http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50189
Bug #: 50189
Summary: Wrong code error in -O2 compile, target independent
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c++
AssignedTo: [email protected]
ReportedBy: [email protected]
Created attachment 25105
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25105
Test program
The attached test program compiles to wrong code with GCC 4.5.3 (and 4.5.1)
when compiled -O2. GCC 4.6.1 gets it right.
I did some digging and determined that the problem shows up in the
-fdump-tree-all output in the .068t.vrp1 dump file; the preceding file
(.067.mergephi2) is correct. In the generated code that corresponds to the
check_pos method, the second compare "if (m_timestamp != a_timestamp)" is
transformed into "if (3 == a_timestamp)". If m_timestamp were of time
position_t (an enum of range 0..3) that would be correct, but m_timestamp is an
unsigned int so it can, and in our application does, have values larger than 3.
