[llvm] 54c1954 - [GlobalISel] Revise 'assignCustomValue' interface (#77824)

[via llvm-commits]

Author: darkbuck
Date: 2024-01-12T10:41:55+07:00
New Revision: 54c19546ba6ffd24a3bcb0c0d145309ed6f8ce46

URL: https://github.com/llvm/llvm-project/commit/54c19546ba6ffd24a3bcb0c0d145309ed6f8ce46
DIFF: https://github.com/llvm/llvm-project/commit/54c19546ba6ffd24a3bcb0c0d145309ed6f8ce46.diff

LOG: [GlobalISel] Revise 'assignCustomValue' interface (#77824)

- Previously, 'assignCustomValue' requests the number of assigned VAs
minus 1 is returned and treats 0 as the assignment failure. However,
under that arrangment, we cannot tell a successful *single* VA custom
assignment from the failure case.
- This change requests that 'assignCustomValue' just return the number
of all VAs assigned, including the first WA so that it won't be ambigous
to tell the failure case from the single VA custom assignment.

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h
    llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
    llvm/lib/Target/ARM/ARMCallLowering.cpp
    llvm/lib/Target/Mips/MipsCallLowering.cpp
    llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h b/llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h
index ec0b3363f51694..d123ab7d8e46ed 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h
@@ -291,8 +291,8 @@ class CallLowering {
     /// \p If the handler wants the assignments to be delayed until after
     /// mem loc assignments, then it sets \p Thunk to the thunk to do the
     /// assignment.
-    /// \return The number of \p VAs that have been assigned after the first
-    ///         one, and which should therefore be skipped from further
+    /// \return The number of \p VAs that have been assigned including the
+    ///         first one, and which should therefore be skipped from further
     ///         processing.
     virtual unsigned assignCustomValue(ArgInfo &Arg, ArrayRef<CCValAssign> VAs,
                                        std::function<void()> *Thunk = nullptr) {

diff  --git a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
index 6858e030c2c75e..2953433deff1f0 100644
--- a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
@@ -694,7 +694,7 @@ bool CallLowering::handleAssignments(ValueHandler &Handler,
         DelayedOutgoingRegAssignments.emplace_back(Thunk);
       if (!NumArgRegs)
         return false;
-      j += NumArgRegs;
+      j += (NumArgRegs - 1);
       continue;
     }
 

diff  --git a/llvm/lib/Target/ARM/ARMCallLowering.cpp b/llvm/lib/Target/ARM/ARMCallLowering.cpp
index f9d9930cec6d06..38faf5c295aeeb 100644
--- a/llvm/lib/Target/ARM/ARMCallLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMCallLowering.cpp
@@ -166,11 +166,11 @@ struct ARMOutgoingValueHandler : public CallLowering::OutgoingValueHandler {
         assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
         assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
       };
-      return 1;
+      return 2;
     }
     assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
     assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
-    return 1;
+    return 2;
   }
 
   MachineInstrBuilder MIB;
@@ -341,7 +341,7 @@ struct ARMIncomingValueHandler : public CallLowering::IncomingValueHandler {
 
     MIRBuilder.buildMergeLikeInstr(Arg.Regs[0], NewRegs);
 
-    return 1;
+    return 2;
   }
 
   /// Marking a physical register as used is 
diff erent between formal

diff  --git a/llvm/lib/Target/Mips/MipsCallLowering.cpp b/llvm/lib/Target/Mips/MipsCallLowering.cpp
index 1cd360fe30f8eb..b8562902112775 100644
--- a/llvm/lib/Target/Mips/MipsCallLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsCallLowering.cpp
@@ -185,7 +185,7 @@ MipsIncomingValueHandler::assignCustomValue(CallLowering::ArgInfo &Arg,
 
   markPhysRegUsed(VALo.getLocReg());
   markPhysRegUsed(VAHi.getLocReg());
-  return 1;
+  return 2;
 }
 
 namespace {

diff  --git a/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp b/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp
index 697ad476ff8c91..5a81c5c7c9f27f 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp
@@ -146,11 +146,11 @@ struct RISCVOutgoingValueHandler : public CallLowering::OutgoingValueHandler {
 
     if (Thunk) {
       *Thunk = assignFunc;
-      return 1;
+      return 2;
     }
 
     assignFunc();
-    return 1;
+    return 2;
   }
 
 private:
@@ -266,7 +266,7 @@ struct RISCVIncomingValueHandler : public CallLowering::IncomingValueHandler {
 
     MIRBuilder.buildMergeLikeInstr(Arg.Regs[0], NewRegs);
 
-    return 1;
+    return 2;
   }
 
   /// How the physical register gets marked varies between formal