Hi!
The following patch fixes a bug in tree-switch-conversion.c with
signed index_expr's. build_arrays would compute index_expr - range_min
in index_expr's type and use that as index into CSWTCH.N array,
which is wrong, because in this case index_expr 98 - (-62) computed
in signed char type results in signed overflow and we end up
loading from CSWTCH.2[-96]. Apparently for the bounds checking
we perform the same index_expr - range_min computation, but in
corresponding unsigned type. This patch computes it just once in
unsigned type, so that overflow isn't undefined.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk/4.6/4.5/4.4?
2011-04-29 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/48809
* tree-switch-conversion.c (build_arrays): Compute tidx in unsigned
type.
(gen_inbound_check): Don't compute index_expr - range_min in utype
again, instead reuse SSA_NAME initialized in build_arrays.
Remove two useless gsi_for_stmt calls.
* gcc.c-torture/execute/pr48809.c: New test.
--- gcc/tree-switch-conversion.c.jj 2010-12-02 11:51:32.000000000 +0100
+++ gcc/tree-switch-conversion.c 2011-04-29 15:23:57.000000000 +0200
@@ -1,6 +1,6 @@
/* Switch Conversion converts variable initializations based on switch
statements to initializations from a static array.
- Copyright (C) 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
+ Copyright (C) 2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
Contributed by Martin Jambor <jamb...@suse.cz>
This file is part of GCC.
@@ -656,7 +656,7 @@ static void
build_arrays (gimple swtch)
{
tree arr_index_type;
- tree tidx, sub, tmp;
+ tree tidx, sub, tmp, utype;
gimple stmt;
gimple_stmt_iterator gsi;
int i;
@@ -664,14 +664,20 @@ build_arrays (gimple swtch)
gsi = gsi_for_stmt (swtch);
+ /* Make sure we do not generate arithmetics in a subrange. */
+ utype = TREE_TYPE (info.index_expr);
+ if (TREE_TYPE (utype))
+ utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1);
+ else
+ utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1);
+
arr_index_type = build_index_type (info.range_size);
- tmp = create_tmp_var (TREE_TYPE (info.index_expr), "csti");
+ tmp = create_tmp_var (utype, "csui");
add_referenced_var (tmp);
tidx = make_ssa_name (tmp, NULL);
- sub = fold_build2_loc (loc, MINUS_EXPR,
- TREE_TYPE (info.index_expr), info.index_expr,
- fold_convert_loc (loc, TREE_TYPE (info.index_expr),
- info.range_min));
+ sub = fold_build2_loc (loc, MINUS_EXPR, utype,
+ fold_convert_loc (loc, utype, info.index_expr),
+ fold_convert_loc (loc, utype, info.range_min));
sub = force_gimple_operand_gsi (&gsi, sub,
false, NULL, true, GSI_SAME_STMT);
stmt = gimple_build_assign (tidx, sub);
@@ -780,12 +786,7 @@ gen_inbound_check (gimple swtch)
tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION);
tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION);
gimple label1, label2, label3;
-
- tree utype;
- tree tmp_u_1, tmp_u_2, tmp_u_var;
- tree cast;
- gimple cast_assign, minus_assign;
- tree ulb, minus;
+ tree utype, tidx;
tree bound;
gimple cond_stmt;
@@ -799,49 +800,24 @@ gen_inbound_check (gimple swtch)
gcc_assert (info.default_values);
bb0 = gimple_bb (swtch);
- /* Make sure we do not generate arithmetics in a subrange. */
- if (TREE_TYPE (TREE_TYPE (info.index_expr)))
- utype = lang_hooks.types.type_for_mode
- (TYPE_MODE (TREE_TYPE (TREE_TYPE (info.index_expr))), 1);
- else
- utype = lang_hooks.types.type_for_mode
- (TYPE_MODE (TREE_TYPE (info.index_expr)), 1);
+ tidx = gimple_assign_lhs (info.arr_ref_first);
+ utype = TREE_TYPE (tidx);
/* (end of) block 0 */
gsi = gsi_for_stmt (info.arr_ref_first);
- tmp_u_var = create_tmp_var (utype, "csui");
- add_referenced_var (tmp_u_var);
- tmp_u_1 = make_ssa_name (tmp_u_var, NULL);
-
- cast = fold_convert_loc (loc, utype, info.index_expr);
- cast_assign = gimple_build_assign (tmp_u_1, cast);
- SSA_NAME_DEF_STMT (tmp_u_1) = cast_assign;
- gsi_insert_before (&gsi, cast_assign, GSI_SAME_STMT);
- update_stmt (cast_assign);
-
- ulb = fold_convert_loc (loc, utype, info.range_min);
- minus = fold_build2_loc (loc, MINUS_EXPR, utype, tmp_u_1, ulb);
- minus = force_gimple_operand_gsi (&gsi, minus, false, NULL, true,
- GSI_SAME_STMT);
- tmp_u_2 = make_ssa_name (tmp_u_var, NULL);
- minus_assign = gimple_build_assign (tmp_u_2, minus);
- SSA_NAME_DEF_STMT (tmp_u_2) = minus_assign;
- gsi_insert_before (&gsi, minus_assign, GSI_SAME_STMT);
- update_stmt (minus_assign);
+ gsi_next (&gsi);
bound = fold_convert_loc (loc, utype, info.range_size);
- cond_stmt = gimple_build_cond (LE_EXPR, tmp_u_2, bound, NULL_TREE,
NULL_TREE);
+ cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE);
gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT);
update_stmt (cond_stmt);
/* block 2 */
- gsi = gsi_for_stmt (info.arr_ref_first);
label2 = gimple_build_label (label_decl2);
gsi_insert_before (&gsi, label2, GSI_SAME_STMT);
last_assign = gen_def_assigns (&gsi);
/* block 1 */
- gsi = gsi_for_stmt (info.arr_ref_first);
label1 = gimple_build_label (label_decl1);
gsi_insert_before (&gsi, label1, GSI_SAME_STMT);
--- gcc/testsuite/gcc.c-torture/execute/pr48809.c.jj 2011-04-29
15:30:29.000000000 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr48809.c 2011-04-29
15:29:49.000000000 +0200
@@ -0,0 +1,60 @@
+/* PR tree-optimization/48809 */
+
+extern void abort (void);
+
+int
+foo (signed char x)
+{
+ int y = 0;
+ switch (x)
+ {
+ case 0: y = 1; break;
+ case 1: y = 7; break;
+ case 2: y = 2; break;
+ case 3: y = 19; break;
+ case 4: y = 5; break;
+ case 5: y = 17; break;
+ case 6: y = 31; break;
+ case 7: y = 8; break;
+ case 8: y = 28; break;
+ case 9: y = 16; break;
+ case 10: y = 31; break;
+ case 11: y = 12; break;
+ case 12: y = 15; break;
+ case 13: y = 111; break;
+ case 14: y = 17; break;
+ case 15: y = 10; break;
+ case 16: y = 31; break;
+ case 17: y = 7; break;
+ case 18: y = 2; break;
+ case 19: y = 19; break;
+ case 20: y = 5; break;
+ case 21: y = 107; break;
+ case 22: y = 31; break;
+ case 23: y = 8; break;
+ case 24: y = 28; break;
+ case 25: y = 106; break;
+ case 26: y = 31; break;
+ case 27: y = 102; break;
+ case 28: y = 105; break;
+ case 29: y = 111; break;
+ case 30: y = 17; break;
+ case 31: y = 10; break;
+ case 32: y = 31; break;
+ case 98: y = 18; break;
+ case -62: y = 19; break;
+ }
+ return y;
+}
+
+int
+main ()
+{
+ if (foo (98) != 18 || foo (97) != 0 || foo (99) != 0)
+ abort ();
+ if (foo (-62) != 19 || foo (-63) != 0 || foo (-61) != 0)
+ abort ();
+ if (foo (28) != 105 || foo (27) != 102 || foo (29) != 111)
+ abort ();
+ return 0;
+}
Jakub
