AN3350 datasheet(171/185 Pages) STMICROELECTRONICS

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AN3350

Pragmas for optimization

Doc ID 018512 Rev 2

171/185

Remarks

If you enable this pragma, the compiler removes assignments to unused variables before

reassigning them.

This pragma does not correspond to any panel setting. By default, this settings is related to

the global_optimizer level.

22.4

opt_dead_code

Controls the use of dead code optimization.

Syntax

#pragma opt_dead_code on | off | reset

Remarks

If you enable this pragma, the compiler removes a statement that other statements never

execute or call.

This pragma does not correspond to any panel setting. By default, this settings is related to

the global_optimizer level.

22.5

opt_lifetimes

Controls the use of lifetime analysis optimization.

Syntax

#pragma opt_lifetimes on | off | reset

Remarks

If you enable this pragma, the compiler uses the same processor register for different

variables that exist in the same routine but not in the same statement.

This pragma does not correspond to any panel setting. By default, this settings is related to

the global_optimizer level.

22.6

opt_loop_invariants

Controls the use of loop invariant optimization.

Syntax

#pragma opt_loop_invariants on | off | reset

Remarks

If you enable this pragma, the compiler moves all computations that do not change inside a

loop outside the loop, which then runs faster.

This pragma does not correspond to any panel setting.

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