similar to: [LLVMdev] Question to Chris

Dear Prof.Adve and Bill, I deeply appreciate your comments and concerns. (Please forgive my late response. I've tried some more cases to make this issue) As Prof.Adve mentioned, I need to explain exactly what my problem is, but I have no good ability that I can explain it in this plain text space. For this reason, I made a .pdf file and linked it as follows:

Wow... Thank you so much for this. I'll try this one. Thanks again, Wojciech. SJL ---- Original message ---- >Date: Sat, 15 Sep 2007 15:07:34 +0200 >From: Wojciech Matyjewicz <wmatyjewicz at fastmail.fm> >Subject: Re: [LLVMdev] constructing 'for' statement from LLVM bitcode >To: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu> > >Hi, >

Dear Wojciech Matyjewicz: Thank you for your advice. I could follow what you had suggested upto opt -analyze -loops bsloop-opt.bc Therefore, I could get the prints you had showed me as follows: -------------------------------------------------------- Printing analysis 'Natural Loop Construction' for function 'bsloop': Loop Containing: %bb16, %bb13, %bb8, %bb1 Loop

Hello, guys. I just tested -reg2mem pass to see how it changes my bitcode. E.g., for the following simple C code: ------------------------------------------------------------- int foo() { int i,j; int sum = 0; for (i=0; i<10; i++) { sum += i; for (j=0; j<3; j++) sum += 2; } return sum; } ------------------------------------------------------------- I could get the

Ok, here are a few suggestions and comments: 1) LLVM has the capabilities to do everything that you are trying to re-implement. 2) Have you looked at the C backend? It recreates loops. It may not create "for" loops but you can hack on it to do that. 3) The way you are converting out of SSA is wrong. You will suffer from lost copies. You should look at using demotePHI(). see

I appreciate your suggestions, some follow-up questions though.... >1) LLVM has the capabilities to do everything that you are trying to >re-implement. >2) Have you looked at the C backend? It recreates loops. It may not >create "for" loops but you can hack on it to do that. I wonder if you mean "goto elimination technique" by Ana Maria Erosa (

Thank you for this comment, Mike. So... your suggestion is to make a valid transform for each loop like: >for (;C;) { > S >} > >is to transform: > >top: >if (!C) goto end; > S >goto top; >end: For now, my code is incomplete so not ready to present for audit yet but I hope it asap. In fact, I couldn't understand what you said: >The cost of the .pdf

I didn't 'cause my llvm-gcc just seems to be 4.0: ]$ llvm-gcc -v Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../llvm-gcc4-1.9.source/configure --prefix=/mounts/zion/disks/0/localhome/tbrethou/llvm-gcc4/obj/../install --enable-llvm=/localhome/tbrethou/llvm --enable-languages=c,c++ --disable-threads Thread model: single gcc version 4.0.1 LLVM (Apple Computer, Inc. build

Hello. I updated my LLVM with version 2.1 from 1.9. But I am curious why I still have signed integer type. I still get LLVM IR as follows: ...... ...... bb8.outer: ; preds = %bb10, %entry %i.0.0.ph = phi uint [ 0, %entry ], [ %indvar.next26, %bb10 ] ; <uint> [#uses=2] %sum.0.pn.ph = phi uint [ 0, %entry ], [ %sum.1, %bb10 ] ; <uint> [#uses=1] br label %bb8 bb3: ; preds = %bb8

Do you mean that "normal" SSA phi elimination algorithm is DemotePHI()? Thx, Seung ---- Original message ---- >Date: Mon, 24 Mar 2008 21:43:06 -0700 >From: Chris Lattner <sabre at nondot.org> >Subject: Re: [LLVMdev] What is "strong phi elimination" >To: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu> >Cc: Christopher Lamb

Hello, guys. I am trying to construct higher-level 'for' from the low-level LLVM bitcode(ver 1.9). It's partly successful thanks to David A. Greene's advice suggested to use Control Dependence Graph(CDG). I could find which BB contributes to form which loop with CDG. For example, for this simple function: ----------------------------------------------------------- void bsloop(int

Wojtek Matyjewicz has written a simple DependenceAnalysis interface and sent email about it to llvmdev in June -- the message is attached. He said he wrote several tests behind that interface -- ZIV, strong SIV, Banerjee, and some form of the Delta test -- and two students in my Spring class added the Omega test. I have not reviewed his interface yet because I've been traveling

Bill, Depending on what Seung's problem is, converting *out* of SSA form may actually be the wrong thing to do. Seung needs to explain exactly problem he is unable solve using SSA form. --Vikram http://www.cs.uiuc.edu/~vadve http://llvm.org/ On Jan 28, 2008, at 1:10 AM, Bill Wendling wrote: > Hi Seung, > > It should be fairly straight-forward to do in LLVM. Once you

Hi Seung, It should be fairly straight-forward to do in LLVM. Once you identify the loops, then identify the PHI nodes that you need to convert, then apply the transformation below. The fine details on how to create an instruction and replace one instruction with another are documented in the docs section and in other code. :-) One thing to be careful of, if you convert a variable like

Wojtek, If you like, I can help guide this SoC project. I would also like to see if we can coordinate with Alex and Albert, who are doing the class project here. As a first comment, your 3 layers are a good organization but two comments: 1. Layer 1 shd also look at loop bounds and array bounds: those can be used to disprove some deps. 2. The interface will also need to compute direction and

Hello, guys. I just wonder if there is any way to spit out LLVM assembly without any basic block division. E.g., If I emit LLVM assembly for the following simple code: ------------------------------------------------------------ void f_loop(long* c, long sz) { long i; for (i = 0; i < sz; i++) { long offset = i * sz; long* out = c + offset; out[i] = 0; } }

Hi, guys. Is there any easy way to know the leaf BB node in the CFG which is not terminated by such a 'br' instruction? E.g., for the following LLVM assembly: ----------------------------------------------------------- int %foo2(int %k) { entry: br label %bb bb: ; preds = %bb, %entry %indvar = phi uint [ 0, %entry ], [ %indvar.next, %bb ] ;

Thank you for this reply. However, I've already read this thesis. (Mr. Doug Simon in Sun microsystems I mentioned was her student.) This is a quite good article for reverse engineering but this is only useful for my alternative way which is trying to derive HL code from a machine assembly. This thesis is a little bit old before SSA form becomes quite popular so does not deal with any PHI

Thank you, Bill. Seems to be better. Anyway...Is there a way I can do what you showed for me? Thanks, Seung J. Lee ---- Original message ---- >Date: Sat, 26 Jan 2008 22:10:01 -0800 >From: Bill Wendling <isanbard at gmail.com> >Subject: Re: [LLVMdev] Question to Chris >To: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu> > >On Jan 26, 2008, at 9:48 AM, Seung

Dear Dr.Lattner Hello, Dr.Lattner. You may find your reply at http://lists.cs.uiuc.edu/pipermail/llvmdev/2007-August/010479.html and other your replies to me right up and down at the list. You had suggested me to read the "structural analysis" section in Muchnick's book. Thank you for this. I bought and read it, which was very helpful but... I still don't have any idea