 @@ test "2-byte packed struct argument in C calling convention" {
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
const S = packed struct(u16) {
x: u15 = 0,

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@ -1768,8 +1768,6 @@ test "struct init with no result pointer sets field result types" {
}
test "runtime side-effects in comptime-known struct init" {
if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
var side_effects: u4 = 0;
const S = struct { a: u4, b: u4, c: u4, d: u4 };
const init = S{