#include "coretypes.h"
#include "tm.h"
#include "ggc.h"
-
+#include "diagnostic.h"
+#include "toplev.h"
/* These RTL headers are needed for basic-block.h. */
#include "rtl.h"
#include "tm_p.h"
int removed_phis;
} stats;
-static VEC(tree,heap) *worklist;
+
+static VEC (tree, heap) *worklist;
+static VEC (tree, heap) *cond_dead_built_in_calls;
/* Vector indicating an SSA name has already been processed and marked
as necessary. */
#define NECESSARY(stmt) stmt->base.asm_written_flag
+/* Conditional dead call elimination
+
+ Some builtin functions can set errno on error conditions, but they
+ are otherwise pure. If the result of a call to such a function is
+ not used, the compiler can still not eliminate the call without
+ powerful interprocedural analysis to prove that the errno is not
+ checked. However, if the conditions under which the error occurs
+ are known, compiler can conditionally dead code eliminate the calls
+ by shrink-wrapping the semi-dead calls into the error condition:
+
+ built_in_call(args)
+ ==>
+ if (error_cond(args))
+ built_in_call(args)
+
+ ( An actual simple exampl is :
+ log (x); // Mostly dead call
+ ==>
+ if (x < 0)
+ log(x);
+ With this change, call to log(x) is effectively eliminated, as
+ in majority of the cases, log won't be called with x out of
+ range. The branch is totally predicatible, so the branch cost
+ is low. Such optimization improves the performance of
+ an important application in a big search company by 20% )
+
+ Note that library functions are not supposed to clear errno to zero without
+ error.
+
+ In this implementation, only 'pow' and 'log' are handled. ('sin' and 'cos'
+ seem to be wrongly handled by gcc -- they are treated as not touching errno
+ which is not correct.)
+
+ The condition wrapping the builtin call is conservatively set to avoid too
+ aggressive (wrong) shrink wrapping. The optimization is called conditional
+ dead call elimination because the call is eliminated under the condition
+ that the input arguments would not lead to domain or range error (for
+ instance when x <= 0 for a log(x) call), however the chances that the error
+ condition is hit is very low (those builtin calls which are conditionally
+ dead are usually part of the C++ abstraction penalty exposed after
+ inlining). */
+
+
+static bool
+check_pow (tree pow_call)
+{
+ tree base, expn;
+ enum tree_code bc, ec;
+
+ gcc_assert (TREE_CODE (pow_call) == CALL_EXPR);
+ if (call_expr_nargs (pow_call) != 2)
+ return false;
+
+ base = CALL_EXPR_ARG (pow_call, 0);
+ expn = CALL_EXPR_ARG (pow_call, 1);
+
+ bc = TREE_CODE (base);
+ ec = TREE_CODE (expn);
+
+ gcc_assert (TREE_CODE_CLASS (bc) != tcc_constant
+ || bc == REAL_CST);
+ gcc_assert (TREE_CODE_CLASS (ec) != tcc_constant
+ || ec == REAL_CST);
+
+ /* Folding candidates are not interesting. */
+ if (ec == REAL_CST && bc == REAL_CST)
+ return false;
+
+ if (bc == REAL_CST)
+ {
+ /* Only handle a fixed range of constant. */
+ REAL_VALUE_TYPE mv;
+ REAL_VALUE_TYPE bcv = TREE_REAL_CST (base);
+ if (REAL_VALUES_EQUAL (bcv, dconst1))
+ return false;
+ if (REAL_VALUES_LESS (bcv, dconst1))
+ return false;
+ real_from_integer (&mv, VOIDmode,256,0,1);
+ if (REAL_VALUES_LESS (mv, bcv))
+ return false;
+ return true;
+ }
+ else if (bc == SSA_NAME)
+ {
+ tree def, nm, rhs, rhs0, var, typ;
+ int sz;
+
+ def = SSA_NAME_DEF_STMT (base);
+ if (TREE_CODE (def) != GIMPLE_MODIFY_STMT)
+ return false;
+
+ nm = GIMPLE_STMT_OPERAND (def,0);
+ gcc_assert (TREE_CODE (nm) == SSA_NAME);
+ if (nm != base)
+ return false;
+
+ rhs = GIMPLE_STMT_OPERAND (def,1);
+
+ if (TREE_CODE (rhs) != FLOAT_EXPR)
+ return false;
+ rhs0 = TREE_OPERAND (rhs,0);
+
+ if (TREE_CODE (rhs0) != SSA_NAME)
+ return false;
+
+ var = SSA_NAME_VAR (rhs0);
+ if (TREE_CODE (var) != VAR_DECL &&
+ TREE_CODE (var) != PARM_DECL)
+ return false;
+
+ typ = TREE_TYPE (var);
+ if (TREE_CODE (typ) != INTEGER_TYPE)
+ return false;
+ sz = int_size_in_bytes (typ);
+ if (sz == -1 || sz > INT_TYPE_SIZE)
+ return false;
+
+ return true;
+ }
+ else
+ return false;
+}
+
+static bool
+check_log (tree log_call)
+{
+ tree arg_typ;
+ gcc_assert (TREE_CODE (log_call) == CALL_EXPR);
+ if (call_expr_nargs (log_call) != 1)
+ return false;
+
+ arg_typ = TREE_TYPE (CALL_EXPR_ARG (log_call, 0));
+ if (!is_gimple_reg_type (arg_typ))
+ return false;
+ return true;
+}
+
+
+/* A helper function to determine if a builtin function
+ call is a candidate for conditional DCE. */
+
+static bool
+is_unnecessary_except_errno_call (tree call)
+{
+ tree fn;
+ bool is_unnecessary_except_errno = false;
+ enum built_in_function fnc;
+
+ if (!flag_tree_builtin_dce)
+ return false;
+
+ gcc_assert (call);
+ gcc_assert (!DECL_P (call));
+ gcc_assert (TREE_CODE (call) == CALL_EXPR);
+
+ fn = get_callee_fndecl (call);
+ if (!fn || !DECL_BUILT_IN (fn))
+ return false;
+
+ fnc = DECL_FUNCTION_CODE (fn);
+ switch (fnc)
+ {
+ CASE_FLT_FN (BUILT_IN_POW):
+ if (check_pow (call))
+ is_unnecessary_except_errno = true;
+ break;
+
+ CASE_FLT_FN (BUILT_IN_LOG):
+ if (check_log (call))
+ is_unnecessary_except_errno = true;
+ break;
+ default :
+ is_unnecessary_except_errno = false;
+ break;
+ }
+
+ if (!is_unnecessary_except_errno)
+ return false;
+
+ return is_unnecessary_except_errno;
+}
+
+
/* If STMT is not already marked necessary, mark it, and add it to the
worklist if ADD_TO_WORKLIST is true. */
static inline void
if (NECESSARY (stmt) || IS_EMPTY_STMT (stmt))
return;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, " Marked as necessary: ");
+ print_generic_stmt (dump_file, stmt, TDF_SLIM);
+ fprintf (dump_file, "\n");
+ }
+
NECESSARY (stmt) = 1;
VEC_safe_push (tree, heap, worklist, stmt);
}
/* Most, but not all function calls are required. Function calls that
produce no result and have no side effects (i.e. const pure
functions) are unnecessary. */
- if (TREE_SIDE_EFFECTS (stmt))
- mark_stmt_necessary (stmt, true);
+ if (TREE_SIDE_EFFECTS (stmt))
+ mark_stmt_necessary (stmt, true);
+
return;
case GIMPLE_MODIFY_STMT:
op = get_call_expr_in (stmt);
if (op && TREE_SIDE_EFFECTS (op))
{
- mark_stmt_necessary (stmt, true);
+ mark_stmt_necessary (stmt, true);
return;
}
}
}
+/* Method to generate conditional statements for guarding condionally
+ dead calls to pow. One or more statements can be generated for
+ each logical condition. Statement groups of different conditions
+ are separated by a NULL tree. */
+static void
+gen_conditions_for_pow (tree pow_call, enum built_in_function fnc,
+ VEC (tree, heap)* conds, unsigned * nconds)
+{
+ tree base, expn;
+ enum tree_code bc, ec;
+ gcc_assert (TREE_CODE (pow_call) == CALL_EXPR);
+ gcc_assert (call_expr_nargs (pow_call) == 2);
+ gcc_assert (fnc == BUILT_IN_POW);
+
+ *nconds = 0;
+
+ base = CALL_EXPR_ARG (pow_call, 0);
+ expn = CALL_EXPR_ARG (pow_call, 1);
+
+ bc = TREE_CODE (base);
+ ec = TREE_CODE (expn);
+
+ gcc_assert (TREE_CODE_CLASS (bc) != tcc_constant ||
+ bc == REAL_CST);
+ gcc_assert (TREE_CODE_CLASS (ec) != tcc_constant ||
+ ec == REAL_CST);
+
+ if (bc == REAL_CST)
+ {
+ tree float_typ, max_exp_real_cst;
+ tree temp, tempn, tempc, tempcn, stmt1, stmt2, stmt3;
+ REAL_VALUE_TYPE mv;
+
+ /* See candidate selection in check_pow.
+ Since the candidates have a given range
+ of base values, the guard code generated
+ for such calls: pow(const,y) are simple:
+ if ( y > max_y )
+ pow(const, y);
+ max_y can be computed separately for each
+ const base, but in this implemetation, we
+ choose to compute it using the max base
+ in the allowed range. */
+
+ REAL_VALUE_TYPE bcv = TREE_REAL_CST (base);
+ gcc_assert (!REAL_VALUES_EQUAL (bcv, dconst1));
+ gcc_assert (!REAL_VALUES_LESS (bcv, dconst1));
+ real_from_integer (&mv, VOIDmode,256,0,1),
+ gcc_assert (!REAL_VALUES_LESS (mv, bcv));
+ float_typ = TREE_TYPE (expn);
+
+ max_exp_real_cst = build_real (float_typ, mv);
+ temp = create_tmp_var (float_typ, "DCE_COND");
+ stmt1 = build_gimple_modify_stmt (temp, expn);
+ tempn = make_ssa_name (temp, stmt1);
+ GIMPLE_STMT_OPERAND (stmt1, 0) = tempn;
+
+ tempc = create_tmp_var (boolean_type_node, "DCE_COND_TEST");
+ stmt2 = build_gimple_modify_stmt (tempc,
+ build2 (GT_EXPR,
+ boolean_type_node,
+ tempn, max_exp_real_cst));
+ tempcn = make_ssa_name (tempc, stmt2);
+ GIMPLE_STMT_OPERAND (stmt2, 0) = tempcn;
+
+ stmt3 = build3 (COND_EXPR, void_type_node,
+ tempcn, NULL_TREE, NULL_TREE);
+ VEC_safe_push (tree, heap, conds, stmt1);
+ VEC_safe_push (tree, heap, conds, stmt2);
+ VEC_safe_push (tree, heap, conds, stmt3);
+ (*nconds)++;
+
+ }
+ else if (bc == SSA_NAME)
+ {
+ tree def, nm, rhs, rhs0, var, int_typ, float_typ;
+ tree max_exp_cst, max_exp_real_cst;
+ tree temp1, temp1n, temp2, temp2n, temp2c, temp2cn;
+ tree cst0, stmt1, stmt2, stmt3;
+ int sz, max_exp;
+
+ /* Generate error condition code for pow calls with
+ non constant base value. The candidates selected
+ have their base argument value converted from
+ integer (see check_pow) value (1,2,4 bytes), and
+ the max exp value is computed based on the size
+ of the integer type. The code below first does
+ sanity check and then does code generation. */
+
+ def = SSA_NAME_DEF_STMT (base);
+ gcc_assert (TREE_CODE (def) == GIMPLE_MODIFY_STMT);
+
+ nm = GIMPLE_STMT_OPERAND (def,0);
+ gcc_assert (TREE_CODE (nm) == SSA_NAME);
+ gcc_assert (nm == base);
+
+ rhs = GIMPLE_STMT_OPERAND (def,1);
+
+ gcc_assert (TREE_CODE (rhs) == FLOAT_EXPR);
+ rhs0 = TREE_OPERAND (rhs,0);
+ gcc_assert (TREE_CODE (rhs0) == SSA_NAME);
+
+ var = SSA_NAME_VAR (rhs0);
+ gcc_assert (TREE_CODE (var) == VAR_DECL
+ || TREE_CODE (var) == PARM_DECL);
+
+ int_typ = TREE_TYPE (var);
+ gcc_assert (TREE_CODE (int_typ) == INTEGER_TYPE);
+
+ sz = int_size_in_bytes (int_typ);
+ gcc_assert (sz > 0 && sz <= INT_TYPE_SIZE) ;
+
+
+ float_typ = TREE_TYPE (SSA_NAME_VAR (expn));
+ if (sz == 1)
+ max_exp = 128;
+ else if (sz == 2)
+ max_exp = 64;
+ else
+ {
+ gcc_assert (sz == 4);
+ max_exp = 32;
+ }
+ max_exp_cst = build_int_cst (integer_type_node, max_exp);
+ max_exp_real_cst = build_real_from_int_cst (float_typ, max_exp_cst);
+
+ /* For pow ((dobule)x,y), generate the following conditions:
+ cond 1:
+ temp1 = x;
+ if (temp1 <= 0)
+
+ cond 2:
+ temp2 = y;
+ if (temp2 > max_exp_real_cst) */
+
+ temp2 = create_tmp_var (float_typ, "DCE_COND2");
+ stmt1 = build_gimple_modify_stmt (temp2, expn);
+ temp2n = make_ssa_name (temp2, stmt1);
+ GIMPLE_STMT_OPERAND (stmt1,0) = temp2n;
+
+ temp2c = create_tmp_var (boolean_type_node, "DCE_COND2_TEST");
+ stmt2 = build_gimple_modify_stmt (temp2c,
+ build2 (GT_EXPR,
+ boolean_type_node,
+ temp2n, max_exp_real_cst));
+ temp2cn = make_ssa_name (temp2c, stmt2);
+ GIMPLE_STMT_OPERAND (stmt2, 0) = temp2cn;
+
+ stmt3 = build3 (COND_EXPR, void_type_node,
+ temp2cn, NULL_TREE, NULL_TREE);
+ VEC_safe_push (tree, heap, conds, stmt1);
+ VEC_safe_push (tree, heap, conds, stmt2);
+ VEC_safe_push (tree, heap, conds, stmt3);
+ (*nconds)++;
+
+ /* now a seperator*/
+ VEC_safe_push (tree, heap, conds, NULL);
+
+ temp1 = create_tmp_var (int_typ, "DCE_COND1");
+ cst0 = build_int_cst (int_typ, 0);
+ stmt1 = build_gimple_modify_stmt (temp1, rhs0);
+ temp1n = make_ssa_name (temp1, stmt1);
+ GIMPLE_STMT_OPERAND (stmt1,0) = temp1n;
+ stmt2 = build3 (COND_EXPR, void_type_node,
+ build2 (LE_EXPR, boolean_type_node, temp1n, cst0),
+ NULL_TREE, NULL_TREE);
+
+ VEC_safe_push (tree, heap, conds, stmt1);
+ VEC_safe_push (tree, heap, conds, stmt2);
+ (*nconds)++;
+
+ }
+ else
+ gcc_unreachable ();
+}
+
+/* The method to generate error condition guard code for log(x)
+ calls. */
+static void
+gen_conditions_for_log (tree call, enum built_in_function fnc,
+ VEC (tree, heap)* conds, unsigned * nconds)
+{
+ tree arg, cst0, temp, tempn, tempc, tempcn, stmt1, stmt2, stmt3;
+ gcc_assert (TREE_CODE (call) == CALL_EXPR);
+ gcc_assert (fnc == BUILT_IN_LOG || fnc == BUILT_IN_LOGF || fnc == BUILT_IN_LOGL);
+
+ *nconds = 0;
+
+ /* for log(x),
+ Generate condition
+
+ temp = x
+ if (x <= 0)
+ */
+ arg = CALL_EXPR_ARG (call, 0);
+ cst0 = build_real (TREE_TYPE (arg), dconst0);
+ temp = create_tmp_var (TREE_TYPE (arg), "DCE_COND");
+ stmt1 = build_gimple_modify_stmt (temp, arg);
+ tempn = make_ssa_name (temp, stmt1);
+ GIMPLE_STMT_OPERAND (stmt1,0) = tempn;
+
+ tempc = create_tmp_var (boolean_type_node, "DCE_COND_TEST");
+ stmt2 = build_gimple_modify_stmt (tempc,
+ build2 (LE_EXPR,
+ boolean_type_node,
+ tempn, cst0));
+ tempcn = make_ssa_name (tempc, stmt2);
+ GIMPLE_STMT_OPERAND (stmt2, 0) = tempcn;
+
+ stmt3 = build3 (COND_EXPR, void_type_node, tempcn,
+ NULL_TREE, NULL_TREE);
+
+ VEC_safe_push (tree, heap, conds, stmt1);
+ VEC_safe_push (tree, heap, conds, stmt2);
+ VEC_safe_push (tree, heap, conds, stmt3);
+ (*nconds)++;
+
+}
+
+
+/* The method to generate shrink wrap conditions for partially
+ a dead builtin call whose return value is not used anywhere,
+ but has to be kept live due to potential error condition.
+
+ BI_CALL: the builtin call
+ CONDS : the vector of statements for condition code
+ NCODES : the pointer to the number of logical conditions,
+ which may be different from the length of CONDS
+ vector. Statements belonging to different logical
+ condition are separated by NULL tree in the vector
+*/
+
+static void
+gen_shrink_wrap_conditions (tree bi_call, VEC (tree, heap)* conds, unsigned int * nconds)
+{
+ tree call, fn;
+ enum built_in_function fnc;
+ gcc_assert (nconds && conds);
+ gcc_assert (VEC_length(tree, conds) == 0);
+ gcc_assert (TREE_CODE (bi_call) == GIMPLE_MODIFY_STMT ||
+ TREE_CODE (bi_call) == CALL_EXPR);
+
+ call = bi_call;
+ if (TREE_CODE (call) == GIMPLE_MODIFY_STMT)
+ call = get_call_expr_in (bi_call);
+
+ fn = get_callee_fndecl (call);
+ gcc_assert (fn && DECL_BUILT_IN (fn));
+ fnc = DECL_FUNCTION_CODE (fn);
+ *nconds = 0;
+
+ switch (fnc)
+ {
+ /*CASE_FLT_FN(BUILT_IN_POW)*/
+ case BUILT_IN_POW:
+ gen_conditions_for_pow (call, fnc, conds, nconds);
+ break;
+ /*CASE_FLT_FN(BUILT_IN_LOG):*/
+ case BUILT_IN_LOG:
+ case BUILT_IN_LOGF:
+ case BUILT_IN_LOGL:
+ gen_conditions_for_log (call, fnc, conds, nconds);
+ break;
+ default :
+ gcc_assert (0);
+ break;
+ }
+
+ gcc_assert (*nconds);
+ return;
+}
+
+
+#define ERR_PROB 0.01
+
+/* The method to shrink wrap a partially dead builtin call
+ whose return value is not used anywhere, but has to be kept
+ live due to potential error condition. */
+static void
+shrink_wrap_one_built_in_call (tree bi_call)
+{
+ block_stmt_iterator bi_call_bsi, join_tgt_bsi;
+ basic_block bi_call_bb, join_tgt_bb, guard_bb, guard_bb0;
+ edge join_tgt_in_edge_from_call, join_tgt_in_edge_fall_thru;
+ tree join_tgt_label_decl, join_tgt_label;
+ edge bi_call_in_edge0, guard_bb_in_edge;
+ VEC (tree, heap) *conds;
+ unsigned tn_cond_stmts, nconds;
+ unsigned ci;
+ tree cond_expr = NULL;
+ tree cond_expr_start;
+ tree bi_call_label_decl;
+ tree bi_call_label;
+
+ conds = VEC_alloc (tree, heap, 10);
+ gen_shrink_wrap_conditions (bi_call, conds, &nconds);
+
+ gcc_assert (nconds > 0);
+ /* Make sure no reallocation happens. */
+ gcc_assert (VEC_length (tree, conds) <= 10);
+ gcc_assert (VEC_length (tree, conds) >= nconds);
+ bi_call_bb = bb_for_stmt (bi_call);
+
+ /* Now find the join target bb -- split
+ bi_call_bb if needed */
+ bi_call_bsi = bsi_for_stmt (bi_call);
+
+ gcc_assert (!bsi_end_p (bi_call_bsi));
+ join_tgt_in_edge_from_call = split_block (bi_call_bb, bi_call);
+ bi_call_bsi = bsi_for_stmt (bi_call);
+
+ join_tgt_bb = join_tgt_in_edge_from_call->dest;
+ join_tgt_label_decl = create_artificial_label ();
+ join_tgt_label = build1 (LABEL_EXPR, void_type_node, join_tgt_label_decl);
+ join_tgt_bsi = bsi_start (join_tgt_bb);
+ bsi_insert_before (&join_tgt_bsi, join_tgt_label, BSI_SAME_STMT);
+
+ /* Now it is time to insert the first condtional expression
+ into bi_call_bb and split this bb so that bi_call is
+ shrink-wrapped*/
+ tn_cond_stmts = VEC_length (tree, conds);
+ cond_expr = NULL;
+ cond_expr_start = VEC_index (tree, conds,0);
+ for (ci = 0; ci < tn_cond_stmts; ci++)
+ {
+ tree c = VEC_index (tree, conds, ci);
+ gcc_assert ( c || ci != 0 );
+ if (!c) break;
+ bsi_insert_before (&bi_call_bsi, c, BSI_SAME_STMT);
+ cond_expr = c;
+ }
+ nconds --;
+ ci ++;
+ gcc_assert (cond_expr && TREE_CODE (cond_expr) == COND_EXPR);
+
+ /* now the label*/
+ bi_call_label_decl = create_artificial_label ();
+ bi_call_label = build1 (LABEL_EXPR, void_type_node, bi_call_label_decl);
+ bsi_insert_before (&bi_call_bsi, bi_call_label, BSI_SAME_STMT);
+
+ bi_call_in_edge0 = split_block (bi_call_bb, cond_expr);
+ bi_call_in_edge0->flags &= ~EDGE_FALLTHRU;
+ bi_call_in_edge0->flags |= EDGE_TRUE_VALUE;
+ guard_bb0 = bi_call_bb;
+ bi_call_bb = bi_call_in_edge0->dest;
+ join_tgt_in_edge_fall_thru = make_edge (guard_bb0, join_tgt_bb, EDGE_FALSE_VALUE);
+
+ bi_call_in_edge0->probability = REG_BR_PROB_BASE*ERR_PROB;
+ join_tgt_in_edge_fall_thru->probability =
+ REG_BR_PROB_BASE - bi_call_in_edge0->probability;
+
+ /* code generation for the rest of the conditions */
+ guard_bb = guard_bb0;
+ for (; nconds > 0; )
+ {
+ unsigned ci0;
+ edge bi_call_in_edge;
+ block_stmt_iterator guard_bsi = bsi_for_stmt (cond_expr_start);
+ ci0 = ci;
+ cond_expr_start = VEC_index (tree, conds, ci0);
+ for (; ci < tn_cond_stmts; ci++)
+ {
+ tree c = VEC_index (tree, conds, ci);
+ gcc_assert ( c || ci != ci0 );
+ if (!c)
+ break;
+ bsi_insert_before (&guard_bsi, c, BSI_SAME_STMT);
+ cond_expr = c;
+ }
+ nconds --;
+ ci ++;
+ gcc_assert (cond_expr && TREE_CODE (cond_expr) == COND_EXPR);
+ guard_bb_in_edge = split_block (guard_bb, cond_expr);
+ guard_bb_in_edge->flags &= ~EDGE_FALLTHRU;
+ guard_bb_in_edge->flags |= EDGE_FALSE_VALUE;
+
+ bi_call_in_edge = make_edge (guard_bb, bi_call_bb, EDGE_TRUE_VALUE);
+
+ bi_call_in_edge->probability = REG_BR_PROB_BASE*ERR_PROB;
+ guard_bb_in_edge->probability =
+ REG_BR_PROB_BASE - bi_call_in_edge->probability;
+
+ }
+
+ VEC_free (tree, heap, conds);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ location_t loc;
+ loc = EXPR_LOCATION (bi_call);
+ inform (
+ "%Hfunction call is shrink-wrapped into error conditions.",
+ &loc);
+ }
+}
+
+/* The top level method for conditional dead code shrink
+ wrapping transformation. */
+
+static bool
+shrink_wrap_conditional_dead_built_in_calls (void)
+{
+ unsigned i = 0;
+ unsigned n = VEC_length (tree, cond_dead_built_in_calls);
+ if (n == 0) return false;
+
+ for (; i < n ; i++)
+ {
+ tree bi_call = VEC_index (tree, cond_dead_built_in_calls, i);
+ shrink_wrap_one_built_in_call (bi_call);
+ }
+
+ cfg_altered = true;
+
+ return true;
+}
/* Remove dead PHI nodes from block BB. */
print_generic_stmt (dump_file, t, TDF_SLIM);
fprintf (dump_file, "\n");
}
+
+ if (is_unnecessary_except_errno_call (call))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Found conditional dead call: ");
+ print_generic_stmt (dump_file, t, TDF_SLIM);
+ fprintf (dump_file, "\n");
+ }
+ VEC_safe_push (tree, heap, cond_dead_built_in_calls, call);
+ }
+
push_stmt_changes (bsi_stmt_ptr (i));
TREE_BLOCK (call) = TREE_BLOCK (t);
bsi_replace (&i, call, false);
mark_symbols_for_renaming (call);
pop_stmt_changes (bsi_stmt_ptr (i));
release_ssa_name (oldlhs);
+
+
}
notice_special_calls (call);
}
}
}
+ something_changed |=
+ shrink_wrap_conditional_dead_built_in_calls ();
+
return something_changed;
}
sbitmap_zero (processed);
worklist = VEC_alloc (tree, heap, 64);
+ cond_dead_built_in_calls = VEC_alloc (tree, heap,64);
cfg_altered = false;
+
}
/* Cleanup after this pass. */
sbitmap_free (processed);
VEC_free (tree, heap, worklist);
+ VEC_free (tree, heap, cond_dead_built_in_calls);
}
+
\f
/* Main routine to eliminate dead code.
find_obviously_necessary_stmts (el);
propagate_necessity (el);
-
+
something_changed |= eliminate_unnecessary_stmts ();
something_changed |= cfg_altered;
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