strict

Syntax

    -qstrict | -qnostrict 
    STRICT | NOSTRICT 

Purpose
Turns off aggressive optimizations that have the potential to alter the semantics of your program.

Notes
-qnostrict has no effect at -O optimization level 0.

-qstrict turns off the following optimizations:

• Performing code motion and scheduling on computations such as loads and floating-point computations that may trigger an exception.
• Relaxing conformance to IEEE rules.
• Reassociating floating-point expressions.

Unless explicitly set otherwise by the -qfloat option:

• -qstrict sets -qfloat=nofltint:norsqrt.
• -qnostrict sets -qfloat=fltint:rsqrt.

You can use -qfloat=fltint and -qfloat=rsqrt to override the -qstrict settings.

For example:

• Using -O3 -qstrict -qfloat=fltint means that -qfloat=fltint is in effect, but there are no other aggressive optimizations.
• Using -O3 -qnostrict -qfloat=norsqrt means that the compiler performs all aggressive optimizations except -qfloat=rsqrt.

Defaults
Default setting for the strict option varies according to -O optimization level in effect:

Optimization level	Default setting for strict option
0	-qstrict
2	-qstrict
3	-qnostrict
4	-qnostrict

You can override the default settings by explicitly setting either -qstrict or -qnostrict. In the example below, -qstrict is active regardless of the -O3 optimization level selected.

xlc myprogram.c -O3 -qstrict -qfloat=fltint:rsqrt

Example
To compile myprogram.c so that the aggressive optimizations of -O3 are turned off, range checking is turned off (-qfloat=fltint), and division by the result of a square root is replaced by multiplying by the reciprocal (-qfloat=rsqrt), enter:

xlc myprogram.c -O3 -qstrict -qfloat=fltint:rsqrt

List of Compiler Options and Their Defaults
strict_induction compiler option