[clang] ef20644 - [clang] Warn const integer-overflow of member in temporary struct bound to rvalue reference (#117225)

[via cfe-commits]

Author: Youngsuk Kim
Date: 2024-11-22T04:51:09-05:00
New Revision: ef206446f2bbcb1bacc73d7611a96c457f59499f

URL: https://github.com/llvm/llvm-project/commit/ef206446f2bbcb1bacc73d7611a96c457f59499f
DIFF: https://github.com/llvm/llvm-project/commit/ef206446f2bbcb1bacc73d7611a96c457f59499f.diff

LOG: [clang] Warn const integer-overflow of member in temporary struct bound to rvalue reference (#117225)

Fixes #46755

---------

Co-authored-by: Sirraide <aeternalmail at gmail.com>

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/SemaChecking.cpp
    clang/test/SemaCXX/integer-overflow.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 4847437ef1f8bd..54145b28154eb4 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -580,6 +580,9 @@ Improvements to Clang's diagnostics
 
 - Improved error recovery for function call arguments with trailing commas (#GH100921).
 
+- For an rvalue reference bound to a temporary struct with an integer member, Clang will detect constant integer overflow
+  in the initializer for the integer member (#GH46755).
+
 Improvements to Clang's time-trace
 ----------------------------------
 

diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 2fd990750ed212..a49605e4867651 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -12048,7 +12048,8 @@ void Sema::CheckForIntOverflow (const Expr *E) {
              New && New->isArray()) {
       if (auto ArraySize = New->getArraySize())
         Exprs.push_back(*ArraySize);
-    }
+    } else if (const auto *MTE = dyn_cast<MaterializeTemporaryExpr>(OriginalE))
+      Exprs.push_back(MTE->getSubExpr());
   } while (!Exprs.empty());
 }
 

diff  --git a/clang/test/SemaCXX/integer-overflow.cpp b/clang/test/SemaCXX/integer-overflow.cpp
index d1cc8bee566f6b..73a4e88ee6c098 100644
--- a/clang/test/SemaCXX/integer-overflow.cpp
+++ b/clang/test/SemaCXX/integer-overflow.cpp
@@ -246,4 +246,10 @@ int m() {
     return 0;
 }
 }
+
+namespace GH46755 {
+void f() {
+    struct { int v; } &&r = {512 * 1024 * 1024 * 1024}; // expected-warning {{overflow in expression; result is 0 with type 'int'}}
+}
+}
 #endif