Detect when the current generation point is unreachable after emitting
expressions.
- This generally catches the important case of noreturn functions.
- With the last two changes, we are down to 152 unreachable blocks emitted on
403.gcc, vs the 1805 we started with.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76364 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 4e6ec82..04b26ea 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -68,10 +68,19 @@
default:
// Must be an expression in a stmt context. Emit the value (to get
// side-effects) and ignore the result.
- if (const Expr *E = dyn_cast<Expr>(S)) {
- EmitAnyExpr(E, 0, false, true);
- } else {
+ if (!isa<Expr>(S))
ErrorUnsupported(S, "statement");
+
+ EmitAnyExpr(cast<Expr>(S), 0, false, true);
+
+ // Expression emitters don't handle unreachable blocks yet, so look for one
+ // explicitly here. This handles the common case of a call to a noreturn
+ // function.
+ if (llvm::BasicBlock *CurBB = Builder.GetInsertBlock()) {
+ if (CurBB->empty() && CurBB->use_empty()) {
+ CurBB->eraseFromParent();
+ Builder.ClearInsertionPoint();
+ }
}
break;
case Stmt::IndirectGotoStmtClass: