Joe McDonnell has uploaded this change for review. ( 
http://gerrit.cloudera.org:8080/21721


Change subject: IMPALA-13308: Build GCC with profile guided optimization
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IMPALA-13308: Build GCC with profile guided optimization

GCC has an option to build itself using profile guided
optimization. It collects a profile while building itself
and then uses that to optimize the binary. This seems to
be enough to speed up Impala compilation by about 5%:

Current toolchain GCC (LTO):
real    4m58.416s
user    70m41.989s
sys     6m41.961s

GCC with PGO, no LTO:
real    4m45.360s
user    67m12.081s
sys     6m40.376s

LTO shows little improvement over the PGO numbers, so this
switches back to a non-LTO build to save build time. Avoiding
LTO and using a slightly faster GCC reduces the total build
time by 35 minutes on an internal job.

Testing:
 - Ran a build, then used it to build Impala

Change-Id: I9f5850999b05207ddc008d839de2783579eaaf31
---
M source/gcc/build.sh
1 file changed, 3 insertions(+), 2 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/native-toolchain 
refs/changes/21/21721/1
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Gerrit-Project: native-toolchain
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I9f5850999b05207ddc008d839de2783579eaaf31
Gerrit-Change-Number: 21721
Gerrit-PatchSet: 1
Gerrit-Owner: Joe McDonnell <[email protected]>

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