[libc][NFC] Selectively disable GCC warnings (#78462)

Author: gchatelet

libc/src/string/memory_utils/op_x86.h

@@ -116,6 +116,14 @@ LIBC_INLINE MemcmpReturnType cmp_neq<uint64_t>(CPtr p1, CPtr p2,
   return cmp_neq_uint64_t(a, b);
 }
 
+// SIMD types are defined with attributes. e.g., '__m128i' is defined as
+// long long  __attribute__((__vector_size__(16), __aligned__(16)))
+// When we use these SIMD types in template specialization GCC complains:
+// "ignoring attributes on template argument ‘__m128i’ [-Wignored-attributes]"
+// Therefore, we disable this warning in this file.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wignored-attributes"
+
 ///////////////////////////////////////////////////////////////////////////////
 // Specializations for __m128i
 #if defined(__SSE4_1__)
@@ -304,6 +312,8 @@ LIBC_INLINE MemcmpReturnType cmp_neq<__m512i>(CPtr p1, CPtr p2, size_t offset) {
 }
 #endif // __AVX512BW__
 
+#pragma GCC diagnostic pop
+
 } // namespace LIBC_NAMESPACE::generic
 
 #endif // LIBC_TARGET_ARCH_IS_X86_64

libc/src/string/memory_utils/utils.h

@@ -89,9 +89,11 @@ LIBC_INLINE void memcpy_inline(void *__restrict dst,
   // In memory functions `memcpy_inline` is instantiated several times with
   // different value of the Size parameter. This doesn't play well with GCC's
   // Value Range Analysis that wrongly detects out of bounds accesses. We
-  // disable the 'array-bounds' warning for the purpose of this function.
+  // disable these warnings for the purpose of this function.
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Warray-bounds"
+#pragma GCC diagnostic ignored "-Wstringop-overread"
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
   for (size_t i = 0; i < Size; ++i)
     static_cast<char *>(dst)[i] = static_cast<const char *>(src)[i];
 #pragma GCC diagnostic pop