http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55981
Bug #: 55981
Summary: std::atomic store is split in two smaller stores
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
AssignedTo: [email protected]
ReportedBy: [email protected]
Created attachment 29166
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29166
miscompiled program
Hi,
in the attached program, std::atomic<unsigned long> store is compiled as two
4-byte stores, becoming not atomic at all. This happens at -O2 and higher.
To reproduce,
# g++ -std=c++11 -O3 1.cc -lpthread -o 1
# ./1
100000004
^ this can also be 300000002, both outcomes are invalid.
