[clang][Interp] Implement div opcode

Implement an opcode for division of two integrals.

Differential Revision: https://reviews.llvm.org/D134749

diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index 1574f8b..107fd77 100644 (file)
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -214,6 +214,8 @@ bool ByteCodeExprGen<Emitter>::VisitBinaryOperator(const BinaryOperator *BO) {
       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;

diff --git a/clang/lib/AST/Interp/Integral.h b/clang/lib/AST/Interp/Integral.h
index c7e5589..b50a567 100644 (file)
--- a/clang/lib/AST/Interp/Integral.h
+++ b/clang/lib/AST/Interp/Integral.h
@@ -212,6 +212,11 @@ public:
     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;

diff --git a/clang/lib/AST/Interp/Interp.h b/clang/lib/AST/Interp/Interp.h
index 4d0c7f6..6ad3a6a 100644 (file)
--- a/clang/lib/AST/Interp/Interp.h
+++ b/clang/lib/AST/Interp/Interp.h
@@ -186,6 +186,39 @@ bool Rem(InterpState &S, CodePtr OpPC) {
   return false;
 }
 
+/// 1) Pops the RHS from the stack.
+/// 2) Pops the LHS from the stack.
+/// 3) Pushes 'LHS / RHS' on the stack
+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;
+  }
+
+  if (LHS.isSigned() && LHS.isMin() && RHS.isNegative() && RHS.isMinusOne()) {
+    APSInt LHSInt = LHS.toAPSInt();
+    SmallString<32> Trunc;
+    (-LHSInt.extend(LHSInt.getBitWidth() + 1)).toString(Trunc, 10);
+    const SourceInfo &Loc = S.Current->getSource(OpPC);
+    const Expr *E = S.Current->getExpr(OpPC);
+    S.CCEDiag(Loc, diag::note_constexpr_overflow) << Trunc << E->getType();
+    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
 //===----------------------------------------------------------------------===//

diff --git a/clang/lib/AST/Interp/Opcodes.td b/clang/lib/AST/Interp/Opcodes.td
index 61f9733..f47f649 100644 (file)
--- a/clang/lib/AST/Interp/Opcodes.td
+++ b/clang/lib/AST/Interp/Opcodes.td
@@ -401,7 +401,10 @@ def Rem : Opcode {
   let Types = [NumberTypeClass];
   let HasGroup = 1;
 }
-
+def Div : Opcode {
+  let Types = [NumberTypeClass];
+  let HasGroup = 1;
+}
 
 //===----------------------------------------------------------------------===//
 // Unary operators.

diff --git a/clang/test/AST/Interp/literals.cpp b/clang/test/AST/Interp/literals.cpp
index 19c80f4..cc86826 100644 (file)
--- a/clang/test/AST/Interp/literals.cpp
+++ b/clang/test/AST/Interp/literals.cpp
@@ -188,3 +188,25 @@ namespace rem {
                                    // expected-note {{value 2147483648 is outside the range}} \
 
 };
+
+namespace div {
+  constexpr int zero() { return 0; }
+  static_assert(12 / 3 == 4, "");
+  static_assert(12 / zero() == 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, "");
+
+  constexpr int x = INT_MIN / - 1; // ref-error {{must be initialized by a constant expression}} \
+                                   // ref-note {{value 2147483648 is outside the range}} \
+                                   // expected-error {{must be initialized by a constant expression}} \
+                                   // expected-note {{value 2147483648 is outside the range}} \
+
+};