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This patch adds a builtin constant that lowers to `freeze(poison)`.
This is necessary to patch the intrinsics like e.g., `mm256_castsi128_si256` to
be lowered to the following sequence:
%a1 = freeze <2 x double> poison // <- would like to represent this as
'__builtin_unspecified_value' in C/C++.
%res = shufflevector <2 x double> %a0, <2 x double> %a1, <4 x i32> <i32 0,
i32 1, i32 2, i32 3>
Currently it is being lowered to:
%res = shufflevector <2x double> %a0, undef, <4 x i32> <i32 0, i32 1, i32
-1, i32 -1>
The current lowering may incorrectly introduce undefined behavior.
A related, previous patch was here: https://reviews.llvm.org/D130339
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D136737
Files:
clang/include/clang-c/Index.h
clang/include/clang/AST/Expr.h
clang/include/clang/AST/RecursiveASTVisitor.h
clang/include/clang/Basic/StmtNodes.td
clang/include/clang/Serialization/ASTBitCodes.h
clang/lib/AST/ASTImporter.cpp
clang/lib/AST/Expr.cpp
clang/lib/AST/ExprClassification.cpp
clang/lib/AST/StmtPrinter.cpp
clang/lib/AST/StmtProfile.cpp
clang/lib/Sema/SemaExceptionSpec.cpp
clang/lib/Sema/TreeTransform.h
clang/lib/Serialization/ASTReaderStmt.cpp
clang/lib/Serialization/ASTWriterStmt.cpp
clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
clang/tools/libclang/CXCursor.cpp
Index: clang/tools/libclang/CXCursor.cpp
===================================================================
--- clang/tools/libclang/CXCursor.cpp
+++ clang/tools/libclang/CXCursor.cpp
@@ -475,6 +475,10 @@
K = CXCursor_GNUNullExpr;
break;
+ case Stmt::UnspecifiedValueExprClass:
+ K = CXCursor_UnspecifiedValueExpr;
+ break;
+
case Stmt::CXXStaticCastExprClass:
K = CXCursor_CXXStaticCastExpr;
break;
Index: clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -1889,6 +1889,7 @@
case Stmt::ObjCSelectorExprClass:
case Stmt::ParenListExprClass:
case Stmt::ShuffleVectorExprClass:
+ case Stmt::UnspecifiedValueExprClass:
case Stmt::ConvertVectorExprClass:
case Stmt::VAArgExprClass:
case Stmt::CUDAKernelCallExprClass:
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1195,6 +1195,12 @@
Code = serialization::EXPR_GNU_NULL;
}
+void ASTStmtWriter::VisitUnspecifiedValueExpr(UnspecifiedValueExpr *E) {
+ VisitExpr(E);
+ Record.AddSourceLocation(E->getTokenLocation());
+ Code = serialization::EXPR_UNSPECIFIED_VALUE;
+}
+
void ASTStmtWriter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
VisitExpr(E);
Record.push_back(E->getNumSubExprs());
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1316,6 +1316,11 @@
E->setTokenLocation(readSourceLocation());
}
+void ASTStmtReader::VisitUnspecifiedValueExpr(UnspecifiedValueExpr *E) {
+ VisitExpr(E);
+ E->setTokenLocation(readSourceLocation());
+}
+
void ASTStmtReader::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
VisitExpr(E);
SmallVector<Expr *, 16> Exprs;
@@ -3077,6 +3082,10 @@
S = new (Context) GNUNullExpr(Empty);
break;
+ case EXPR_UNSPECIFIED_VALUE:
+ S = new (Context) UnspecifiedValueExpr(Empty);
+ break;
+
case EXPR_SHUFFLE_VECTOR:
S = new (Context) ShuffleVectorExpr(Empty);
break;
Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -11719,6 +11719,12 @@
return E;
}
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformUnspecifiedValueExpr(UnspecifiedValueExpr *E) {
+ return E;
+}
+
template<typename Derived>
ExprResult
TreeTransform<Derived>::TransformCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
Index: clang/lib/Sema/SemaExceptionSpec.cpp
===================================================================
--- clang/lib/Sema/SemaExceptionSpec.cpp
+++ clang/lib/Sema/SemaExceptionSpec.cpp
@@ -1404,6 +1404,7 @@
case Expr::SourceLocExprClass:
case Expr::ConceptSpecializationExprClass:
case Expr::RequiresExprClass:
+ case Expr::UnspecifiedValueExprClass:
// These expressions can never throw.
return CT_Cannot;
Index: clang/lib/AST/StmtProfile.cpp
===================================================================
--- clang/lib/AST/StmtProfile.cpp
+++ clang/lib/AST/StmtProfile.cpp
@@ -1472,6 +1472,10 @@
VisitExpr(S);
}
+void StmtProfiler::VisitUnspecifiedValueExpr(const UnspecifiedValueExpr *S) {
+ VisitExpr(S);
+}
+
void StmtProfiler::VisitVAArgExpr(const VAArgExpr *S) {
VisitExpr(S);
}
Index: clang/lib/AST/StmtPrinter.cpp
===================================================================
--- clang/lib/AST/StmtPrinter.cpp
+++ clang/lib/AST/StmtPrinter.cpp
@@ -1674,6 +1674,10 @@
OS << "__null";
}
+void StmtPrinter::VisitUnspecifiedValueExpr(UnspecifiedValueExpr *) {
+ OS << "__builtin_unspecified_value";
+}
+
void StmtPrinter::VisitShuffleVectorExpr(ShuffleVectorExpr *Node) {
OS << "__builtin_shufflevector(";
for (unsigned i = 0, e = Node->getNumSubExprs(); i != e; ++i) {
Index: clang/lib/AST/ExprClassification.cpp
===================================================================
--- clang/lib/AST/ExprClassification.cpp
+++ clang/lib/AST/ExprClassification.cpp
@@ -167,6 +167,7 @@
case Expr::OffsetOfExprClass:
case Expr::CXXThrowExprClass:
case Expr::ShuffleVectorExprClass:
+ case Expr::UnspecifiedValueExprClass:
case Expr::ConvertVectorExprClass:
case Expr::IntegerLiteralClass:
case Expr::FixedPointLiteralClass:
Index: clang/lib/AST/Expr.cpp
===================================================================
--- clang/lib/AST/Expr.cpp
+++ clang/lib/AST/Expr.cpp
@@ -3638,6 +3638,7 @@
case SubstNonTypeTemplateParmExprClass:
case MaterializeTemporaryExprClass:
case ShuffleVectorExprClass:
+ case UnspecifiedValueExprClass:
case ConvertVectorExprClass:
case AsTypeExprClass:
// These have a side-effect if any subexpression does.
Index: clang/lib/AST/ASTImporter.cpp
===================================================================
--- clang/lib/AST/ASTImporter.cpp
+++ clang/lib/AST/ASTImporter.cpp
@@ -618,6 +618,7 @@
ExpectedStmt VisitChooseExpr(ChooseExpr *E);
ExpectedStmt VisitShuffleVectorExpr(ShuffleVectorExpr *E);
ExpectedStmt VisitGNUNullExpr(GNUNullExpr *E);
+ ExpectedStmt VisitUnspecifiedValueExpr(UnspecifiedValueExpr *E);
ExpectedStmt VisitGenericSelectionExpr(GenericSelectionExpr *E);
ExpectedStmt VisitPredefinedExpr(PredefinedExpr *E);
ExpectedStmt VisitDeclRefExpr(DeclRefExpr *E);
@@ -6987,6 +6988,20 @@
return new (Importer.getToContext()) GNUNullExpr(*TypeOrErr, *BeginLocOrErr);
}
+ExpectedStmt ASTNodeImporter::VisitUnspecifiedValueExpr(
+ UnspecifiedValueExpr *E) {
+ ExpectedType TypeOrErr = import(E->getType());
+ if (!TypeOrErr)
+ return TypeOrErr.takeError();
+
+ ExpectedSLoc BeginLocOrErr = import(E->getBeginLoc());
+ if (!BeginLocOrErr)
+ return BeginLocOrErr.takeError();
+
+ return new (Importer.getToContext()) UnspecifiedValueExpr(*TypeOrErr,
+ *BeginLocOrErr);
+}
+
ExpectedStmt
ASTNodeImporter::VisitGenericSelectionExpr(GenericSelectionExpr *E) {
Error Err = Error::success();
Index: clang/include/clang/Serialization/ASTBitCodes.h
===================================================================
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -1706,6 +1706,9 @@
/// A GNUNullExpr record.
EXPR_GNU_NULL,
+ // An UnspecifiedValueExpr record.
+ EXPR_UNSPECIFIED_VALUE,
+
/// A SourceLocExpr record.
EXPR_SOURCE_LOC,
Index: clang/include/clang/Basic/StmtNodes.td
===================================================================
--- clang/include/clang/Basic/StmtNodes.td
+++ clang/include/clang/Basic/StmtNodes.td
@@ -202,6 +202,7 @@
def TypoExpr : StmtNode<Expr>;
def RecoveryExpr : StmtNode<Expr>;
def BuiltinBitCastExpr : StmtNode<ExplicitCastExpr>;
+def UnspecifiedValueExpr : StmtNode<Expr>;
// Microsoft Extensions.
def MSPropertyRefExpr : StmtNode<Expr>;
Index: clang/include/clang/AST/RecursiveASTVisitor.h
===================================================================
--- clang/include/clang/AST/RecursiveASTVisitor.h
+++ clang/include/clang/AST/RecursiveASTVisitor.h
@@ -2797,6 +2797,7 @@
DEF_TRAVERSE_STMT(ConvertVectorExpr, {})
DEF_TRAVERSE_STMT(StmtExpr, {})
DEF_TRAVERSE_STMT(SourceLocExpr, {})
+DEF_TRAVERSE_STMT(UnspecifiedValueExpr, {})
DEF_TRAVERSE_STMT(UnresolvedLookupExpr, {
TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
Index: clang/include/clang/AST/Expr.h
===================================================================
--- clang/include/clang/AST/Expr.h
+++ clang/include/clang/AST/Expr.h
@@ -4634,6 +4634,43 @@
}
};
+/// UnspecifiedValueExpr - clang-specific value __builtin_unspecified_value.
+/// This AST node represents freeze(poison) in LLVM IR.
+class UnspecifiedValueExpr : public Expr {
+ /// TokenLoc - The location of the __builtin_specified_value keyword.
+ SourceLocation TokenLoc;
+
+public:
+ UnspecifiedValueExpr(QualType Ty, SourceLocation Loc)
+ : Expr(UnspecifiedValueExprClass, Ty, VK_PRValue, OK_Ordinary),
+ TokenLoc(Loc) {
+ setDependence(ExprDependence::None);
+ }
+
+ /// Build an empty GNU __null expression.
+ explicit UnspecifiedValueExpr(EmptyShell Empty) :
+ Expr(UnspecifiedValueExprClass, Empty) { }
+
+ /// getTokenLocation - The location of the __null token.
+ SourceLocation getTokenLocation() const { return TokenLoc; }
+ void setTokenLocation(SourceLocation L) { TokenLoc = L; }
+
+ SourceLocation getBeginLoc() const LLVM_READONLY { return TokenLoc; }
+ SourceLocation getEndLoc() const LLVM_READONLY { return TokenLoc; }
+
+ static bool classof(const Stmt *T) {
+ return T->getStmtClass() == UnspecifiedValueExprClass;
+ }
+
+ // Iterators
+ child_range children() {
+ return child_range(child_iterator(), child_iterator());
+ }
+ const_child_range children() const {
+ return const_child_range(const_child_iterator(), const_child_iterator());
+ }
+};
+
/// Represents a call to the builtin function \c __builtin_va_arg.
class VAArgExpr : public Expr {
Stmt *Val;
Index: clang/include/clang-c/Index.h
===================================================================
--- clang/include/clang-c/Index.h
+++ clang/include/clang-c/Index.h
@@ -1531,7 +1531,12 @@
*/
CXCursor_RequiresExpr = 154,
- CXCursor_LastExpr = CXCursor_RequiresExpr,
+ /**
+ * A clang-builtin of unspecified value.
+ */
+ CXCursor_UnspecifiedValueExpr = 155,
+
+ CXCursor_LastExpr = CXCursor_UnspecifiedValueExpr,
/* Statements */
CXCursor_FirstStmt = 200,
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