From: Jonathan Wakely <jwakely@redhat.com>
Date: Thu, 8 Feb 2024 15:47:19 +0000 (+0000)
Subject: libstdc++: Remove redundant zeroing in std::bitset::operator>>= [PR113806]
X-Git-Tag: basepoints/gcc-15~1136
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bf883e6428a545d091319c8b71fcfb35e7dd7084;p=thirdparty%2Fgcc.git

libstdc++: Remove redundant zeroing in std::bitset::operator>>= [PR113806]

The unused bits in the high word are already zero before this operation.
Shifting the used bits to the right cannot affect the unused bits, so we
don't need to sanitize them.

libstdc++-v3/ChangeLog:

	PR libstdc++/113806
	* include/std/bitset (bitset::operator>>=): Remove redundant
	call to _M_do_sanitize.
---

diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index 16c4040f532f..ccd6d19f7a40 100644
--- a/libstdc++-v3/include/std/bitset
+++ b/libstdc++-v3/include/std/bitset
@@ -1094,10 +1094,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       operator>>=(size_t __position) _GLIBCXX_NOEXCEPT
       {
 	if (__builtin_expect(__position < _Nb, 1))
-	  {
-	    this->_M_do_right_shift(__position);
-	    this->_M_do_sanitize();
-	  }
+	  this->_M_do_right_shift(__position);
 	else
 	  this->_M_do_reset();
 	return *this;