[clang] [clang][CodeGen] fix UB in aarch64 bfloat16 scalar conversion (PR #89062)

[via cfe-commits]

https://github.com/nihui updated https://github.com/llvm/llvm-project/pull/89062

>From 05461899522816d2569fdab73b9eeda525524cc8 Mon Sep 17 00:00:00 2001
From: nihui <shuizhuyuanluo at 126.com>
Date: Wed, 17 Apr 2024 20:04:00 +0800
Subject: [PATCH] fix UB in bfloat16 scalar conversion

---
 clang/include/clang/Basic/arm_neon.td | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/arm_neon.td b/clang/include/clang/Basic/arm_neon.td
index 6d655c39360d3b..6390ba3f9fe5e5 100644
--- a/clang/include/clang/Basic/arm_neon.td
+++ b/clang/include/clang/Basic/arm_neon.td
@@ -275,7 +275,7 @@ def OP_VCVT_BF16_F32_HI_A32
                            (call "vget_low", $p0))>;
 
 def OP_CVT_F32_BF16
-    : Op<(bitcast "R", (op "<<", (bitcast "int32_t", $p0),
+    : Op<(bitcast "R", (op "<<", (cast "int32_t", (bitcast "int16_t", $p0)),
                                  (literal "int32_t", "16")))>;
 
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