Implement single-pass live range calculation

Instead of interleaving creation of live-ranges with the main
compiler code, compute them in a separate pass over the opcodes
as part of pass_two. Additionally, do not keep live ranges
synchronized during optimization in opcache and instead use the
same mechanism to recompute them after optimization.

1 files changed, 0 insertions, 77 deletions

diff --git a/ext/opcache/Optimizer/dce.c b/ext/opcache/Optimizer/dce.c
index 95755d559f..a633e9ddf6 100644
--- a/ext/opcache/Optimizer/dce.c
+++ b/ext/opcache/Optimizer/dce.c
@@ -478,79 +478,6 @@ static inline zend_bool may_break_varargs(const zend_op_array *op_array, const z
 	return 0;
 }
 
-static void dce_live_ranges(context *ctx, zend_op_array *op_array, zend_ssa *ssa)
-{
-	int i = 0;
-	int j = 0;
-	zend_live_range *live_range = op_array->live_range;
-
-	while (i < op_array->last_live_range) {
-		if ((live_range->var & ZEND_LIVE_MASK) != ZEND_LIVE_TMPVAR) {
-			/* keep */
-			j++;
-		} else {
-			uint32_t var = live_range->var & ~ZEND_LIVE_MASK;
-			uint32_t def = live_range->start - 1;
-
-			if ((op_array->opcodes[def].result_type == IS_UNUSED) &&
-					(UNEXPECTED(op_array->opcodes[def].opcode == ZEND_EXT_STMT) ||
-					UNEXPECTED(op_array->opcodes[def].opcode == ZEND_EXT_FCALL_END))) {
-				def--;
-			}
-
-			if (op_array->opcodes[def].result_type == IS_UNUSED) {
-				if (op_array->opcodes[def].opcode == ZEND_DO_FCALL) {
-					/* constructor call */
-					do {
-						def--;
-						if ((op_array->opcodes[def].result_type & (IS_TMP_VAR|IS_VAR))
-								&& op_array->opcodes[def].result.var == var) {
-							ZEND_ASSERT(op_array->opcodes[def].opcode == ZEND_NEW);
-							break;
-						}
-					} while (def > 0);
-				} else if (op_array->opcodes[def].opcode == ZEND_OP_DATA) {
-					def--;
-				}
-			}
-
-#if ZEND_DEBUG
-			ZEND_ASSERT(op_array->opcodes[def].result_type & (IS_TMP_VAR|IS_VAR));
-			ZEND_ASSERT(op_array->opcodes[def].result.var == var);
-			ZEND_ASSERT(ssa->ops[def].result_def >= 0);
-#else
-			if (!(op_array->opcodes[def].result_type & (IS_TMP_VAR|IS_VAR))
-					|| op_array->opcodes[def].result.var != var
-					|| ssa->ops[def].result_def < 0) {
-				/* TODO: Some wrong live-range? keep it. */
-				j++;
-				live_range++;
-				i++;
-				continue;
-			}
-#endif
-
-			var = ssa->ops[def].result_def;
-
-			if ((ssa->var_info[var].type & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))
-					&& !is_var_dead(ctx, var)) {
-				/* keep */
-				j++;
-			} else if (i != j) {
-				op_array->live_range[j] = *live_range;
-			}
-		}
-
-		live_range++;
-		i++;
-	}
-	op_array->last_live_range = j;
-	if (op_array->last_live_range == 0) {
-		efree(op_array->live_range);
-		op_array->live_range = NULL;
-	}
-}
-
 int dce_optimize_op_array(zend_op_array *op_array, zend_ssa *ssa, zend_bool reorder_dtor_effects) {
 	int i;
 	zend_ssa_phi *phi;
@@ -648,10 +575,6 @@ int dce_optimize_op_array(zend_op_array *op_array, zend_ssa *ssa, zend_bool reor
 		}
 	}
 
-	if (op_array->live_range) {
-		dce_live_ranges(&ctx, op_array, ssa);
-	}
-
 	/* Eliminate dead instructions */
 	ZEND_BITSET_FOREACH(ctx.instr_dead, ctx.instr_worklist_len, i) {
 		removed_ops += dce_instr(&ctx, &op_array->opcodes[i], &ssa->ops[i]);