3 files changed, 27 insertions, 18 deletions

diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 7afe44658ed..6c95b600038 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -2089,16 +2089,16 @@ AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P,
 
     // Register the expressions with the CFGBuilder.
     for (const auto &D : fscope->PossiblyUnreachableDiags) {
-      if (D.stmt)
-        AC.registerForcedBlockExpression(D.stmt);
+      for (const Stmt *S : D.Stmts)
+        AC.registerForcedBlockExpression(S);
     }
 
     if (AC.getCFG()) {
       analyzed = true;
       for (const auto &D : fscope->PossiblyUnreachableDiags) {
-        bool processed = false;
-        if (D.stmt) {
-          const CFGBlock *block = AC.getBlockForRegisteredExpression(D.stmt);
+        bool AllReachable = true;
+        for (const Stmt *S : D.Stmts) {
+          const CFGBlock *block = AC.getBlockForRegisteredExpression(S);
           CFGReverseBlockReachabilityAnalysis *cra =
               AC.getCFGReachablityAnalysis();
           // FIXME: We should be able to assert that block is non-null, but
@@ -2106,15 +2106,17 @@ AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P,
           // edge cases; see test/Sema/vla-2.c.
           if (block && cra) {
             // Can this block be reached from the entrance?
-            if (cra->isReachable(&AC.getCFG()->getEntry(), block))
-              S.Diag(D.Loc, D.PD);
-            processed = true;
+            if (!cra->isReachable(&AC.getCFG()->getEntry(), block)) {
+              AllReachable = false;
+              break;
+            }
           }
+          // If we cannot map to a basic block, assume the statement is
+          // reachable.
         }
-        if (!processed) {
-          // Emit the warning anyway if we cannot map to a basic block.
+
+        if (AllReachable)
           S.Diag(D.Loc, D.PD);
-        }
       }
     }
 
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 4c2d1dc768d..d0479b832f5 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -12155,10 +12155,11 @@ class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> {
     if (OtherKind == UK_Use)
       std::swap(Mod, ModOrUse);
 
-    SemaRef.Diag(Mod->getExprLoc(),
-                 IsModMod ? diag::warn_unsequenced_mod_mod
-                          : diag::warn_unsequenced_mod_use)
-      << O << SourceRange(ModOrUse->getExprLoc());
+    SemaRef.DiagRuntimeBehavior(
+        Mod->getExprLoc(), {Mod, ModOrUse},
+        SemaRef.PDiag(IsModMod ? diag::warn_unsequenced_mod_mod
+                               : diag::warn_unsequenced_mod_use)
+            << O << SourceRange(ModOrUse->getExprLoc()));
     UI.Diagnosed = true;
   }
 
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 2d9dbdd3423..a06e7dc51e8 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16079,7 +16079,7 @@ void Sema::MarkDeclarationsReferencedInExpr(Expr *E,
 /// behavior of a program, such as passing a non-POD value through an ellipsis.
 /// Failure to do so will likely result in spurious diagnostics or failures
 /// during overload resolution or within sizeof/alignof/typeof/typeid.
-bool Sema::DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
+bool Sema::DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt*> Stmts,
                                const PartialDiagnostic &PD) {
   switch (ExprEvalContexts.back().Context) {
   case ExpressionEvaluationContext::Unevaluated:
@@ -16095,9 +16095,9 @@ bool Sema::DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
 
   case ExpressionEvaluationContext::PotentiallyEvaluated:
   case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed:
-    if (Statement && getCurFunctionOrMethodDecl()) {
+    if (!Stmts.empty() && getCurFunctionOrMethodDecl()) {
       FunctionScopes.back()->PossiblyUnreachableDiags.
-        push_back(sema::PossiblyUnreachableDiag(PD, Loc, Statement));
+        push_back(sema::PossiblyUnreachableDiag(PD, Loc, Stmts));
       return true;
     }
 
@@ -16122,6 +16122,12 @@ bool Sema::DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
   return false;
 }
 
+bool Sema::DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
+                               const PartialDiagnostic &PD) {
+  return DiagRuntimeBehavior(
+      Loc, Statement ? llvm::makeArrayRef(Statement) : llvm::None, PD);
+}
+
 bool Sema::CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
                                CallExpr *CE, FunctionDecl *FD) {
   if (ReturnType->isVoidType() || !ReturnType->isIncompleteType())