[libc-commits] [libc] [libc] implement `memalignment` (PR #132493)

[Joseph Huber via libc-commits]

================
@@ -0,0 +1,19 @@
+#include "src/stdlib/memalignment.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, memalignment, (const void *p)) {
+  if (p == NULL) {
+    return 0;
+  }
+
+  uintptr_t addr = (uintptr_t)p;
+
+  // Find the rightmost set bit, which represents the maximum alignment
+  // The alignment is a power of two, so we need to find the largest
+  // power of two that divides the address
+  return addr & (~addr + 1);
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jhuber6 wrote:

No, the opposite.

https://github.com/llvm/llvm-project/pull/132493