diff -r 35b30f8fb307 -r 5dd0b83ae528 patches/gcc/4.3.5/160-flatten-switch-stmt-00.patch --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/patches/gcc/4.3.5/160-flatten-switch-stmt-00.patch Sun Sep 19 18:37:18 2010 +0200 @@ -0,0 +1,81 @@ +Original patch from: ../4.3.2/160-flatten-switch-stmt-00.patch + +-= BEGIN original header =- +Original patch from gentoo: gentoo/src/patchsets/gcc/4.3.1/gentoo/18_all_904-flatten-switch-stmt-00.patch +http://gcc.gnu.org/ml/gcc-patches/2007-04/msg00927.html + +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" + +-= END original header =- + +diff -durN gcc-4.3.3.orig/gcc/stmt.c gcc-4.3.3/gcc/stmt.c +--- gcc-4.3.3.orig/gcc/stmt.c 2008-05-09 20:12:13.000000000 +0200 ++++ gcc-4.3.3/gcc/stmt.c 2009-01-27 22:19:28.000000000 +0100 +@@ -2509,7 +2509,11 @@ + 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); + } +@@ -3067,6 +3071,7 @@ + { + 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,