mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-12-29 19:18:37 +02:00
1d8d224223
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@18019 3c298f89-4303-0410-b956-a3cf2f4a3e73
73 lines
2.8 KiB
Diff
73 lines
2.8 KiB
Diff
Hi,
|
|
|
|
The attached patch makes sure that we create smaller object code for
|
|
simple switch statements. We just make sure to flatten the switch
|
|
statement into an if-else chain, basically.
|
|
|
|
This fixes a size-regression as compared to gcc-3.4, as can be seen
|
|
below.
|
|
|
|
2007-04-15 Bernhard Fischer <..>
|
|
|
|
* stmt.c (expand_case): Do not create a complex binary tree when
|
|
optimizing for size but rather use the simple ordered list.
|
|
(emit_case_nodes): do not emit jumps to the default_label when
|
|
optimizing for size.
|
|
|
|
Not regtested so far.
|
|
Comments?
|
|
|
|
Attached is the test switch.c mentioned below.
|
|
|
|
$ for i in 2.95 3.3 3.4 4.0 4.1 4.2.orig-HEAD 4.3.orig-HEAD 4.3-HEAD;do
|
|
gcc-$i -DCHAIN -Os -o switch-CHAIN-$i.o -c switch.c ;done
|
|
$ for i in 2.95 3.3 3.4 4.0 4.1 4.2.orig-HEAD 4.3.orig-HEAD 4.3-HEAD;do
|
|
gcc-$i -UCHAIN -Os -o switch-$i.o -c switch.c ;done
|
|
|
|
$ size switch-*.o
|
|
text data bss dec hex filename
|
|
169 0 0 169 a9 switch-2.95.o
|
|
115 0 0 115 73 switch-3.3.o
|
|
103 0 0 103 67 switch-3.4.o
|
|
124 0 0 124 7c switch-4.0.o
|
|
124 0 0 124 7c switch-4.1.o
|
|
124 0 0 124 7c switch-4.2.orig-HEAD.o
|
|
95 0 0 95 5f switch-4.3-HEAD.o
|
|
124 0 0 124 7c switch-4.3.orig-HEAD.o
|
|
166 0 0 166 a6 switch-CHAIN-2.95.o
|
|
111 0 0 111 6f switch-CHAIN-3.3.o
|
|
95 0 0 95 5f switch-CHAIN-3.4.o
|
|
95 0 0 95 5f switch-CHAIN-4.0.o
|
|
95 0 0 95 5f switch-CHAIN-4.1.o
|
|
95 0 0 95 5f switch-CHAIN-4.2.orig-HEAD.o
|
|
95 0 0 95 5f switch-CHAIN-4.3-HEAD.o
|
|
95 0 0 95 5f switch-CHAIN-4.3.orig-HEAD.o
|
|
|
|
|
|
Content-Type: text/x-diff; charset=us-ascii
|
|
Content-Disposition: attachment; filename="gcc-4.3.gcc-flatten-switch-stmt.00.diff"
|
|
|
|
--- a/gcc/stmt.c
|
|
+++ b/gcc/stmt.c
|
|
@@ -2574,7 +2574,11 @@ expand_case (tree exp)
|
|
use_cost_table
|
|
= (TREE_CODE (orig_type) != ENUMERAL_TYPE
|
|
&& estimate_case_costs (case_list));
|
|
- balance_case_nodes (&case_list, NULL);
|
|
+ /* When optimizing for size, we want a straight list to avoid
|
|
+ jumps as much as possible. This basically creates an if-else
|
|
+ chain. */
|
|
+ if (!optimize_size)
|
|
+ balance_case_nodes (&case_list, NULL);
|
|
emit_case_nodes (index, case_list, default_label, index_type);
|
|
emit_jump (default_label);
|
|
}
|
|
@@ -3136,6 +3140,7 @@ emit_case_nodes (rtx index, case_node_pt
|
|
{
|
|
if (!node_has_low_bound (node, index_type))
|
|
{
|
|
+ if (!optimize_size) /* don't jl to the .default_label. */
|
|
emit_cmp_and_jump_insns (index,
|
|
convert_modes
|
|
(mode, imode,
|