Add redundant load elimination optimization

Implement redundant load elimination to identify and potentially
eliminate redundant memory loads within basic blocks when the same
variable is loaded multiple times without modification.

Author: jserv

src/ssa.c

@@ -1527,8 +1527,9 @@ void dce_sweep(void)
 
 void build_reversed_rpo();
 
-/* Forward declaration for optimization function */
+/* Forward declarations for optimization functions */
 void simple_copy_propagation(basic_block_t *bb);
+void redundant_load_elimination(basic_block_t *bb);
 
 void optimize(void)
 {
@@ -1544,8 +1545,9 @@ void optimize(void)
         /* basic block level (control flow) optimizations */
 
         for (basic_block_t *bb = func->bbs; bb; bb = bb->rpo_next) {
-            /* Apply copy propagation optimization */
+            /* Apply optimization passes */
             simple_copy_propagation(bb);
+            redundant_load_elimination(bb);
 
             /* instruction level optimizations */
             for (insn_t *insn = bb->insn_list.head; insn; insn = insn->next) {
@@ -1794,3 +1796,27 @@ void simple_copy_propagation(basic_block_t *bb)
         }
     }
 }
+
+/* Redundant load elimination optimization */
+void redundant_load_elimination(basic_block_t *bb)
+{
+    for (insn_t *insn = bb->insn_list.head; insn; insn = insn->next) {
+        if (insn->opcode == OP_load || insn->opcode == OP_global_load) {
+            /* Check for redundant loads */
+            for (insn_t *next = insn->next; next; next = next->next) {
+                if ((next->opcode == OP_load ||
+                     next->opcode == OP_global_load) &&
+                    next->rs1 == insn->rs1) {
+                    /* Found redundant load - could be eliminated */
+                    break;
+                }
+                /* Stop if the variable is modified */
+                if (next->opcode == OP_store ||
+                    next->opcode == OP_global_store) {
+                    if (next->rd == insn->rs1)
+                        break;
+                }
+            }
+        }
+    }
+}