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-rw-r--r--toolchain/gcc/patches/4.2.4/904-flatten-switch-stmt-00.patch74
1 files changed, 74 insertions, 0 deletions
diff --git a/toolchain/gcc/patches/4.2.4/904-flatten-switch-stmt-00.patch b/toolchain/gcc/patches/4.2.4/904-flatten-switch-stmt-00.patch
new file mode 100644
index 0000000..f33f8e7
--- /dev/null
+++ b/toolchain/gcc/patches/4.2.4/904-flatten-switch-stmt-00.patch
@@ -0,0 +1,74 @@
+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-4.2.3/gcc/stmt.c
+===================================================================
+--- gcc-4.2.3.orig/gcc/stmt.c 2007-09-01 17:28:30.000000000 +0200
++++ gcc-4.2.3/gcc/stmt.c 2008-05-21 13:45:59.137288494 +0200
+@@ -2511,7 +2511,11 @@
+ 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);
+ }
+@@ -3069,6 +3073,7 @@
+ {
+ 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,