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

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

[Jonathan Wakely]

Tested aarch64-linux and x86_64-linux. Pushed to trunk.

-- >8 --

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.
---
 libstdc++-v3/include/std/bitset | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index 16c4040f532..ccd6d19f7a4 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;
-- 
2.43.0