[llvm] 6a5dd04 - [Support] Try to fix AlignedCharArrayUnion with GCC 7.5

[Jonas Hahnfeld via llvm-commits]

Author: Jonas Hahnfeld
Date: 2025-02-25T21:35:01+01:00
New Revision: 6a5dd04013a1442ed4c5861216c8c67a81f37ed0

URL: https://github.com/llvm/llvm-project/commit/6a5dd04013a1442ed4c5861216c8c67a81f37ed0
DIFF: https://github.com/llvm/llvm-project/commit/6a5dd04013a1442ed4c5861216c8c67a81f37ed0.diff

LOG: [Support] Try to fix AlignedCharArrayUnion with GCC 7.5

Work around "internal compiler error: Segmentation fault", apparently
caused by alignas(Ts...).

Added: 
    

Modified: 
    llvm/include/llvm/Support/AlignOf.h

Removed: 
    


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diff  --git a/llvm/include/llvm/Support/AlignOf.h b/llvm/include/llvm/Support/AlignOf.h
index 635bb8b101ef9..4f02e81dba151 100644
--- a/llvm/include/llvm/Support/AlignOf.h
+++ b/llvm/include/llvm/Support/AlignOf.h
@@ -20,7 +20,10 @@ namespace llvm {
 /// A suitably aligned and sized character array member which can hold elements
 /// of any type.
 template <typename T, typename... Ts> struct AlignedCharArrayUnion {
-  alignas(T) alignas(Ts...) char buffer[std::max({sizeof(T), sizeof(Ts)...})];
+  // Work around "internal compiler error: Segmentation fault" with GCC 7.5,
+  // apparently caused by alignas(Ts...).
+  static constexpr std::size_t Align = std::max({alignof(T), alignof(Ts)...});
+  alignas(Align) char buffer[std::max({sizeof(T), sizeof(Ts)...})];
 };
 
 } // end namespace llvm