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-rw-r--r--clang/lib/CodeGen/CGExpr.cpp26
1 files changed, 17 insertions, 9 deletions
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index b5d6c659e9e..719147a58e0 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -568,15 +568,23 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
// The glvalue must not be an empty glvalue.
llvm::Value *IsNonNull = Builder.CreateIsNotNull(Ptr);
- if (AllowNullPointers) {
- // When performing pointer casts, it's OK if the value is null.
- // Skip the remaining checks in that case.
- Done = createBasicBlock("null");
- llvm::BasicBlock *Rest = createBasicBlock("not.null");
- Builder.CreateCondBr(IsNonNull, Rest, Done);
- EmitBlock(Rest);
- } else {
- Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
+ // The IR builder can constant-fold the null check if the pointer points to
+ // a constant.
+ bool PtrIsNonNull =
+ IsNonNull == llvm::ConstantInt::getTrue(getLLVMContext());
+
+ // Skip the null check if the pointer is known to be non-null.
+ if (!PtrIsNonNull) {
+ if (AllowNullPointers) {
+ // When performing pointer casts, it's OK if the value is null.
+ // Skip the remaining checks in that case.
+ Done = createBasicBlock("null");
+ llvm::BasicBlock *Rest = createBasicBlock("not.null");
+ Builder.CreateCondBr(IsNonNull, Rest, Done);
+ EmitBlock(Rest);
+ } else {
+ Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
+ }
}
}
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