commit 7abf863f761cfe487c1406e7f6e03a79b4ab3ca8
author Lewis Revill <lewis.revill@embecosm.com> Fri Aug 16 10:28:34 2019 +0000
committer Lewis Revill <lewis.revill@embecosm.com> Fri Aug 16 10:28:34 2019 +0000
tree 2c395d439524a595fbaec47552da90df1049256e
parent 59894d4668530e5de9eba1b048d6c615c9459dc6

[RISCV] Lower inline asm constraint A for RISC-V

This allows arguments with the constraint A to be lowered to input nodes
for RISC-V, which implies a memory address stored in a register.

This patch adds the minimal amount of code required to get operands with
the right constraints to compile.

https://reviews.llvm.org/D54296

llvm-svn: 369095

llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp

diff --git a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
index d0a3af3..8439278 100644
--- a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -179,6 +179,9 @@
     // operand and need no special handling.
     OutOps.push_back(Op);
     return false;
+  case InlineAsm::Constraint_A:
+    OutOps.push_back(Op);
+    return false;
   default:
     break;
   }

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index e822b52..a9c4b69 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2437,6 +2437,8 @@
     case 'J':
     case 'K':
       return C_Immediate;
+    case 'A':
+      return C_Memory;
     }
   }
   return TargetLowering::getConstraintType(Constraint);
@@ -2556,6 +2558,21 @@
   return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT);
 }
 
+unsigned
+RISCVTargetLowering::getInlineAsmMemConstraint(StringRef ConstraintCode) const {
+  // Currently only support length 1 constraints.
+  if (ConstraintCode.size() == 1) {
+    switch (ConstraintCode[0]) {
+    case 'A':
+      return InlineAsm::Constraint_A;
+    default:
+      break;
+    }
+  }
+
+  return TargetLowering::getInlineAsmMemConstraint(ConstraintCode);
+}
+
 void RISCVTargetLowering::LowerAsmOperandForConstraint(
     SDValue Op, std::string &Constraint, std::vector<SDValue> &Ops,
     SelectionDAG &DAG) const {

llvm/lib/Target/RISCV/RISCVISelLowering.h

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
index f28c475..e2059e7 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -93,6 +93,9 @@
   const char *getTargetNodeName(unsigned Opcode) const override;
 
   ConstraintType getConstraintType(StringRef Constraint) const override;
+
+  unsigned getInlineAsmMemConstraint(StringRef ConstraintCode) const override;
+
   std::pair<unsigned, const TargetRegisterClass *>
   getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
                                StringRef Constraint, MVT VT) const override;