phiprop: Move vuse variable declaration closer to its use.
This commit improves code readability in the phiprop pass by moving the declaration of the `vuse` variable closer to where it is used.
This is a minor code cleanup in the phiprop optimization pass. The declaration of the vuse variable within the propagate_with_phi function has been moved to directly precede its usage. This improves code readability by reducing the distance between the declaration and the use of the variable, making the code easier to understand and maintain.
In Details
This commit modifies tree-ssa-phiprop.cc by moving the declaration of the vuse variable within the propagate_with_phi function. vuse likely represents a use of a virtual operand. This change has no functional impact on the optimization itself but improves the code's structure and readability for developers working on the phiprop pass.
For Context
The SSA (Static Single Assignment) form is an intermediate representation used by compilers. The phi-propagation (phiprop) pass is an optimization that simplifies code by replacing uses of variables defined by phi-nodes with their original values. This commit doesn't change the optimization itself but makes the code implementing the optimization slightly easier to read.