This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG4b5fe9c42d94: [clang][Interp] Check floating results for
NaNs (authored by tbaeder).
Changed prior to commit:
https://reviews.llvm.org/D156506?vs=545023&id=556407#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D156506/new/
https://reviews.llvm.org/D156506
Files:
clang/lib/AST/Interp/Interp.cpp
clang/lib/AST/Interp/Interp.h
clang/test/AST/Interp/floats.cpp
Index: clang/test/AST/Interp/floats.cpp
===================================================================
--- clang/test/AST/Interp/floats.cpp
+++ clang/test/AST/Interp/floats.cpp
@@ -202,3 +202,18 @@
static_assert(!(inf < nan), "");
static_assert(!(inf > nan), "");
}
+
+namespace nan {
+ constexpr double nan = __builtin_nan("");
+ static_assert(nan);
+
+ constexpr double D1 = 1 + nan; // ref-error {{must be initialized by a constant expression}} \
+ // ref-note {{produces a NaN}} \
+ // expected-error {{must be initialized by a constant expression}} \
+ // expected-note {{produces a NaN}}
+
+ constexpr double D2 = __builtin_inf() / __builtin_inf(); // ref-error {{must be initialized by a constant expression}} \
+ // ref-note {{produces a NaN}} \
+ // expected-error {{must be initialized by a constant expression}} \
+ // expected-note {{produces a NaN}}
+}
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -172,7 +172,8 @@
/// Checks if the result of a floating-point operation is valid
/// in the current context.
-bool CheckFloatResult(InterpState &S, CodePtr OpPC, APFloat::opStatus Status);
+bool CheckFloatResult(InterpState &S, CodePtr OpPC, const Floating &Result,
+ APFloat::opStatus Status);
/// Interpreter entry point.
bool Interpret(InterpState &S, APValue &Result);
@@ -304,7 +305,7 @@
Floating Result;
auto Status = Floating::add(LHS, RHS, RM, &Result);
S.Stk.push<Floating>(Result);
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, Result, Status);
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
@@ -322,7 +323,7 @@
Floating Result;
auto Status = Floating::sub(LHS, RHS, RM, &Result);
S.Stk.push<Floating>(Result);
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, Result, Status);
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
@@ -340,7 +341,7 @@
Floating Result;
auto Status = Floating::mul(LHS, RHS, RM, &Result);
S.Stk.push<Floating>(Result);
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, Result, Status);
}
/// 1) Pops the RHS from the stack.
/// 2) Pops the LHS from the stack.
@@ -443,7 +444,7 @@
Floating Result;
auto Status = Floating::div(LHS, RHS, RM, &Result);
S.Stk.push<Floating>(Result);
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, Result, Status);
}
//===----------------------------------------------------------------------===//
@@ -622,7 +623,7 @@
Ptr.deref<Floating>() = Result;
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, Result, Status);
}
inline bool Incf(InterpState &S, CodePtr OpPC, llvm::RoundingMode RM) {
@@ -1525,7 +1526,7 @@
auto Status = Floating::fromIntegral(FromAP, *Sem, RM, Result);
S.Stk.push<Floating>(Result);
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, Result, Status);
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
@@ -1550,7 +1551,7 @@
}
S.Stk.push<T>(T(Result));
- return CheckFloatResult(S, OpPC, Status);
+ return CheckFloatResult(S, OpPC, F, Status);
}
}
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -495,13 +495,25 @@
return false;
}
-bool CheckFloatResult(InterpState &S, CodePtr OpPC, APFloat::opStatus Status) {
+bool CheckFloatResult(InterpState &S, CodePtr OpPC, const Floating &Result,
+ APFloat::opStatus Status) {
+ const SourceInfo &E = S.Current->getSource(OpPC);
+
+ // [expr.pre]p4:
+ // If during the evaluation of an expression, the result is not
+ // mathematically defined [...], the behavior is undefined.
+ // FIXME: C++ rules require us to not conform to IEEE 754 here.
+ if (Result.isNan()) {
+ S.CCEDiag(E, diag::note_constexpr_float_arithmetic)
+ << /*NaN=*/true << S.Current->getRange(OpPC);
+ return S.noteUndefinedBehavior();
+ }
+
// In a constant context, assume that any dynamic rounding mode or FP
// exception state matches the default floating-point environment.
if (S.inConstantContext())
return true;
- const SourceInfo &E = S.Current->getSource(OpPC);
FPOptions FPO = E.asExpr()->getFPFeaturesInEffect(S.Ctx.getLangOpts());
if ((Status & APFloat::opInexact) &&
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