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checkpoint, the release notes are now feature complete.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115495 91177308-0d34-0410-b5e6-96231b3b80d8
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Chris Lattner 2010-10-04 04:39:25 +00:00
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@ -742,8 +742,9 @@ it run faster:</p>
<li>A new (experimental) "-rendermf" pass is available which renders a
MachineFunction into HTML, showing live ranges and other useful
details.</li>
<!--New SubRegIndex tblgen class for targets -> jakob -->
<li>The new SubRegIndex tablegen class allows subregisters to be indexed
symbolically instead of numerically. If your target uses subregisters you
will need to adapt to use SubRegIndex when you upgrade to 2.8.</li>
<!-- SplitKit -->
<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten
@ -760,7 +761,7 @@ it run faster:</p>
</div>
<div class="doc_text">
<p>New features of the X86 target include:
<p>New features and major changes in the X86 target include:
</p>
<ul>
@ -768,30 +769,38 @@ it run faster:</p>
in registers across basic blocks, dramatically improving performance of code
that uses long double, and when targetting CPUs that don't support SSE.</li>
New SSEDomainFix pass:
On Nehalem and newer CPUs there is a 2 cycle latency penalty on using a
register in a different domain than where it was defined. Some instructions
have equvivalents for different domains, like por/orps/orpd. The
SSEDomainFix pass tries to minimize the number of domain crossings by
changing between equvivalent opcodes where possible.
<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On
Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on
using a register in a different domain than where it was defined. This pass
optimizes away these stalls.</li>
X86 backend attempts to promote 16-bit integer operations to 32-bits to avoid
0x66 prefixes, which are slow on some microarchitectures and bloat the code
on others.
<li>The X86 backend now promote 16-bit integer operations to 32-bits when
possible. This avoids 0x66 prefixes, which are slow on some
microarchitectures and bloat the code on all of them.</li>
New support for X86 "thiscall" calling convention (x86_thiscallcc in IR) for windows.
<li>The X86 backend now supports the Microsoft "thiscall" calling convention,
and a <a href="LangRef.html#callingconv">calling convention</a> to support
<a href="#GHC">ghc</a>.</li>
New llvm.x86.int intrinsic (for int $42 and int3)
<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto
the X86 "int $42" and "int3" instructions.</li>
Verbose assembly decodes X86 shuffle instructions, e.g.:
insertps $113, %xmm3, %xmm0 ## xmm0 = zero,xmm0[1,2],xmm3[1]
unpcklps %xmm1, %xmm0 ## xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
pshufd $1, %xmm1, %xmm1 ## xmm1 = xmm1[1,0,0,0]
<li>At the IR level, the &lt;2 x float&gt; datatype is now promoted and passed
around as a &lt;4 x float&gt; instead of being passed and returns as an MMX
vector. If you have a frontend that uses this, please pass and return a
&lt;2 x i32&gt; instead (using bitcasts).</li>
<li>When printing .s files in verbose assembly mode (the default for clang -S),
the X86 backend now decodes X86 shuffle instructions and prints human
readable comments after the most inscrutible of them, e.g.:
<pre>
insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i>
unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i>
pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i>
</pre>
</li>
X86 ABI: <2 x float> in IR no longer maps onto MMX, it turns into <4 x float>
new GHC calling convention
</ul>
</div>
@ -806,14 +815,21 @@ it run faster:</p>
</p>
<ul>
<li>The ARM backend now optimizes tail calls into jumps.</li>
<li>Scheduling is improved through the new list-hybrid scheduler as well
as through better modeling of structural hazards.</li>
<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now
supported.</li>
<li>NEON support has been improved to model instructions which operate onto
multiple consequtive registers more aggressively. This avoids lots of
extraneous register copies.</li>
<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several
global variables into one, saving extra address computation (all the global
variables can be accessed via same base address) and potentially reducing
register pressure.</li>
NEON: Better performance for QQQQ (4-consecutive Q register) instructions. New reg sequence abstraction?
ARM: Better scheduling (list-hybrid, hybrid?)
ARM: Tail call support.
ARM: General performance work and tuning.
ARM: Half float support through intrinsics LangRef.html#int_fp16
<li>ARMGlobalMerge: <!-- Anton --> </li>
<li>The ARM has received many minor improvements and tweaks which lead to
substantially better performance in a wide range of different scenarios.</li>
<li>The ARM NEON intrinsics have been substantially reworked to reduce
redundancy and improve code generation. Some of the major changes are:
@ -863,23 +879,10 @@ it run faster:</p>
</li>
</ol>
</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="otherimprovements">Other Improvements and New Features</a>
</div>
<div class="doc_text">
<p>Other miscellaneous features include:</p>
<ul>
<li></li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">