patches/gcc/4.3.1/160-flatten-switch-stmt-00.patch
author Michael Hope <michael.hope@linaro.org>
Wed Oct 19 15:27:32 2011 +1300 (2011-10-19)
changeset 2739 f320e22f2cba
parent 746 b150d6f590fc
permissions -rw-r--r--
arch: add softfp support

Some architectures support a mixed hard/soft floating point, where
the compiler emits hardware floating point instructions, but passes
the operands in core (aka integer) registers.

For example, ARM supports this mode (to come in the next changeset).

Add support for softfp cross compilers to the GCC and GLIBC
configuration. Needed for Ubuntu and other distros that are softfp.

Signed-off-by: Michael Hope <michael.hope@linaro.org>
[yann.morin.1998@anciens.enib.fr: split the original patch]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
     1 Original patch from gentoo: gentoo/src/patchsets/gcc/4.3.1/gentoo/18_all_904-flatten-switch-stmt-00.patch
     2 http://gcc.gnu.org/ml/gcc-patches/2007-04/msg00927.html
     3 
     4 Hi,
     5 
     6 The attached patch makes sure that we create smaller object code for
     7 simple switch statements. We just make sure to flatten the switch
     8 statement into an if-else chain, basically.
     9 
    10 This fixes a size-regression as compared to gcc-3.4, as can be seen
    11 below.
    12 
    13 2007-04-15  Bernhard Fischer  <..>
    14 
    15 	* stmt.c (expand_case): Do not create a complex binary tree when
    16 	optimizing for size but rather use the simple ordered list.
    17 	(emit_case_nodes): do not emit jumps to the default_label when
    18 	optimizing for size.
    19 
    20 Not regtested so far.
    21 Comments?
    22 
    23 Attached is the test switch.c mentioned below.
    24 
    25 $ 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
    26 gcc-$i  -DCHAIN -Os -o switch-CHAIN-$i.o -c switch.c ;done
    27 $ 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
    28 gcc-$i  -UCHAIN -Os -o switch-$i.o -c switch.c ;done
    29 
    30 $ size switch-*.o
    31    text	   data	    bss	    dec	    hex	filename
    32     169	      0	      0	    169	     a9	switch-2.95.o
    33     115	      0	      0	    115	     73	switch-3.3.o
    34     103	      0	      0	    103	     67	switch-3.4.o
    35     124	      0	      0	    124	     7c	switch-4.0.o
    36     124	      0	      0	    124	     7c	switch-4.1.o
    37     124	      0	      0	    124	     7c	switch-4.2.orig-HEAD.o
    38      95	      0	      0	     95	     5f	switch-4.3-HEAD.o
    39     124	      0	      0	    124	     7c	switch-4.3.orig-HEAD.o
    40     166	      0	      0	    166	     a6	switch-CHAIN-2.95.o
    41     111	      0	      0	    111	     6f	switch-CHAIN-3.3.o
    42      95	      0	      0	     95	     5f	switch-CHAIN-3.4.o
    43      95	      0	      0	     95	     5f	switch-CHAIN-4.0.o
    44      95	      0	      0	     95	     5f	switch-CHAIN-4.1.o
    45      95	      0	      0	     95	     5f	switch-CHAIN-4.2.orig-HEAD.o
    46      95	      0	      0	     95	     5f	switch-CHAIN-4.3-HEAD.o
    47      95	      0	      0	     95	     5f	switch-CHAIN-4.3.orig-HEAD.o
    48 
    49 
    50 Content-Type: text/x-diff; charset=us-ascii
    51 Content-Disposition: attachment; filename="gcc-4.3.gcc-flatten-switch-stmt.00.diff"
    52 
    53 diff -durN gcc-4.3.1.orig/gcc/stmt.c gcc-4.3.1/gcc/stmt.c
    54 --- gcc-4.3.1.orig/gcc/stmt.c	2008-05-09 20:12:13.000000000 +0200
    55 +++ gcc-4.3.1/gcc/stmt.c	2008-06-10 14:57:58.000000000 +0200
    56 @@ -2509,7 +2509,11 @@
    57  	  use_cost_table
    58  	    = (TREE_CODE (orig_type) != ENUMERAL_TYPE
    59  	       && estimate_case_costs (case_list));
    60 -	  balance_case_nodes (&case_list, NULL);
    61 +	  /* When optimizing for size, we want a straight list to avoid
    62 +	     jumps as much as possible. This basically creates an if-else
    63 +	     chain.  */
    64 +	  if (!optimize_size)
    65 +	    balance_case_nodes (&case_list, NULL);
    66  	  emit_case_nodes (index, case_list, default_label, index_type);
    67  	  emit_jump (default_label);
    68  	}
    69 @@ -3067,6 +3071,7 @@
    70  	    {
    71  	      if (!node_has_low_bound (node, index_type))
    72  		{
    73 +		  if (!optimize_size) /* don't jl to the .default_label. */
    74  		  emit_cmp_and_jump_insns (index,
    75  					   convert_modes
    76  					   (mode, imode,