Merging r181368:

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r181368 | rsmith | 2013-05-07 14:53:22 -0700 (Tue, 07 May 2013) | 3 lines

Don't crash in IRGen if a conditional with 'throw' in one of its branches is
used as a branch condition.

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_33@181401 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 19 insertions, 5 deletions

diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index 36642bcc48..a088d78641 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -419,14 +419,16 @@ llvm::Value *CodeGenFunction::getSelectorFromSlot() {
   return Builder.CreateLoad(getEHSelectorSlot(), "sel");
 }
 
-void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
+void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E,
+                                       bool KeepInsertionPoint) {
   if (!E->getSubExpr()) {
     EmitNoreturnRuntimeCallOrInvoke(getReThrowFn(CGM),
                                     ArrayRef<llvm::Value*>());
 
     // throw is an expression, and the expression emitters expect us
     // to leave ourselves at a valid insertion point.
-    EmitBlock(createBasicBlock("throw.cont"));
+    if (KeepInsertionPoint)
+      EmitBlock(createBasicBlock("throw.cont"));
 
     return;
   }
@@ -440,7 +442,8 @@ void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
     CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
     // This will clear insertion point which was not cleared in
     // call to EmitThrowStmt.
-    EmitBlock(createBasicBlock("throw.cont"));
+    if (KeepInsertionPoint)
+      EmitBlock(createBasicBlock("throw.cont"));
     return;
   }
   
@@ -478,7 +481,8 @@ void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
 
   // throw is an expression, and the expression emitters expect us
   // to leave ourselves at a valid insertion point.
-  EmitBlock(createBasicBlock("throw.cont"));
+  if (KeepInsertionPoint)
+    EmitBlock(createBasicBlock("throw.cont"));
 }
 
 void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 791c1a8152..75c60edbba 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -928,6 +928,16 @@ void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
     return;
   }
 
+  if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) {
+    // Conditional operator handling can give us a throw expression as a
+    // condition for a case like:
+    //   br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f)
+    // Fold this to:
+    //   br(c, throw x, br(y, t, f))
+    EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false);
+    return;
+  }
+
   // Emit the code with the fully general case.
   llvm::Value *CondV = EvaluateExprAsBool(Cond);
   Builder.CreateCondBr(CondV, TrueBlock, FalseBlock);
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 08e60c43ce..ff74c15c38 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -2708,7 +2708,7 @@ public:
   }
   void enterNonTrivialFullExpression(const ExprWithCleanups *E);
 
-  void EmitCXXThrowExpr(const CXXThrowExpr *E);
+  void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint = true);
 
   void EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Dest);