mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-01-10 09:25:11 +00:00
Code Issues Packages Projects Releases Wiki Activity

x86_64: fix overflow of extended multiply

Browse Source
This commit is contained in:
Jacob Young 2023-04-14 04:47:33 -04:00
parent 08055f2942
commit c03771e173
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/arch/x86_64/CodeGen.zig
View File

@ -2089,12 +2089,14 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
else => {},
}
// For now, this is the only supported multiply that doesn't fit in a register.
assert(dst_info.bits == 128 and src_pl.data == 64);
const dst_abi_size = @intCast(i32, dst_ty.abiSize(self.target.*));
const dst_mcv = try self.allocRegOrMem(inst, false);
try self.genSetStack(
Type.u1,
dst_mcv.stack_offset - dst_abi_size,
.{ .eflags = cc },
.{ .immediate = 0 }, // 64x64 -> 128 never overflows
.{},
);
try self.genSetStack(dst_ty, dst_mcv.stack_offset, partial_mcv, .{});