[libcxx-commits] [libcxx] [libc++] Add parentheses around shift operations in bitwise expressions (PR #175407)
Fady Farag via libcxx-commits
libcxx-commits at lists.llvm.org
Sat Jan 10 20:10:57 PST 2026
https://github.com/iidmsa updated https://github.com/llvm/llvm-project/pull/175407
>From e9a5775a55dc6de3020efa5591cd73690cf03110 Mon Sep 17 00:00:00 2001
From: Fady Farag <com.webkit.iidmsa at gmail.com>
Date: Sat, 10 Jan 2026 21:54:55 -0600
Subject: [PATCH 1/2] [libc++] Add parentheses around shift operations in
bitwise expressions
This makes the intent explicit and improves consistency within
files that already use this style elsewhere.
---
libcxx/include/__bit/byteswap.h | 2 +-
libcxx/src/locale.cpp | 24 ++++++++++++------------
libcxx/test/support/concat_macros.h | 6 +++---
3 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/libcxx/include/__bit/byteswap.h b/libcxx/include/__bit/byteswap.h
index d761e6a6fdb46..7ce7e069b4142 100644
--- a/libcxx/include/__bit/byteswap.h
+++ b/libcxx/include/__bit/byteswap.h
@@ -37,7 +37,7 @@ template <integral _Tp>
# if __has_builtin(__builtin_bswap128)
return __builtin_bswap128(__val);
# else
- return static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val))) << 64 |
+ return (static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val))) << 64) |
static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val >> 64)));
# endif // __has_builtin(__builtin_bswap128)
# endif // _LIBCPP_HAS_INT128
diff --git a/libcxx/src/locale.cpp b/libcxx/src/locale.cpp
index 6be0537735c8f..4d5e681e2556a 100644
--- a/libcxx/src/locale.cpp
+++ b/libcxx/src/locale.cpp
@@ -2318,7 +2318,7 @@ static codecvt_base::result utf16be_to_ucs4(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xFC00) == 0xDC00)
return codecvt_base::error;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2329,7 +2329,7 @@ static codecvt_base::result utf16be_to_ucs4(
} else {
if (frm_end - frm_nxt < 4)
return codecvt_base::partial;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[2] << 8 | frm_nxt[3]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[2] << 8) | frm_nxt[3]);
if ((c2 & 0xFC00) != 0xDC00)
return codecvt_base::error;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2354,7 +2354,7 @@ static int utf16be_to_ucs4_length(
frm_nxt += 2;
}
for (size_t nchar32_t = 0; frm_nxt < frm_end - 1 && nchar32_t < mx; ++nchar32_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xFC00) == 0xDC00)
break;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2364,7 +2364,7 @@ static int utf16be_to_ucs4_length(
} else {
if (frm_end - frm_nxt < 4)
break;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[2] << 8 | frm_nxt[3]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[2] << 8) | frm_nxt[3]);
if ((c2 & 0xFC00) != 0xDC00)
break;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2432,7 +2432,7 @@ static codecvt_base::result utf16le_to_ucs4(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xFC00) == 0xDC00)
return codecvt_base::error;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2443,7 +2443,7 @@ static codecvt_base::result utf16le_to_ucs4(
} else {
if (frm_end - frm_nxt < 4)
return codecvt_base::partial;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[3] << 8 | frm_nxt[2]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[3] << 8) | frm_nxt[2]);
if ((c2 & 0xFC00) != 0xDC00)
return codecvt_base::error;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2468,7 +2468,7 @@ static int utf16le_to_ucs4_length(
frm_nxt += 2;
}
for (size_t nchar32_t = 0; frm_nxt < frm_end - 1 && nchar32_t < mx; ++nchar32_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xFC00) == 0xDC00)
break;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2478,7 +2478,7 @@ static int utf16le_to_ucs4_length(
} else {
if (frm_end - frm_nxt < 4)
break;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[3] << 8 | frm_nxt[2]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[3] << 8) | frm_nxt[2]);
if ((c2 & 0xFC00) != 0xDC00)
break;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2535,7 +2535,7 @@ static codecvt_base::result utf16be_to_ucs2(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
return codecvt_base::error;
*to_nxt = c1;
@@ -2556,7 +2556,7 @@ static int utf16be_to_ucs2_length(
frm_nxt += 2;
}
for (size_t nchar16_t = 0; frm_nxt < frm_end - 1 && nchar16_t < mx; ++nchar16_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
break;
frm_nxt += 2;
@@ -2609,7 +2609,7 @@ static codecvt_base::result utf16le_to_ucs2(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
return codecvt_base::error;
*to_nxt = c1;
@@ -2631,7 +2631,7 @@ static int utf16le_to_ucs2_length(
frm_nxt += 2;
}
for (size_t nchar16_t = 0; frm_nxt < frm_end - 1 && nchar16_t < mx; ++nchar16_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
break;
frm_nxt += 2;
diff --git a/libcxx/test/support/concat_macros.h b/libcxx/test/support/concat_macros.h
index efec4029f4025..39d208c0f3f7b 100644
--- a/libcxx/test/support/concat_macros.h
+++ b/libcxx/test/support/concat_macros.h
@@ -60,7 +60,7 @@ void test_encode(OutIt& out_it, char16_t value) {
*out_it++ = static_cast<char>(0b10000000 | (value & 0b00111111));
} else {
*out_it++ = static_cast<char>(0b11100000 | (value >> 12));
- *out_it++ = static_cast<char>(0b10000000 | ((value) >> 6 & 0b00111111));
+ *out_it++ = static_cast<char>(0b10000000 | ((value >> 6) & 0b00111111));
*out_it++ = static_cast<char>(0b10000000 | (value & 0b00111111));
}
}
@@ -72,8 +72,8 @@ void test_encode(OutIt& out_it, char32_t value) {
test_encode(out_it, static_cast<char16_t>(value));
else {
*out_it++ = static_cast<char>(0b11100000 | (value >> 18));
- *out_it++ = static_cast<char>(0b10000000 | ((value) >> 12 & 0b00111111));
- *out_it++ = static_cast<char>(0b10000000 | ((value) >> 6 & 0b00111111));
+ *out_it++ = static_cast<char>(0b10000000 | ((value >> 12) & 0b00111111));
+ *out_it++ = static_cast<char>(0b10000000 | ((value >> 6) & 0b00111111));
*out_it++ = static_cast<char>(0b10000000 | (value & 0b00111111));
}
}
>From d08f4a2e600b33c0f309092d29ae39bd1313cd8c Mon Sep 17 00:00:00 2001
From: Fady Farag <com.webkit.iidmsa at gmail.com>
Date: Sat, 10 Jan 2026 21:54:55 -0600
Subject: [PATCH 2/2] [libc++] Add parentheses around shift operations in
bitwise expressions
This makes the intent explicit and improves consistency within
files that already use this style.
---
libcxx/include/__bit/byteswap.h | 2 +-
libcxx/src/locale.cpp | 24 ++++++++++++------------
libcxx/test/support/concat_macros.h | 6 +++---
3 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/libcxx/include/__bit/byteswap.h b/libcxx/include/__bit/byteswap.h
index d761e6a6fdb46..7ce7e069b4142 100644
--- a/libcxx/include/__bit/byteswap.h
+++ b/libcxx/include/__bit/byteswap.h
@@ -37,7 +37,7 @@ template <integral _Tp>
# if __has_builtin(__builtin_bswap128)
return __builtin_bswap128(__val);
# else
- return static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val))) << 64 |
+ return (static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val))) << 64) |
static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val >> 64)));
# endif // __has_builtin(__builtin_bswap128)
# endif // _LIBCPP_HAS_INT128
diff --git a/libcxx/src/locale.cpp b/libcxx/src/locale.cpp
index 6be0537735c8f..4d5e681e2556a 100644
--- a/libcxx/src/locale.cpp
+++ b/libcxx/src/locale.cpp
@@ -2318,7 +2318,7 @@ static codecvt_base::result utf16be_to_ucs4(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xFC00) == 0xDC00)
return codecvt_base::error;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2329,7 +2329,7 @@ static codecvt_base::result utf16be_to_ucs4(
} else {
if (frm_end - frm_nxt < 4)
return codecvt_base::partial;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[2] << 8 | frm_nxt[3]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[2] << 8) | frm_nxt[3]);
if ((c2 & 0xFC00) != 0xDC00)
return codecvt_base::error;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2354,7 +2354,7 @@ static int utf16be_to_ucs4_length(
frm_nxt += 2;
}
for (size_t nchar32_t = 0; frm_nxt < frm_end - 1 && nchar32_t < mx; ++nchar32_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xFC00) == 0xDC00)
break;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2364,7 +2364,7 @@ static int utf16be_to_ucs4_length(
} else {
if (frm_end - frm_nxt < 4)
break;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[2] << 8 | frm_nxt[3]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[2] << 8) | frm_nxt[3]);
if ((c2 & 0xFC00) != 0xDC00)
break;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2432,7 +2432,7 @@ static codecvt_base::result utf16le_to_ucs4(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xFC00) == 0xDC00)
return codecvt_base::error;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2443,7 +2443,7 @@ static codecvt_base::result utf16le_to_ucs4(
} else {
if (frm_end - frm_nxt < 4)
return codecvt_base::partial;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[3] << 8 | frm_nxt[2]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[3] << 8) | frm_nxt[2]);
if ((c2 & 0xFC00) != 0xDC00)
return codecvt_base::error;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2468,7 +2468,7 @@ static int utf16le_to_ucs4_length(
frm_nxt += 2;
}
for (size_t nchar32_t = 0; frm_nxt < frm_end - 1 && nchar32_t < mx; ++nchar32_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xFC00) == 0xDC00)
break;
if ((c1 & 0xFC00) != 0xD800) {
@@ -2478,7 +2478,7 @@ static int utf16le_to_ucs4_length(
} else {
if (frm_end - frm_nxt < 4)
break;
- uint16_t c2 = static_cast<uint16_t>(frm_nxt[3] << 8 | frm_nxt[2]);
+ uint16_t c2 = static_cast<uint16_t>((frm_nxt[3] << 8) | frm_nxt[2]);
if ((c2 & 0xFC00) != 0xDC00)
break;
uint32_t t = static_cast<uint32_t>(((((c1 & 0x03C0) >> 6) + 1) << 16) | ((c1 & 0x003F) << 10) | (c2 & 0x03FF));
@@ -2535,7 +2535,7 @@ static codecvt_base::result utf16be_to_ucs2(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
return codecvt_base::error;
*to_nxt = c1;
@@ -2556,7 +2556,7 @@ static int utf16be_to_ucs2_length(
frm_nxt += 2;
}
for (size_t nchar16_t = 0; frm_nxt < frm_end - 1 && nchar16_t < mx; ++nchar16_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[0] << 8) | frm_nxt[1]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
break;
frm_nxt += 2;
@@ -2609,7 +2609,7 @@ static codecvt_base::result utf16le_to_ucs2(
frm_nxt += 2;
}
for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
return codecvt_base::error;
*to_nxt = c1;
@@ -2631,7 +2631,7 @@ static int utf16le_to_ucs2_length(
frm_nxt += 2;
}
for (size_t nchar16_t = 0; frm_nxt < frm_end - 1 && nchar16_t < mx; ++nchar16_t) {
- uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+ uint16_t c1 = static_cast<uint16_t>((frm_nxt[1] << 8) | frm_nxt[0]);
if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
break;
frm_nxt += 2;
diff --git a/libcxx/test/support/concat_macros.h b/libcxx/test/support/concat_macros.h
index efec4029f4025..39d208c0f3f7b 100644
--- a/libcxx/test/support/concat_macros.h
+++ b/libcxx/test/support/concat_macros.h
@@ -60,7 +60,7 @@ void test_encode(OutIt& out_it, char16_t value) {
*out_it++ = static_cast<char>(0b10000000 | (value & 0b00111111));
} else {
*out_it++ = static_cast<char>(0b11100000 | (value >> 12));
- *out_it++ = static_cast<char>(0b10000000 | ((value) >> 6 & 0b00111111));
+ *out_it++ = static_cast<char>(0b10000000 | ((value >> 6) & 0b00111111));
*out_it++ = static_cast<char>(0b10000000 | (value & 0b00111111));
}
}
@@ -72,8 +72,8 @@ void test_encode(OutIt& out_it, char32_t value) {
test_encode(out_it, static_cast<char16_t>(value));
else {
*out_it++ = static_cast<char>(0b11100000 | (value >> 18));
- *out_it++ = static_cast<char>(0b10000000 | ((value) >> 12 & 0b00111111));
- *out_it++ = static_cast<char>(0b10000000 | ((value) >> 6 & 0b00111111));
+ *out_it++ = static_cast<char>(0b10000000 | ((value >> 12) & 0b00111111));
+ *out_it++ = static_cast<char>(0b10000000 | ((value >> 6) & 0b00111111));
*out_it++ = static_cast<char>(0b10000000 | (value & 0b00111111));
}
}
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