RHBA-2015:1339 - Bug Fix Advisory

Topic

Updated gcc packages that fix several bugs and add one enhancement are now
available for Red Hat Enterprise Linux 6.

Description

The gcc packages provide compilers for C, C++, Java, Fortran, Objective C, and
Ada 95 GNU, as well as related support libraries.

This update fixes the following bugs:

• Previously, due to a bug in the stdarg functions optimization, the compiler

could produce incorrect code. The problem occurred only when the va_list
variable escaped a PHI node. This bug has been fixed, and the compiler now
generates correct code. (BZ#1190640)

• Previously, when the vectorization optimization was enabled, the compiler

could extract a scalar component of a vector with element types whose precision
did not match the precision of their mode. Consequently, GCC could terminate
unexpectedly while trying to vectorize a code that was using bit-fields. With
this update, the compiler no longer vectorizes such code, and the code now
compiles correctly. (BZ#1150606)

• Previously, the compiler did not properly handle incorrect usage of the PCH

(Precompiled Headers) feature. When a PCH file was not included as the first
include, the compiler terminated unexpectedly with a segmentation fault. The
compiler has been fixed not to use such incorrect includes, and it no longer
crashes in this scenario. (BZ#1177458)

• In previous versions of the GNU Fortran compiler, the type specifiers for Cray

pointees were incorrectly overwritten by the type specifiers of components with
the same name. Consequently, compiling failed with an error message. This bug
has been fixed, and the Cray pointers are now handled correctly. (BZ#1134560)

In addition, this update adds the following enhancement:

• The gcc hotpatch attribute implements support for online patching of

multithreaded code on System z binaries. With this update, it is possible to
select specific functions for hotpatching using a "function attribute" and to
enable hotpatching for all functions using the "-mhotpatch=" command-line
option. As enabled hotpatching has negative impact on software size and
performance, it is recommended to use hotpatching for specific functions and not
to enable hotpatch support in general. (BZ#1148120)

Users of gcc are advised to upgrade to these updated packages, which fix these
bugs and add this enhancement.

Solution

Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 1134560 - Component declarations overwrite types of Cray Pointee variables
• BZ - 1150606 - summing bitfield generates invalid code(using sse2 in -O3)
• BZ - 1177458 - cc1plus: internal compiler error: Segmentation fault

CVEs

(none)

References

(none)