Developer Guide and Reference

Contents

GAP Message (Diagnostic ID 30533)

Message

Compile with the %s option to vectorize and/or parallelize the loop at line %d.

Advice

Use the
[q or Q]opt-subscript-in-range
option for the specified file during compilation.
This option helps the compiler vectorize and parallelize the loop at the specified line. You must verify that the loops in the file do not contain very large integers and are not likely to generate very large integers in intermediate computations. A very large integer is loosely defined as follows: On an
n
-bit machine, a very large integer is typically >= 2
n-2
. For example, on a 32-bit machine, a very large integer would be >= 2
30
.
Example
Consider the following:
int f(int* A, int upper1, int upper2){ long extra = 100.0; int return_val = 0; int val; for(int j=0; j < upper1; j++){ for(int i = 0; i < upper2; i++){ val = A[i*extra]; return_val += val; } } return return_val; }
If you determine it is safe to do so, compiling this example with the
[q or Q]opt-subscript-in-range
option results in vectorization of the innermost loop.

Verify

Confirm that no loop in the program contains or generates very large integers (typically very large integers are >= 2
30
).

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804