Compiling for several operand memories

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#1

Hello,
My target has two data memories, each with its own load/store instructions but also has some instructions using both memories. I want to be able to access both memories in C-programs through the address space attribute.
I have two ideas so far:
Either: use two sets of addressing modes in InstrInfo.td:
def ADDRrr_A : ComplexPattern<i16, 2, “SelectADDRrr_A", [], []>;
def ADDRri : ComplexPattern<i16, 2, “SelectADDRri”, [frameindex], []>;
and
def ADDRrr_B : ComplexPattern<i16, 2, “SelectADDRrr_B”, [], []>;

Or: do something in one of the lowering functions to catch load and stores, look at their address space attribute to pick the right assembly instruction

Can someone hint me on how this can be implemented? Any input would be greatly appreciated.

best
-Magnus

#2

Have not gotten much further on this, I can so far only use one memory with

(for example)
def LDr1 : F1< (outs GenRegs:$dst), (ins GenRegs:$addr),
                  "ld*0* $dst, ($addr)",
                  [(set GenRegs:$dst, (load GenRegs:$addr))],IIGenLoad>;

and

def LDrr : F1< (outs GenRegs:$dst), (ins MEMrr:$addr),
                  "ld*0* $dst, ($addr)",
                  [(set GenRegs:$dst, (load ADDRrr:$addr))],IIGenLoad>;

What i want to do is to be able to also have these two:

def LDr1 : F1< (outs GenRegs:$dst), (ins GenRegs:$addr),
                  "ld*1* $dst, ($addr)",
                  [(set GenRegs:$dst, (load GenRegs:$addr))],IIGenLoad>;

and

def LDrr : F1< (outs GenRegs:$dst), (ins MEMrr:$addr),
                  "ld*1* $dst, ($addr)",
                  [(set GenRegs:$dst, (load ADDRrr:$addr))],IIGenLoad>;

but they should only match when accessing data structres whose address space
attribute is set to 1.
Can I use the predicate field in the instruction class to achieve this? If
so, how :confused: ?

-Magnus

#3

Hi Magnus,

We've the same situation in our back-end, two memories with its corresponding loads/stores each one. In order to select between two different loads (and stores), we have defined two complex patterns requiring its parent node (SDNPWantParent) so we can get the address space number.

def MEMA : ComplexPattern<iPTR, 3, "SelectAddrA", [], [SDNPWantParent]>;
def MEMB : ComplexPattern<iPTR, 3, "SelectAddrB", [], [SDNPWantParent]>;

Then in SelectAddrA/B, you can specify the address space number for which you want your select function to work on.

bool SelectAddrA(SDNode *Parent, ...) {
...
AddrSpace = cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
if (AddrSpace !=A)
     return false;
...
}

Hope this helps!

Regards,
Ivan