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x64: fix struct_field_val for structs fitting in register

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This commit is contained in:
Jakub Konka
2022-03-24 16:38:04 +01:00
parent 77352c5bea
commit 9d2ff7ed16
1 changed files with 5 additions and 1 deletions
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6
src/arch/x86_64/CodeGen.zig
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@@ -2884,6 +2884,8 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
break :blk dst_mcv;
}
};
dst_mcv.freezeIfRegister(&self.register_manager);
defer dst_mcv.unfreezeIfRegister(&self.register_manager);
// Shift by struct_field_offset.
const shift = @intCast(u8, struct_field_offset * @sizeOf(usize));
@@ -2893,7 +2895,9 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
const max_reg_bit_width = Register.rax.size();
const mask_shift = @intCast(u6, (max_reg_bit_width - struct_field_ty.bitSize(self.target.*)));
const mask = (~@as(u64, 0)) >> mask_shift;
try self.genBinMathOpMir(.@"and", Type.usize, dst_mcv, .{ .immediate = mask });
const tmp_reg = try self.copyToTmpRegister(Type.usize, .{ .immediate = mask });
try self.genBinMathOpMir(.@"and", Type.usize, dst_mcv, .{ .register = tmp_reg });
break :result dst_mcv;
},