From: Manuel Klimek <klimek@google.com>
Date: Thu, 7 Aug 2014 14:25:43 +0000 (+0000)
Subject: Only have one path in the CFG for ternaries if the condition is known.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dc2fdc2c413dd4cfda859ae62ee8e2baa0542ea8;p=clang

Only have one path in the CFG for ternaries if the condition is known.

The return type analysis requires that the CFG is simplified when the
truth values of branches are statically known at analysis time.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215114 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index 20438b4787..b9698d550b 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -3711,15 +3711,24 @@ CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
   VisitForTemporaryDtors(E->getCond(), false, Context);
   CFGBlock *ConditionBlock = Block;
   CFGBlock *ConditionSucc = Succ;
+  TryResult ConditionVal = tryEvaluateBool(E->getCond());
 
   TempDtorContext TrueContext(/*IsConditional=*/true);
-  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
+  if (!ConditionVal.isFalse()) {
+    VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
+    if (ConditionVal.isTrue())
+      return Block;
+  }
   CFGBlock *TrueBlock = Block;
 
   Block = ConditionBlock;
   Succ = ConditionSucc;
   TempDtorContext FalseContext(/*IsConditional=*/true);
-  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
+  if (!ConditionVal.isTrue()) {
+    VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
+    if (ConditionVal.isFalse())
+      return Block;
+  }
 
   if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
     InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
diff --git a/test/SemaCXX/return-noreturn.cpp b/test/SemaCXX/return-noreturn.cpp
index bafeafcf1c..8490be9be3 100644
--- a/test/SemaCXX/return-noreturn.cpp
+++ b/test/SemaCXX/return-noreturn.cpp
@@ -159,6 +159,22 @@ int testTernaryUnconditionalNoreturn() {
   true ? NoReturn() : NoReturn();
 }
 
+int testTernaryStaticallyConditionalNoretrunOnTrue() {
+  true ? NoReturn() : Return();
+}
+
+int testTernaryStaticallyConditionalRetrunOnTrue() {
+  true ? Return() : NoReturn();
+} // expected-warning {{control reaches end of non-void function}}
+
+int testTernaryStaticallyConditionalNoretrunOnFalse() {
+  false ? Return() : NoReturn();
+}
+
+int testTernaryStaticallyConditionalRetrunOnFalse() {
+  false ? NoReturn() : Return();
+} // expected-warning {{control reaches end of non-void function}}
+
 int testTernaryConditionalNoreturnTrueBranch(bool value) {
   value ? (NoReturn() || NoReturn()) : Return();
 } // expected-warning {{control may reach end of non-void function}}