fixed Jump Tables

ir/be/ia32/ia32_emitter.c

@@ -921,19 +921,9 @@ static void emit_ia32_SwitchJmp(const ir_node *irn, ia32_emit_env_t *emit_env) {
 	interval = tbl.max_value - tbl.min_value;
 
 	/* emit the table */
-	if (tbl.min_value != 0) {
-		lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "sub [%1S-%d], %u", irn, tbl.min_value * 4, interval);
-		lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmp DWORD PTR [%1S-%d], %u", irn, tbl.min_value * 4, interval);
-		snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* first switch value is not 0 */");
-
-		IA32_DO_EMIT(irn);
-	}
-	else {
 	lc_esnprintf(env, cmd_buf, SNPRINTF_BUF_LEN, "cmp %1S, %u", irn, interval);
 	snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* compare for switch */");
-
 	IA32_DO_EMIT(irn);
-	}
 
 	snprintf(cmd_buf, SNPRINTF_BUF_LEN, "ja %s", get_cfop_target(tbl.defProj, buf));
 	snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* default jump if out of range  */");
@@ -952,7 +942,7 @@ static void emit_ia32_SwitchJmp(const ir_node *irn, ia32_emit_env_t *emit_env) {
 		fprintf(F, "%s:\n", tbl.label);
 
 		snprintf(cmd_buf, SNPRINTF_BUF_LEN, ".long %s", get_cfop_target(tbl.branches[0].target, buf));
-		snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */\n",  tbl.branches[0].value);
+		snprintf(cmnt_buf, SNPRINTF_BUF_LEN, "/* case %d */",  tbl.branches[0].value);
 		IA32_DO_EMIT(irn);
 
 		last_value = tbl.branches[0].value;
@@ -967,7 +957,7 @@ static void emit_ia32_SwitchJmp(const ir_node *irn, ia32_emit_env_t *emit_env) {
 			IA32_DO_EMIT(irn);
 		}
 
-		fprintf(F, "\t.text");
+		fprintf(F, "\n\t.text\n\n");
 	}
 	else {
 		/* one jump is enough */

ir/be/ia32/ia32_transform.c

@@ -9,6 +9,8 @@
 #include "config.h"
 #endif
 
+#include <limits.h>
+
 #include "irargs_t.h"
 #include "irnode_t.h"
 #include "irgraph_t.h"
@@ -1475,7 +1477,28 @@ static ir_node *gen_Cond(ia32_transform_env_t *env) {
 		set_ia32_am_support(res, ia32_am_Source);
 	}
 	else {
-		res = new_rd_ia32_SwitchJmp(dbg, irg, block, sel, mode_T);
+		/* determine the smallest switch case value */
+		int switch_min = INT_MAX;
+		const ir_edge_t *edge;
+		char buf[64];
+
+		foreach_out_edge(node, edge) {
+			int pn = get_Proj_proj(get_edge_src_irn(edge));
+			switch_min = pn < switch_min ? pn : switch_min;
+		}
+
+		if (switch_min) {
+			/* if smallest switch case is not 0 we need an additional sub */
+			snprintf(buf, sizeof(buf), "%d", switch_min);
+			res = new_rd_ia32_Lea(dbg, irg, block, sel, noreg, mode_Is);
+			SET_IA32_ORIG_NODE(res, ia32_get_old_node_name(env->cg, env->irn));
+			sub_ia32_am_offs(res, buf);
+			set_ia32_am_flavour(res, ia32_am_OB);
+			set_ia32_am_support(res, ia32_am_Source);
+			set_ia32_op_type(res, ia32_AddrModeS);
+		}
+
+		res = new_rd_ia32_SwitchJmp(dbg, irg, block, switch_min ? res : sel, mode_T);
 		set_ia32_pncode(res, get_Cond_defaultProj(node));
 		set_ia32_res_mode(res, get_irn_mode(sel));
 	}