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GCC - loop optimizations

+2 votes
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I want to use some loop optimizations. I have build GCC-4.8.1 using gmp 5.1.3, mpfr 3.1.2, mpc 1.0.1, cloog 0.18.0 and isl 0.11.1. I tried optimization flags -floop-interchange and -floop-block. I don't find any changes in the optimized code.

Are graphite loop transforms implemented in GCC-4.8.1. Should I configure and build GCC in a different way.

posted Nov 29, 2013 by Mandeep Sehgal

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1 Answer

+1 vote

Are graphite loop transforms implemented in GCC-4.8.1.

Yes.

Should I configure and build GCC in a different way.

You didn't say how you configured it, so noone can say if you need to do it differently.

answer Nov 30, 2013 by Sonu Jindal
I have used the following configuration

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/gcc/libexec/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc_4_8_1/configure --prefix=/opt/gcc --with-gmp=/opt/gmp-5.1.3 --with-mpfr=/opt/mpfr-3.1.2 --with-mpc=/opt/mpc-1.0.1 --enable-languages=c,c++ --with-cloog=/opt/cloog-0.18.0 --with-isl=/opt/isl-0.11.1
Thread model: posix
gcc version 4.8.1 (GCC)

I tried using using -floop-block and -floop-interchange optimization flags on simple program with for loops. I don't find any difference in the optimized assembly code that is generated. I have enabled O1
optimization level and disabled all the flags. I have only enabled -floop-block and -floop-interchange. Should I enable any more options for this to work?
commented Nov 30, 2013 by anonymous
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