Memory leak: Phi instructions not released in SSA construction #275
Description
Description
Memory leak detected in the SSA construction phase where phi instructions are not properly released after use, causing unnecessary memory consumption that grows with program complexity.
Current Behavior
- Phi instructions allocated during SSA construction remain in memory after they're no longer needed
- Memory usage increases unnecessarily with program size
Expected Behavior
Phi instructions should be properly freed after SSA construction completes to prevent memory leaks.
Location in Code
- Primary location:
src/ssa.c - Function:
solve_phi_params() - Comment in code: "FIXME: dangling phi causes memory leak. Should release phi here."
Impact
- Memory consumption grows unnecessarily with program complexity
- Can affect compilation of large programs
- Reduces efficiency of the self-hosting compiler
Test Case
// Large program with many control flow paths will show increased memory usage
int complex_function(int n) {
int result = 0;
for (int i = 0; i < n; i++) {
if (i % 2 == 0) {
result += i;
} else {
result -= i;
}
// More complex control flow increases phi nodes
for (int j = 0; j < i; j++) {
if (j % 3 == 0) {
result *= 2;
}
}
}
return result;
}Proposed Solution
Add proper cleanup code to release phi instructions after they're no longer needed in the SSA construction phase.
References
- Related to SSA (Static Single Assignment) form optimization
- Affects memory management in
INSN_ARENA