[llvm] [Bitcode] Fix a signed integer overflow in BitstreamWriter.h (PR #75213)

[via llvm-commits]

https://github.com/MaggieYingYi updated https://github.com/llvm/llvm-project/pull/75213

>From 45a019e15e1b7661dbbc94e1578fededf46493ba Mon Sep 17 00:00:00 2001
From: Ying Yi <ying.yi at sony.com>
Date: Tue, 12 Dec 2023 12:13:47 +0000
Subject: [PATCH] Fixed a signed integer overflow in BitstreamWriter.h which is
 found by UBSAN.

---
 llvm/include/llvm/Bitstream/BitstreamWriter.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/llvm/include/llvm/Bitstream/BitstreamWriter.h b/llvm/include/llvm/Bitstream/BitstreamWriter.h
index f7d362b5d70ceb..c726508cd52851 100644
--- a/llvm/include/llvm/Bitstream/BitstreamWriter.h
+++ b/llvm/include/llvm/Bitstream/BitstreamWriter.h
@@ -239,7 +239,8 @@ class BitstreamWriter {
 
     // Emit the bits with VBR encoding, NumBits-1 bits at a time.
     while (Val >= Threshold) {
-      Emit((Val & ((1 << (NumBits-1))-1)) | (1 << (NumBits-1)), NumBits);
+      Emit((Val & ((1U << (NumBits - 1)) - 1)) | (1U << (NumBits - 1)),
+           NumBits);
       Val >>= NumBits-1;
     }
 
@@ -255,7 +256,8 @@ class BitstreamWriter {
 
     // Emit the bits with VBR encoding, NumBits-1 bits at a time.
     while (Val >= Threshold) {
-      Emit(((uint32_t)Val & ((1 << (NumBits - 1)) - 1)) | (1 << (NumBits - 1)),
+      Emit(((uint32_t)Val & ((1U << (NumBits - 1)) - 1)) |
+               (1U << (NumBits - 1)),
            NumBits);
       Val >>= NumBits-1;
     }