update implementation

Author: HarshitaKalani

pydatastructs/linear_data_structures/_backend/cpp/algorithms/llvm_algorithms.py

@@ -151,11 +151,10 @@ def _build_insertion_sort_ir(dtype: str) -> str:
 
     fn_ty = ir.FunctionType(ir.VoidType(), [T.as_pointer(), i32])
     fn = ir.Function(mod, fn_ty, name=fn_name)
-
     arr, n = fn.args
     arr.name, n.name = "arr", "n"
 
-    # Basic blocks
+    # --- Basic blocks ---
     b_entry = fn.append_basic_block("entry")
     b_outer = fn.append_basic_block("outer")
     b_inner_cond = fn.append_basic_block("inner.cond")
@@ -165,27 +164,32 @@ def _build_insertion_sort_ir(dtype: str) -> str:
     b_exit = fn.append_basic_block("exit")
 
     b = ir.IRBuilder(b_entry)
-
     cond_trivial = b.icmp_signed("<=", n, ir.Constant(i32, 1))
     b.cbranch(cond_trivial, b_exit, b_outer)
 
+    # --- Outer loop ---
     b.position_at_end(b_outer)
     i_phi = b.phi(i32, name="i")
-    i_phi.add_incoming(ir.Constant(i32, 1), b_entry)  # start from 1 for insertion sort
+    i_phi.add_incoming(ir.Constant(i32, 1), b_entry)
 
     cond_outer = b.icmp_signed("<", i_phi, n)
     b.cbranch(cond_outer, b_inner_cond, b_exit)
 
+    # --- Inner loop condition ---
     b.position_at_end(b_inner_cond)
+    # PHI first
+    j_phi = b.phi(i32, name="j")
+    j_phi.add_incoming(i_phi, b_outer)
+    # Note: add incoming from inner.latch later after defining b_inner_latch
+
+    # Load key after PHI
     key_ptr = b.gep(arr, [i_phi])
     key_val = b.load(key_ptr, name="key_val")
 
-    j_phi = b.phi(i32, name="j")
-    j_phi.add_incoming(i_phi, b_outer)  # j = i
-
-    inner_cond = b.icmp_signed(">", j_phi, ir.Constant(i32, 0))
-    b.cbranch(inner_cond, b_inner_body, b_outer_latch)
+    cond_inner = b.icmp_signed(">", j_phi, ir.Constant(i32, 0))
+    b.cbranch(cond_inner, b_inner_body, b_outer_latch)
 
+    # --- Inner loop body ---
     b.position_at_end(b_inner_body)
     j_minus_1 = b.sub(j_phi, ir.Constant(i32, 1))
     ptr_j_minus_1 = b.gep(arr, [j_minus_1])
@@ -194,14 +198,16 @@ def _build_insertion_sort_ir(dtype: str) -> str:
     cmp = b.icmp_signed(">", val_j_minus_1, key_val) if isinstance(T, ir.IntType) else b.fcmp_ordered(">", val_j_minus_1, key_val)
     b.cbranch(cmp, b_inner_latch, b_outer_latch)
 
+    # --- Inner loop latch (shift element left) ---
     b.position_at_end(b_inner_latch)
     ptr_j = b.gep(arr, [j_phi])
     b.store(val_j_minus_1, ptr_j)
 
     j_next = b.sub(j_phi, ir.Constant(i32, 1))
-    j_phi.add_incoming(j_next, b_inner_latch)
+    j_phi.add_incoming(j_next, b_inner_latch)  # now PHI incoming from latch
     b.branch(b_inner_cond)
 
+    # --- Outer latch (store key and increment i) ---
     b.position_at_end(b_outer_latch)
     ptr_j = b.gep(arr, [j_phi])
     b.store(key_val, ptr_j)
@@ -210,12 +216,13 @@ def _build_insertion_sort_ir(dtype: str) -> str:
     i_phi.add_incoming(i_next, b_outer_latch)
     b.branch(b_outer)
 
-    # Exit
+    # --- Exit ---
     b.position_at_end(b_exit)
     b.ret_void()
 
     return str(mod)
 
+
 def _materialize(dtype: str, algo: str) -> int:
     _ensure_target_machine()