From 83e2403545fe968cb01d53f0cb3b511efc841cbb Mon Sep 17 00:00:00 2001
From: Rostyslav Geyyer <46627076+geyyer@users.noreply.github.com>
Date: Thu, 18 Sep 2025 09:12:37 -0500
Subject: [PATCH] Fix UB caused by reinterpret_cast (#2849)

* Use bit_cast instead of reinterpret_cast to avoid UB

* Apply same fix in ck_tile

[ROCm/composable_kernel commit: 14bbc545ea672e66cdce00a3edbf4c532e2657e8]
---
 include/ck/utility/random_gen.hpp       | 5 +++--
 include/ck_tile/core/utility/random.hpp | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/ck/utility/random_gen.hpp b/include/ck/utility/random_gen.hpp
index c37d3922ca..2ff46457fc 100644
--- a/include/ck/utility/random_gen.hpp
+++ b/include/ck/utility/random_gen.hpp
@@ -3,6 +3,7 @@
 
 #pragma once
 #include <ck/utility/ignore.hpp>
+#include <ck/utility/type.hpp>
 #include "ck/ck.hpp"
 
 #ifdef CK_CODE_GEN_RTC
@@ -17,7 +18,7 @@ namespace ck {
 template <typename T, uint32_t seed_t, ck::enable_if_t<std::is_same<float, T>{}, bool> = false>
 __host__ __device__ uint32_t prand_generator(index_t id, T val, uint32_t seed = seed_t)
 {
-    uint32_t x         = *(reinterpret_cast<uint32_t*>(&val));
+    uint32_t x         = bit_cast<uint32_t>(val);
     uint32_t drop_bits = uint32_t(x) & 0xFFFFu;
     drop_bits ^= x >> 16;
     drop_bits = ((drop_bits & 31) << 11) | (drop_bits >> 5);
@@ -33,7 +34,7 @@ __host__ __device__ uint32_t prand_generator(index_t id, T val, uint32_t seed =
 template <typename T, uint32_t seed_t, ck::enable_if_t<std::is_same<_Float16, T>{}, bool> = false>
 __host__ __device__ uint32_t prand_generator(index_t id, T val, uint32_t seed = seed_t)
 {
-    uint16_t x         = *(reinterpret_cast<uint16_t*>(&val));
+    uint16_t x         = bit_cast<uint16_t>(val);
     uint32_t drop_bits = uint32_t(x) & 0xFFFFu;
     drop_bits          = ((drop_bits & 31) << 11) | (drop_bits >> 5);
     drop_bits *= 0x7000149;
diff --git a/include/ck_tile/core/utility/random.hpp b/include/ck_tile/core/utility/random.hpp
index f7fbfad4dd..6a38ad3bde 100644
--- a/include/ck_tile/core/utility/random.hpp
+++ b/include/ck_tile/core/utility/random.hpp
@@ -24,7 +24,7 @@ struct prand_generator_t<float, seed_>
 {
     CK_TILE_HOST_DEVICE uint32_t operator()(int id, float val, uint32_t seed = seed_)
     {
-        uint32_t x         = *(reinterpret_cast<uint32_t*>(&val));
+        uint32_t x         = bit_cast<uint32_t>(val);
         uint32_t drop_bits = uint32_t(x) & 0xFFFFu;
         drop_bits ^= x >> 16;
         drop_bits = ((drop_bits & 31) << 11) | (drop_bits >> 5);
@@ -43,7 +43,7 @@ struct prand_generator_t<half_t, seed_>
 {
     CK_TILE_HOST_DEVICE uint32_t operator()(int id, half_t val, uint32_t seed = seed_)
     {
-        uint16_t x         = *(reinterpret_cast<uint16_t*>(&val));
+        uint16_t x         = bit_cast<uint16_t>(val);
         uint32_t drop_bits = uint32_t(x) & 0xFFFFu;
         drop_bits          = ((drop_bits & 31) << 11) | (drop_bits >> 5);
         drop_bits *= 0x7000149;