Technical data

Compiler Commands [2]
2.13 Scalar Optimization Options
The following sections describe scalar optimization options.
2.13.1 -h [no]interchange (CC, cc)
Default option: -h interchange
The -h interchange option instructs the compiler to attempt to interchange all
loops, a technique that is used to gain performance by having the compiler swap
an inner loop with an outer loop. The compiler attempts the interchange only if
the interchange will increase performance. Loop interchange is performed only at
scalar optimization level 2 or higher.
The -h nointerchange option prevents the compiler from attempting to
interchange any loops. To disable interchange of loops individually, use the
#pragma nointerchange directive.
2.13.2 -h scalarn (CC, cc)
Default option: -h scalar1
The -h scalarn option specifies the level of automatic scalar optimization to
be performed. Scalar optimization directives are unaffected by this option (see
Section 3.10, page 86).
Argument n can be one of the following:
n
Description
0 No automatic scalar optimization. The -h nobl,
-h nofastfpdivide, -h nofastmd, -h nofastmodulus,
-h matherror=errno, and -h zeroinc options are implied by
-h scalar0.
1 Conservative automatic scalar optimization. This level implies
-h fastmd, -h fastfpdivide, -h matherror=abort,
and -h nozeroinc and causes automatic loop alignment to
be performed.
2 Moderate automatic scalar optimization. The scalar optimizations
specified by scalar1 are performed.
3 Aggressive automatic scalar optimization. The scalar optimizations
specified by scalar2 are performed and -h fastmodulus
and -h bl are implied.
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