thomas@1461: Original patch from: ../4.3.2/160-flatten-switch-stmt-00.patch
thomas@1461: 
thomas@1461: -= BEGIN original header =-
thomas@1461: Original patch from gentoo: gentoo/src/patchsets/gcc/4.3.1/gentoo/18_all_904-flatten-switch-stmt-00.patch
thomas@1461: http://gcc.gnu.org/ml/gcc-patches/2007-04/msg00927.html
thomas@1461: 
thomas@1461: Hi,
thomas@1461: 
thomas@1461: The attached patch makes sure that we create smaller object code for
thomas@1461: simple switch statements. We just make sure to flatten the switch
thomas@1461: statement into an if-else chain, basically.
thomas@1461: 
thomas@1461: This fixes a size-regression as compared to gcc-3.4, as can be seen
thomas@1461: below.
thomas@1461: 
thomas@1461: 2007-04-15  Bernhard Fischer  <..>
thomas@1461: 
thomas@1461: 	* stmt.c (expand_case): Do not create a complex binary tree when
thomas@1461: 	optimizing for size but rather use the simple ordered list.
thomas@1461: 	(emit_case_nodes): do not emit jumps to the default_label when
thomas@1461: 	optimizing for size.
thomas@1461: 
thomas@1461: Not regtested so far.
thomas@1461: Comments?
thomas@1461: 
thomas@1461: Attached is the test switch.c mentioned below.
thomas@1461: 
thomas@1461: $ 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
thomas@1461: gcc-$i  -DCHAIN -Os -o switch-CHAIN-$i.o -c switch.c ;done
thomas@1461: $ 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
thomas@1461: gcc-$i  -UCHAIN -Os -o switch-$i.o -c switch.c ;done
thomas@1461: 
thomas@1461: $ size switch-*.o
thomas@1461:    text	   data	    bss	    dec	    hex	filename
thomas@1461:     169	      0	      0	    169	     a9	switch-2.95.o
thomas@1461:     115	      0	      0	    115	     73	switch-3.3.o
thomas@1461:     103	      0	      0	    103	     67	switch-3.4.o
thomas@1461:     124	      0	      0	    124	     7c	switch-4.0.o
thomas@1461:     124	      0	      0	    124	     7c	switch-4.1.o
thomas@1461:     124	      0	      0	    124	     7c	switch-4.2.orig-HEAD.o
thomas@1461:      95	      0	      0	     95	     5f	switch-4.3-HEAD.o
thomas@1461:     124	      0	      0	    124	     7c	switch-4.3.orig-HEAD.o
thomas@1461:     166	      0	      0	    166	     a6	switch-CHAIN-2.95.o
thomas@1461:     111	      0	      0	    111	     6f	switch-CHAIN-3.3.o
thomas@1461:      95	      0	      0	     95	     5f	switch-CHAIN-3.4.o
thomas@1461:      95	      0	      0	     95	     5f	switch-CHAIN-4.0.o
thomas@1461:      95	      0	      0	     95	     5f	switch-CHAIN-4.1.o
thomas@1461:      95	      0	      0	     95	     5f	switch-CHAIN-4.2.orig-HEAD.o
thomas@1461:      95	      0	      0	     95	     5f	switch-CHAIN-4.3-HEAD.o
thomas@1461:      95	      0	      0	     95	     5f	switch-CHAIN-4.3.orig-HEAD.o
thomas@1461: 
thomas@1461: 
thomas@1461: Content-Type: text/x-diff; charset=us-ascii
thomas@1461: Content-Disposition: attachment; filename="gcc-4.3.gcc-flatten-switch-stmt.00.diff"
thomas@1461: 
thomas@1461: -= END original header =-
thomas@1461: 
thomas@1461: diff -durN gcc-4.3.3.orig/gcc/stmt.c gcc-4.3.3/gcc/stmt.c
thomas@1461: --- gcc-4.3.3.orig/gcc/stmt.c	2008-05-09 20:12:13.000000000 +0200
thomas@1461: +++ gcc-4.3.3/gcc/stmt.c	2009-01-27 22:19:28.000000000 +0100
thomas@1461: @@ -2509,7 +2509,11 @@
thomas@1461:  	  use_cost_table
thomas@1461:  	    = (TREE_CODE (orig_type) != ENUMERAL_TYPE
thomas@1461:  	       && estimate_case_costs (case_list));
thomas@1461: -	  balance_case_nodes (&case_list, NULL);
thomas@1461: +	  /* When optimizing for size, we want a straight list to avoid
thomas@1461: +	     jumps as much as possible. This basically creates an if-else
thomas@1461: +	     chain.  */
thomas@1461: +	  if (!optimize_size)
thomas@1461: +	    balance_case_nodes (&case_list, NULL);
thomas@1461:  	  emit_case_nodes (index, case_list, default_label, index_type);
thomas@1461:  	  emit_jump (default_label);
thomas@1461:  	}
thomas@1461: @@ -3067,6 +3071,7 @@
thomas@1461:  	    {
thomas@1461:  	      if (!node_has_low_bound (node, index_type))
thomas@1461:  		{
thomas@1461: +		  if (!optimize_size) /* don't jl to the .default_label. */
thomas@1461:  		  emit_cmp_and_jump_insns (index,
thomas@1461:  					   convert_modes
thomas@1461:  					   (mode, imode,