Tutorial: Using Auto Vectorization with Intel® Fortran Compiler

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ID 758497
Date 4/11/2022
Public
Document Table of Contents
Document Table of Contents x
Tutorial: Using Auto Vectorization Overview
Tutorial: Using Auto Vectorization Overview x
Introduction to Auto Vectorization Tutorial: Linux* and macOS* Tutorial: Windows* Version Additional Exercises Notices and Disclaimers
Tutorial: Linux* and macOS* x
Preparing the Sample Application Establishing a Performance Baseline Generating a Vectorization Report Improving Performance by Aligning Data Improving Performance with Interprocedural Optimization
Tutorial: Windows* Version x
Preparing the Sample Application Establishing a Performance Baseline Generating a Vectorization Report Improving Performance by Aligning Data Improving Performance with Interprocedural Optimization
Tutorial: Using Auto Vectorization Overview

Improving Performance with Interprocedural Optimization

The compiler may be able to perform additional optimizations if it is able to optimize across source line boundaries. These may include, but are not limited to, function inlining. This is enabled with the -ipo option.

Recompile the program using the -ipo option to enable interprocedural optimization.

ifort -real-size 64 -qopt-report=2 -qopt-report-phase=vec -D ALIGNED -ipo matvec.f90 driver.f90 -o MatVector

Note that the vectorization messages now appear at the point of inlining in driver.f90 (line 70) and this is found in the file ipo_out.optrpt. 

LOOP BEGIN at driver.f90(73,16)
   remark #15541: loop was not vectorized: inner loop was already vectorized

   LOOP BEGIN at matvec.f90(32,3) inlined into driver.f90(70,14)
      remark #15398: loop was not vectorized: loop was transformed to memset or memcpy
   LOOP END

   LOOP BEGIN at matvec.f90(33,3) inlined into driver.f90(70,14)
      remark #15541: loop was not vectorized: inner loop was already vectorized

      LOOP BEGIN at matvec.f90(38,6) inlined into driver.f90(70,14)
         remark #15399: vectorization support: unroll factor set to 4
         remark #15300: LOOP WAS VECTORIZED
      LOOP END
   LOOP END
LOOP END

NOTE:
Your line and column numbers may be different.

Now, run the executable and record the execution time.

Parent topic: Tutorial: Linux* and macOS* Version
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