[PATCH] D134749: [clang][Interp] Implement Div opcode

[Timm Bäder via Phabricator via cfe-commits]

tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
Herald added a project: All.
tbaeder requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Same as the `rem` patch basically.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D134749

Files:
  clang/lib/AST/Interp/ByteCodeExprGen.cpp
  clang/lib/AST/Interp/Integral.h
  clang/lib/AST/Interp/Interp.h
  clang/lib/AST/Interp/Opcodes.td
  clang/test/AST/Interp/literals.cpp


Index: clang/test/AST/Interp/literals.cpp
===================================================================
--- clang/test/AST/Interp/literals.cpp
+++ clang/test/AST/Interp/literals.cpp
@@ -167,3 +167,19 @@
                                          // expected-error {{not an integral constant expression}} \
                                          // expected-note {{division by zero}}
 };
+
+namespace div {
+  constexpr int zero() { return 0; }
+  static_assert(12 / 3 == 4, "");
+  static_assert(12 / 0 == 12, ""); // ref-error {{not an integral constant expression}} \
+                                   // ref-note {{division by zero}} \
+                                   // expected-error {{not an integral constant expression}} \
+                                   // expected-note {{division by zero}}
+  static_assert(12 / -3 == -4, "");
+  static_assert(-12 / 3 == -4, "");
+
+
+  constexpr int LHS = 12;
+  constexpr long unsigned RHS = 3;
+  static_assert(LHS / RHS == 4, "");
+};
Index: clang/lib/AST/Interp/Opcodes.td
===================================================================
--- clang/lib/AST/Interp/Opcodes.td
+++ clang/lib/AST/Interp/Opcodes.td
@@ -401,7 +401,10 @@
   let Types = [NumberTypeClass];
   let HasGroup = 1;
 }
-
+def Div : Opcode {
+  let Types = [NumberTypeClass];
+  let HasGroup = 1;
+}
 
 //===----------------------------------------------------------------------===//
 // Unary operators.
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -175,6 +175,25 @@
   return false;
 }
 
+template <PrimType Name, class T = typename PrimConv<Name>::T>
+bool Div(InterpState &S, CodePtr OpPC) {
+  const T &RHS = S.Stk.pop<T>();
+  const T &LHS = S.Stk.pop<T>();
+
+  if (RHS.isZero()) {
+    const SourceInfo &Loc = S.Current->getSource(OpPC);
+    S.FFDiag(Loc, diag::note_expr_divide_by_zero);
+    return false;
+  }
+  const unsigned Bits = RHS.bitWidth() * 2;
+  T Result;
+  if (!T::div(LHS, RHS, Bits, &Result)) {
+    S.Stk.push<T>(Result);
+    return true;
+  }
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // Inv
 //===----------------------------------------------------------------------===//
Index: clang/lib/AST/Interp/Integral.h
===================================================================
--- clang/lib/AST/Interp/Integral.h
+++ clang/lib/AST/Interp/Integral.h
@@ -215,6 +215,11 @@
     return false;
   }
 
+  static bool div(Integral A, Integral B, unsigned OpBits, Integral *R) {
+    *R = Integral(A.V / B.V);
+    return false;
+  }
+
   static bool neg(Integral A, Integral *R) {
     *R = -A;
     return false;
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -213,6 +213,8 @@
       return Discard(this->emitMul(*T, BO));
     case BO_Rem:
       return Discard(this->emitRem(*T, BO));
+    case BO_Div:
+      return Discard(this->emitDiv(*T, BO));
     case BO_Assign:
       if (!this->emitStore(*T, BO))
         return false;


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