Common Subexpression Elimination
Common Subexpression Elimination
In compilers Common Subexpression Elimination is an optimization where a compiler searches for instances of identical expressions, and replaces them with a single variable for the computed value.
a = b * c + g;
d = b * c + e;
// can be optimized as
tmp = b * c;
a = tmp + g;
d = tmp + e;
This is present in GCC in optimization levels higher than -O2, can be added manually with -fgcse