The attached patch adds a construct that enables extending the base class’ lists rather than completely overwriting them.
The patch hasn’t gone through extensive testing yet (other than running make check).
The lists can be extended either with a “+=” operator in a let statement or placing a '"+" in front of a superclass:
- Example 1:
def D0 : C1 {
let Predicates += [P2]; // Append P2 to C1’s Predicates
}
- Example 2:
def D0 : C1, +AddP1;
Using a real example, MOVi16 (in ARMInstrInfo.td) which is defined as
def MOVi16 : AI1<0b1000, (outs GPR:$Rd), (ins imm0_65535_expr:$imm),
DPFrm, IIC_iMOVi,
“movw”, “\t$Rd, $imm”,
[(set GPR:$Rd, imm0_65535:$imm)]>,
Requires<[IsARM, HasV6T2]>, UnaryDP {
can be rewritten to this:
class PredHasV6T2 {
list Predicates = [HasV6T2];
}
def MOVi16 : AI1<0b1000, (outs GPR:$Rd), (ins imm0_65535_expr:$imm),
DPFrm, IIC_iMOVi,
“movw”, “\t$Rd, $imm”,
[(set GPR:$Rd, imm0_65535:$imm)]>,
+PredHasV6T2, UnaryDP {
Since AI1 already has “IsARM” in its predicate list, MOVi16 just has to extend the list with [HasV6T2].
Also, I changed the last statement of ListRecTy::convertValue (in lib/TableGen/Record.cpp) to pass the element type of the list rather than the list type.
I would appreciate if someone could take a look at this code and tell me whether this is correct.
tblgen-list1.patch (7.86 KB)
tblgen-test0.td (738 Bytes)
).