[llvm-branch-commits] [clang] release/19.x: [Clang][CodeGen] Don't emit assumptions if current block is unreachable. (#106936) (PR #107183)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-clang

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport c94bd96c277e0b48e198fdc831bb576d9a04aced

Requested by: @<!-- -->dtcxzyw

---
Full diff: https://github.com/llvm/llvm-project/pull/107183.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/CGStmt.cpp (+1-1) 
- (modified) clang/test/SemaCXX/cxx23-assume.cpp (+9) 


``````````diff
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index aa97f685ac7a9f..2f466602d2f680 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -745,7 +745,7 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
     } break;
     case attr::CXXAssume: {
       const Expr *Assumption = cast<CXXAssumeAttr>(A)->getAssumption();
-      if (getLangOpts().CXXAssumptions &&
+      if (getLangOpts().CXXAssumptions && Builder.GetInsertBlock() &&
           !Assumption->HasSideEffects(getContext())) {
         llvm::Value *AssumptionVal = EvaluateExprAsBool(Assumption);
         Builder.CreateAssumption(AssumptionVal);
diff --git a/clang/test/SemaCXX/cxx23-assume.cpp b/clang/test/SemaCXX/cxx23-assume.cpp
index 9138501d726dd6..eeae59daea3f70 100644
--- a/clang/test/SemaCXX/cxx23-assume.cpp
+++ b/clang/test/SemaCXX/cxx23-assume.cpp
@@ -158,3 +158,12 @@ foo (int x, int y)
   return x + y;
 }
 }
+
+// Do not crash when assumptions are unreachable.
+namespace gh106898 {
+int foo () { 
+    while(1);
+    int a = 0, b = 1;
+    __attribute__((assume (a < b)));
+}
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/107183