[globalisel][tablegen] Generalize pointer-type inference by introducing ptypeN. NFC

ptypeN is functionally the same as typeN except that it informs the
SelectionDAG importer that an operand should be treated as a pointer even
if it was written as iN. This is important for patterns that use iN instead
of iPTR to represent pointers. E.g.:
  (set GPR64:$dst, (load GPR64:$addr))

Previously, this was handled as a hardcoded special case for the appropriate
operands to G_LOAD and G_STORE.

llvm-svn: 318574

3 files changed, 18 insertions, 4 deletions

diff --git a/llvm/utils/TableGen/CodeGenInstruction.cpp b/llvm/utils/TableGen/CodeGenInstruction.cpp
index 8fa3050e078..44ee16f6fd7 100644
--- a/llvm/utils/TableGen/CodeGenInstruction.cpp
+++ b/llvm/utils/TableGen/CodeGenInstruction.cpp
@@ -430,6 +430,17 @@ FlattenAsmStringVariants(StringRef Cur, unsigned Variant) {
   return Res;
 }
 
+bool CodeGenInstruction::isOperandAPointer(unsigned i) const {
+  if (DagInit *ConstraintList = TheDef->getValueAsDag("InOperandList")) {
+    if (i < ConstraintList->getNumArgs()) {
+      if (DefInit *Constraint = dyn_cast<DefInit>(ConstraintList->getArg(i))) {
+        return Constraint->getDef()->isSubClassOf("TypedOperand") &&
+               Constraint->getDef()->getValueAsBit("IsPointer");
+      }
+    }
+  }
+  return false;
+}
 
 //===----------------------------------------------------------------------===//
 /// CodeGenInstAlias Implementation
diff --git a/llvm/utils/TableGen/CodeGenInstruction.h b/llvm/utils/TableGen/CodeGenInstruction.h
index e173e153879..9cff95b1247 100644
--- a/llvm/utils/TableGen/CodeGenInstruction.h
+++ b/llvm/utils/TableGen/CodeGenInstruction.h
@@ -284,6 +284,12 @@ template <typename T> class ArrayRef;
     /// include text from the specified variant, returning the new string.
     static std::string FlattenAsmStringVariants(StringRef AsmString,
                                                 unsigned Variant);
+
+    // Is the specified operand in a generic instruction implicitly a pointer.
+    // This can be used on intructions that use typeN or ptypeN to identify
+    // operands that should be considered as pointers even though SelectionDAG
+    // didn't make a distinction between integer and pointers.
+    bool isOperandAPointer(unsigned i) const;
   };
 
 
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
index 56a638483c0..505864bb0d5 100644
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -2546,10 +2546,7 @@ Expected<InstructionMatcher &> GlobalISelEmitter::createAndImportSelDAGMatcher(
       // SelectionDAG allows pointers to be represented with iN since it doesn't
       // distinguish between pointers and integers but they are different types in GlobalISel.
       // Coerce integers to pointers to address space 0 if the context indicates a pointer.
-      // TODO: Find a better way to do this, SDTCisPtrTy?
-      bool OperandIsAPointer =
-          (SrcGIOrNull->TheDef->getName() == "G_LOAD" && i == 0) ||
-          (SrcGIOrNull->TheDef->getName() == "G_STORE" && i == 1);
+      bool OperandIsAPointer = SrcGIOrNull->isOperandAPointer(i);
 
       // For G_INTRINSIC/G_INTRINSIC_W_SIDE_EFFECTS, the operand immediately
       // following the defs is an intrinsic ID.