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add generated code 

llvm-svn: 22051
This commit is contained in:
Chris Lattner 2005-05-15 06:07:40 +00:00
parent 1a61fa460f
commit 55f987b45c
1 changed files with 24 additions and 6 deletions
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22
llvm/docs/ReleaseNotes.html
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@ -159,8 +159,26 @@ fastcc int %bar(int %X, int(double, int)* %FP) { ;<i> fastcc</i>
<p>In LLVM 1.5, the X86 code generator is the only target that has been enhanced
to support proper tail calls (other targets will be enhanced in future).
Further, because this support was added very close to the release, it is
disabled by default. Pass <tt>-enable-x86-fastcc</tt> to llc to enable it. X86
support will be enabled by default in the next LLVM release.</p>
disabled by default. Pass <tt>-enable-x86-fastcc</tt> to llc to enable it (this
will be enabled by default in the next release). The example above compiles to:
</p>
<p><pre>
bar:
sub ESP, 8 # Callee uses more space than the caller
mov ECX, DWORD PTR [ESP + 8] # Get the old return address
mov DWORD PTR [ESP + 4], 0 # First half of 0.0
mov DWORD PTR [ESP + 8], 0 # Second half of 0.0
mov DWORD PTR [ESP], ECX # Put the return address where it belongs
jmp EDX # Tail call "FP"
</pre></p>
<p>
With fastcc on X86, the first two integer arguments are passed in EAX/EDX, the
callee pops its arguments off the stack, and the argument area is always a
multiple of 8 bytes in size.
</p>
</div>
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