[llvm-commits] [llvm] r45141 - /llvm/trunk/lib/Target/README.txt

[Christopher Lamb]

Hopefully fixed by http://lists.cs.uiuc.edu/pipermail/llvm-commits/ 
Week-of-Mon-20071217/056446.html

This is my first attempt hacking on Transforms, so some of the idioms  
were a little new to me. Hope the patch looks OK! =)

On Dec 17, 2007, at 5:19 PM, Chris Lattner wrote:

> Author: lattner
> Date: Mon Dec 17 19:19:18 2007
> New Revision: 45141
>
> URL: http://llvm.org/viewvc/llvm-project?rev=45141&view=rev
> Log:
> add a missed case.
>
> Modified:
>     llvm/trunk/lib/Target/README.txt
>
> Modified: llvm/trunk/lib/Target/README.txt
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ 
> README.txt?rev=45141&r1=45140&r2=45141&view=diff
>
> ====================================================================== 
> ========
> --- llvm/trunk/lib/Target/README.txt (original)
> +++ llvm/trunk/lib/Target/README.txt Mon Dec 17 19:19:18 2007
> @@ -464,3 +464,21 @@
>  }
>
>  // 
> ===------------------------------------------------------------------- 
> --===//
> +
> +This code is often produced by the SMAX expansion in SCEV:
> +
> +define i32 @foo(i32 %a) {
> +entry:
> +        %tmp15 = sub i32 99, %a         ; <i32> [#uses=2]
> +        %tmp16 = icmp slt i32 %tmp15, 0         ; <i1> [#uses=1]
> +        %smax = select i1 %tmp16, i32 0, i32 %tmp15             ;  
> <i32> [#uses=1]
> +        %tmp12 = add i32 %smax, %a              ; <i32> [#uses=1]
> +        %tmp13 = add i32 %tmp12, 1              ; <i32> [#uses=1]
> +        ret i32 %tmp13
> +}
> +
> +Note that the tmp12 add can be pushed through the select operands,  
> turning
> +it into a "select %tmp16, %a, 99".  We apparently already do this  
> in dag
> +combine because it isn't present in X86 output.
> +
> +// 
> ===------------------------------------------------------------------- 
> --===//
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

--
Christopher Lamb



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20071218/956fb991/attachment.html>