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x86_64: use math.zig to check isPowerOfTwo and calc log2_int

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This commit is contained in:
Jakub Konka
2022-05-03 11:48:30 +02:00
parent 098bee0e56
commit d48789467d
1 changed files with 8 additions and 10 deletions
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18
src/arch/x86_64/CodeGen.zig
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@@ -1085,8 +1085,7 @@ fn airTrunc(self: *Self, inst: Air.Inst.Index) !void {
// when truncating a `u16` to `u5`, for example, those top 3 bits in the result
// have to be removed. this only happens if the dst if not a power-of-two size.
const dst_bit_size = dst_ty.bitSize(self.target.*);
const is_power_of_two = (dst_bit_size & (dst_bit_size - 1)) == 0;
if (!is_power_of_two or dst_bit_size < 8) {
if (!math.isPowerOfTwo(dst_bit_size) or dst_bit_size < 8) {
const max_reg_bit_width = Register.rax.size();
const shift = @intCast(u6, max_reg_bit_width - dst_ty.bitSize(self.target.*));
const mask = (~@as(u64, 0)) >> shift;
@@ -5125,8 +5124,7 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: i32, mcv: MCValue, opts: Inl
}
const base_reg = opts.dest_stack_base orelse .rbp;
const is_power_of_two = (abi_size % 2) == 0;
if (!is_power_of_two) {
if (!math.isPowerOfTwo(abi_size)) {
self.register_manager.freezeRegs(&.{reg});
defer self.register_manager.unfreezeRegs(&.{reg});
@@ -5135,31 +5133,31 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: i32, mcv: MCValue, opts: Inl
var next_offset = stack_offset;
var remainder = abi_size;
while (remainder > 0) {
const closest_power_of_two = @as(u6, 1) << @intCast(u3, math.log2(remainder));
const nearest_power_of_two = @as(u6, 1) << math.log2_int(u3, @intCast(u3, remainder));
_ = try self.addInst(.{
.tag = .mov,
.ops = (Mir.Ops{
.reg1 = base_reg,
.reg2 = registerAlias(tmp_reg, closest_power_of_two),
.reg2 = registerAlias(tmp_reg, nearest_power_of_two),
.flags = 0b10,
}).encode(),
.data = .{ .imm = @bitCast(u32, -next_offset) },
});
if (closest_power_of_two > 1) {
if (nearest_power_of_two > 1) {
_ = try self.addInst(.{
.tag = .shr,
.ops = (Mir.Ops{
.reg1 = tmp_reg,
.flags = 0b10,
}).encode(),
.data = .{ .imm = closest_power_of_two * 8 },
.data = .{ .imm = nearest_power_of_two * 8 },
});
}
remainder -= closest_power_of_two;
next_offset -= closest_power_of_two;
remainder -= nearest_power_of_two;
next_offset -= nearest_power_of_two;
}
} else {
_ = try self.addInst(.{