Selective Use of gatherhint/scatterhint Instructions
Compiler Methodology for Intel® MIC ArchitectureSelective Use of gatherhint/scatterhint InstructionsOverviewThe -mGLOB_default_function_attrs=”use_gather_scatter_hint=on” compiler option can be used to...
View ArticleAdvanced Optimizations for Intel® MIC Architecture, Low Precision Optimizations
Compiler Methodology for Intel® MIC Architecture Advanced Optimizations for Intel® MIC Architecture, Low Precision OptimizationsOverviewThe latest Intel Compilers (released after the 13.0.039 Beta...
View ArticleAdvanced Optimizations for Intel® MIC Architecture
Compiler Methodology for Intel® MIC ArchitectureAdvanced OptimizationsOverviewThis chapter details some of the advanced compiler optimizations for performance on Intel® MIC Architecture AND most of...
View ArticleGetting Started with Intel® Composer XE 2013, Compiler Pragmas and Directives
Compiler Methodology for Intel® MIC Architecture Getting Started with Intel® Composer XE 2013, Compiler Pragmas and DirectivesOverviewCompiler options allow a user to control how source files are...
View ArticleExpectations for User Source Code Changes
OverviewAlthough most codes can run in the Intel® Many Integrated Core Architecture (Intel® MIC Architecture) with little to no changes, to run EFFICIENTLY may require changes in user source code. This...
View ArticleMemory Layout Transformations
Compiler Methodology for Intel® MIC ArchitectureMemory Layout TransformationsOverviewThis chapter examines a useful user code transformation: moving from data organized in an Array of Structures (AoS)...
View ArticleQERFC may return incorrect results if floating-point exceptions are unmasked
Reference Number : dpd200178477Version : Intel® Fortran Compiler Versions 12, 13 and 14.Operating System : Windows*, Linux*, OS X*Problem Description : For certain values of the argument, the result of...
View Article/Qopenmp-threadprivate:compat doesn't work with uninitialized threadprivate...
Reference Number : dpd200246096Version : Intel® Fortran Compiler Versions 12, 13 and 14.Operating System : Windows*Problem Description : The /Qopenmp-threadprivate:compat option may not create...
View Article使用Intel® Fortran编译器编译Coarray程序
Coarray是在Fortran 2008中实现标准化的一种数据共享概念， 它通过使用同一个程序的多个拷贝来实现并行处理。这里的每一个拷贝，也被称image，同时拥有普通局部变量和叫做coarray的共享变量。一个共享变量既可以是一个数组也可以是一个标量，它的存储空间会跨越一个程序对应的所有image。在这种分区全局地址空间(Partitioned Global Address Space –...
View Article常见的向量化技巧
面向英特尔® MIC 架构的编译器方法本文收集了关于向量化的各种技巧： 在向量循环中处理用户定义的函数调用如果您希望对具有用户定义的函数调用的循环进行向量化处理，（可能要重建代码）请将函数调用作为向量基本函数。在基本函数中指定单位步长访问如果您的基本函数访问单位步长中的内存，您可以通过两种方式来编写：· 线性整数对统一指针进行索引·...
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Intel Vectorization Toolkit: 3. Determine Loop Candidates Using Intel...
---------------------------------------------------------------------------------------Back to the 6-step Process for Vectorization...
View ArticleVectorization Essentials
Compiler Methodology for Intel® MIC Architecture Vectorization Essentials OverviewThis chapter covers topics in vectorization. Vectorization is a form of data-parallel programming. In this, the...
View ArticleDiagnostic 15043: loop was not vectorized: nonstandard loop is not a...
Causes:1. More than one exit point in the loop. A loop must have a single entry and a single exit point. Multiple exit points in a loop can cause this message. 2. An iteration count that is data...
View ArticleDiagnostic 15046: loop was not vectorized: existence of vector dependence...
Cause: The compiler has detected a potential backward dependency between loop iterations that could make vectorization unsafe. The compiler will not auto-vectorize a loop if there are any data values...
View ArticleDiagnostic 15037: loop was not vectorized: vectorization possible but seems...
This diagnostic can also occur in the form: remainder loop was not vectorized: vectorization possible but seems inefficientCause:The compiler only auto-vectorizes a loop if its internal heuristics...
View ArticleDiagnostic 15032: loop was not vectorized: unsupported reduction (Fortran)
Cause:Reduction idioms can be recognized by the compiler and vectorized in simple cases.The compiler is unable to vectorize more complex constructs and emits a warning message:Example: integer function...
View ArticleDiagnostic 15033: loop was not vectorized: modifying order of operation not...
Cause:A summation operation or reduction can be vectorized by breaking it up into a separate partial sum for each vector lane, and then adding together the partial sums at the end. Because this changes...
View ArticleDiagnostic 15011: loop was not vectorized: statement cannot be vectorized...
Cause:The loop contains a statement that cannot be mapped to SIMD instructions by the vectorizer. In the example below, the loop contains an assignment to a derived data type which is not directly...
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Doctor Fortran in "It's a Modern Fortran World"
I recently received a copy of "Numerical Computing with Modern Fortran", by Richard Hanson and Tim Hopkins, and noted how many books on Fortran are being published recently with "Modern Fortran" in the...
View ArticleDiagnostic 15033: loop was not vectorized: modifying order of operation not...
Cause:A summation operation or reduction can be vectorized by breaking it up into a separate partial sum for each vector lane, and then adding together the partial sums at the end. Because this changes...
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