- when a graph is lowered because of struct return changes, transform

[libfirm] / ir / lower / lower_switch.c

diff --git a/ir/lower/lower_switch.c b/ir/lower/lower_switch.c
index 301cba4..3570c25 100644 (file)
--- a/ir/lower/lower_switch.c
+++ b/ir/lower/lower_switch.c
@@ -24,12 +24,11 @@
  * @version $Id$
  */
 
-#ifdef HAVE_CONFIG_H
 #include "config.h"
-#endif
 
 #include <limits.h>
 
+#include "array_t.h"
 #include "ircons.h"
 #include "irgopt.h"
 #include "irgwalk.h"
@@ -71,21 +70,21 @@ static int should_do_table_switch(ir_node *cond, unsigned spare_size)
        unsigned long spare, num_cases = 0;
 
        /* TODO: Minimum size for jump table? */
-       if(get_irn_n_outs(cond) <= 4)
+       if (get_irn_n_outs(cond) <= 4)
                return 0;
 
        default_pn = get_Cond_defaultProj(cond);
 
        foreach_out_irn(cond, i, proj) {
                long pn = get_Proj_proj(proj);
-               if(pn == default_pn)
+               if (pn == default_pn)
                        continue;
 
-               if(pn < switch_min)
+               if (pn < switch_min)
                        switch_min = pn;
-               if(pn > switch_max)
+               if (pn > switch_max)
                        switch_max = pn;
-               num_cases++;
+               ++num_cases;
        }
 
        /*
@@ -98,7 +97,9 @@ static int should_do_table_switch(ir_node *cond, unsigned spare_size)
 
 static int casecmp(const void *a, const void *b)
 {
-       return ((case_data_t *) a)->value - ((case_data_t *) b)->value;
+       const case_data_t *cda = a;
+       const case_data_t *cdb = b;
+       return (cda->value > cdb->value) - (cda->value < cdb->value);
 }
 
 /**
@@ -107,10 +108,14 @@ static int casecmp(const void *a, const void *b)
 static void create_if_cascade(ifcas_env_t *env, ir_node *curblock,
                               case_data_t *curcases, int numcases)
 {
+       assert(numcases >= 0);
+
        set_cur_block(curblock);
 
-       if(numcases == 1)
-       {
+       if (numcases == 0) {
+               /* zero cases: "goto default;" */
+               env->defusers[env->defindex++] = new_Jmp();
+       } else if (numcases == 1) {
                /* only one case: "if(sel == val) goto target else goto default;" */
                ir_node *val  = new_Const_long(get_irn_mode(env->sel), curcases[0].value);
                ir_node *cmp  = new_Cmp(env->sel, val);
@@ -118,7 +123,7 @@ static void create_if_cascade(ifcas_env_t *env, ir_node *curblock,
                ir_node *cond = new_Cond(proj);
                set_Block_cfgpred(curcases[0].target, 0, new_Proj(cond, mode_X, pn_Cond_true));
                env->defusers[env->defindex++] = new_Proj(cond, mode_X, pn_Cond_false);
-       } else if(numcases == 2) {
+       } else if (numcases == 2) {
                /* only two cases: "if(sel == val[0]) goto target[0];" */
                ir_node *val  = new_Const_long(get_irn_mode(env->sel), curcases[0].value);
                ir_node *cmp  = new_Cmp(env->sel, val);
@@ -179,31 +184,32 @@ static void find_cond_nodes(ir_node *block, void *ctx)
        ir_node     *defblock = NULL;
        ifcas_env_t  ifcas_env;
 
-       if(get_Block_n_cfgpreds(block) != 1)
+       if (get_Block_n_cfgpreds(block) != 1)
                return;
 
        projx = get_Block_cfgpred(block, 0);
-       if(!is_Proj(projx))
+       if (!is_Proj(projx))
                return;
        assert(get_irn_mode(projx) == mode_X);
 
        cond = get_Proj_pred(projx);
-       if(!is_Cond(cond))
+       if (!is_Cond(cond))
                return;
 
        sel      = get_Cond_selector(cond);
        sel_mode = get_irn_mode(sel);
 
-       if(sel_mode == mode_b)    /* not a switch? */
+       if (sel_mode == mode_b)    /* not a switch? */
                return;
 
-       if(should_do_table_switch(cond, env->spare_size))
+       if (should_do_table_switch(cond, env->spare_size))
                return;
 
        /*
         * Switch should be transformed into an if cascade.
         * So first order the cases, so we can do a binary search on them.
         */
+       env->changed = 1;
 
        numcases = get_irn_n_outs(cond) - 1;      // does not contain default case
        NEW_ARR_A(case_data_t, cases, numcases);
@@ -218,8 +224,7 @@ static void find_cond_nodes(ir_node *block, void *ctx)
                ir_node *target = get_irn_out(proj, 0);
                assert(get_Block_n_cfgpreds(target) == 1 && "Encountered critical edge in switch");
 
-               if(pn == default_pn)
-               {
+               if (pn == default_pn) {
                        defblock = target;
                        continue;
                }
@@ -255,6 +260,7 @@ void lower_switch(ir_graph *irg, unsigned spare_size)
 
        current_ir_graph = irg;
 
+       env.changed    = 0;
        env.spare_size = spare_size;
 
        remove_critical_cf_edges(irg);
@@ -262,13 +268,12 @@ void lower_switch(ir_graph *irg, unsigned spare_size)
 
        irg_block_walk_graph(irg, find_cond_nodes, NULL, &env);
 
-       if(env.changed) {
+       if (env.changed) {
                /* control flow changed */
                set_irg_outs_inconsistent(irg);
                set_irg_doms_inconsistent(irg);
                set_irg_extblk_inconsistent(irg);
                set_irg_loopinfo_inconsistent(irg);
        }
-
        current_ir_graph = rem;
 }