[Patch,wwwdocs,AVR]: AVR release notes

[Georg-Johann Lay]

Adding AVR-specific release notes to wwwdocs/htdocs/gcc-4.7/changes.html

Ok?

Johann

Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.7/changes.html,v
retrieving revision 1.73
diff -u -r1.73 changes.html
--- changes.html	12 Jan 2012 19:35:29 -0000	1.73
+++ changes.html	20 Jan 2012 18:29:39 -0000
@@ -45,6 +45,11 @@
     <code>-compat-bsd</code> compiler option is not recognized any
     longer.</li>
 
+    <li>The AVR port's libgcc has been improved and its multilib structure
+      has been enhanced.  As a result, all objects contributing to an
+      application must either be compiled with GCC versions up to 4.6.x or
+      with GCC versions &ge;&nbsp;4.7.</li>
+      
     <li>The ARM port's <code>-mwords-little-endian</code> option has
     been deprecated.  It will be removed in a future release.</li>
 
@@ -530,6 +535,40 @@
 
 <h2 id="targets">New Targets and Target Specific Improvements</h2>
 
+<h3 id="avr">AVR</h3>
+  <ul>
+    <li>Support has beed added for instrinsic named address spaces
+    <code>__pgm</code>, <code>__pgm1</code>,&nbsp;&hellip;, <code>__pgm5</code>
+    and <code>__pgmx</code>.  These address spaces locate read-only data in
+    flash memory and allow reading from flash memory by means of vanilla
+    C&nbsp;instructions, i.e. without the need of (inline) assembler code.</li>
+    <li>Support for AVR-specific built-in functions has beed added.</li>
+    <li>Support has beed added for the built-in, 24-bit, signed and unsigned
+      integer types <code>__int24</code> and <code>__uint24</code>.</li>
+    <li>New command-line options <code>-maccumulate-args</code>,
+      <code>-mbranch-cost=<i>cost</i></code> and <code>-mstrict-X</code>
+      were added to allow better fine-tuning of code optimization.</li>
+    <li>Many optimizations to:
+      <ul>
+	<li>64-bit integer arithmetic</li>
+	<li>Widening multiplication</li>
+	<li>Integer divide-by-constant</li>
+	<li>Generic built-in functions
+	  like <code>__builtin_ffs*</code>, <code>__builtin_clz*</code>,&nbsp;etc.</li>
+	<li>If-else decision trees generated by <code>switch</code> instructions</li>
+	<li>Merging of data in <code>.progmem</code></li>
+	<li>Devices with 8-bit wide stack pointer register</li>
+	<li>&hellip;</li>
+      </ul>
+    <li>Better documentation:
+      <ul>
+	<li>Handling of <code>EIND</code> and indirect jumps on devices with
+	  more than 128&nbsp;KiB of program memory.</li>
+	<li>AVR-specific built-in macros.</li>
+      </ul>
+    </li>
+  </ul>
+
 <h3 id="arm">ARM</h3>
   <ul>
     <li>GCC now supports the Cortex-A7 processor implementing the