[clang] d704ba2 - [clang][Interp] Implement div opcode

[Timm Bäder via cfe-commits]

Author: Timm Bäder
Date: 2022-10-14T12:57:57+02:00
New Revision: d704ba26b9144829f1c4905c168f6b6278c7a3e6

URL: https://github.com/llvm/llvm-project/commit/d704ba26b9144829f1c4905c168f6b6278c7a3e6
DIFF: https://github.com/llvm/llvm-project/commit/d704ba26b9144829f1c4905c168f6b6278c7a3e6.diff

LOG: [clang][Interp] Implement div opcode

Implement an opcode for division of two integrals.

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

Added: 
    

Modified: 
    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

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index 1574f8b6c6c8..107fd77c974d 100644
--- 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 c7e558965531..b50a567d18c7 100644
--- a/clang/lib/AST/Interp/Integral.h
+++ b/clang/lib/AST/Interp/Integral.h
@@ -212,6 +212,11 @@ template <unsigned Bits, bool Signed> class Integral final {
     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 4d0c7f62f46c..6ad3a6aeaa31 100644
--- 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 61f97337fd04..f47f6492fcd7 100644
--- 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 19c80f478d1a..cc868266e4a2 100644
--- 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}} \
+
+};