You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
169 lines
4.7 KiB
169 lines
4.7 KiB
# --- SDE-COPYRIGHT-NOTE-BEGIN --- |
|
# This copyright note is auto-generated by ./scripts/Create-CopyPatch. |
|
# |
|
# Filename: package/.../uclibc/pkg_patch/gcc/904-flatten-switch-stmt-00.patch |
|
# Copyright (C) 2009 The OpenSDE Project |
|
# |
|
# More information can be found in the files COPYING and README. |
|
# |
|
# This patch file is dual-licensed. It is available under the license the |
|
# patched project is licensed under, as long as it is an OpenSource license |
|
# as defined at http://www.opensource.org/ (e.g. BSD, X11) or under the terms |
|
# of the GNU General Public License as published by the Free Software |
|
# Foundation; either version 2 of the License, or (at your option) any later |
|
# version. |
|
# --- SDE-COPYRIGHT-NOTE-END --- |
|
|
|
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" |
|
|
|
Index: gcc-4.2.0/gcc/stmt.c |
|
=================================================================== |
|
--- gcc-4.2.0.orig/gcc/stmt.c (revision 123843) |
|
+++ gcc-4.2.0/gcc/stmt.c (working copy) |
|
@@ -2517,7 +2517,11 @@ 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); |
|
} |
|
@@ -3075,6 +3079,7 @@ 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, |
|
|
|
|
|
Content-Type: text/x-csrc; charset=us-ascii |
|
Content-Disposition: attachment; filename="switch.c" |
|
|
|
int |
|
commutative_tree_code (int code) |
|
{ |
|
#define CASE(val, ret) case val:/* __asm__("# val="#val ",ret="#ret);*/ return ret; |
|
#ifndef CHAIN |
|
switch (code) |
|
{ |
|
# if 1 |
|
CASE(1,3) |
|
CASE(3,2) |
|
CASE(5,8) |
|
CASE(7,1) |
|
CASE(33,4) |
|
CASE(44,9) |
|
CASE(55,10) |
|
CASE(66,-1) |
|
CASE(77,99) |
|
CASE(666,0) |
|
# else |
|
case 1: |
|
return 3; |
|
case 3: |
|
return 2; |
|
case 5: |
|
return 8; |
|
case 7: |
|
return 1; |
|
case 33: |
|
return 4; |
|
case 44: |
|
return 9; |
|
case 55: |
|
return 10; |
|
case 66: |
|
return -1; |
|
case 77: |
|
return 99; |
|
case 666: |
|
return 0; |
|
# endif |
|
default: |
|
break; |
|
} |
|
return 4711; |
|
|
|
#else |
|
if (code == 1) |
|
return 3; |
|
else if (code == 3) |
|
return 2; |
|
else if (code == 5) |
|
return 8; |
|
else if (code == 7) |
|
return 1; |
|
else if (code == 33) |
|
return 4; |
|
else if (code == 44) |
|
return 9; |
|
else if (code == 55) |
|
return 10; |
|
else if (code == 66) |
|
return -1; |
|
else if (code == 77) |
|
return 99; |
|
else if (code == 666) |
|
return 0; |
|
else |
|
return 4711; |
|
#endif |
|
} |
|
|
|
|
|
--AhhlLboLdkugWU4S-- |
|
|
|
|