similar to: [LLVMdev] How to insert phi

Chayan Sarkar wrote: > Hi, > I am new to llvm. I have project in llvm. For that I need SSA form, > which is already implemented in llvm. Basically I want to know which > pass insert phi and converts it to SSA form in llvm . http://llvm.org/docs/Passes.html#mem2reg which is lib/Transforms/Utils/PromoteMemoryToRegister.cpp. Nick

But, the mem2reg pass removes all load store instructions. It replaces all variables by their if possible (kind of constant propagation). I have generated the bitcode of the source program and the applied the mem2reg pass and obviously not getting desired thing. What I want is convert it into SSA form without replacing any variable by their constant value. Please elaborate on your point. Also,

E-path PRE requires the program in SSA form like SSAPRE algorithm. Then it finds the eliminatable path (e-path) for an expression and converts partially redundant to fully redundant and removes redundancy Chayan On Mon, Jun 7, 2010 at 1:58 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Sun, Jun 6, 2010 at 8:56 PM, Chayan Sarkar <chayan.ju at gmail.com> wrote: >> Hi

There is no existing pass to do this in LLVM, mostly because it wouldn't be useful for optimizing programs. From your input, mem2reg produces: define i32 @myfunc(i32 %x, i32 %y) nounwind { entry: %cmp = icmp sgt i32 %x, %y ; <i1> [#uses=1] br i1 %cmp, label %if.then, label %if.else if.then: ; preds = %entry %add = add

Suppose my Input function is like : myfunc(int x,int y){ int a=2, b=3,c=5; if(x>y) { c=a+b; a=6; } else { c=a*b; b=4; } a=c+a; c=a+b; } and the output should be : myfunc(int x,int y){ int a.0=2, b.0=3,c.0=5; if(x>y) { c.1=a.0+b.0; a.1=6; } else { c.2=a.0*b.0; b.1=4; }

Hi Jeffrey, Actually I am trying to implement "E-path PRE" which is based on non-algebric equivallence. So, the variable names need to be preserved. You said that I need to insert these to preserve variable %a.0 = bitcast i32 2 to i32 So, these need to be inserted before the mem2reg pass or within the pass. In first case, how to call an inbuilt pass after doing some analysis from my

Hi, Can anyone tell me, whether it is possible to convert a program into SSA form without considering algebric equivalence ? regards, Chayan

You can use STOREs and LOADs on memory and then use mem2reg pass. 2010/6/1 Chayan Sarkar <chayan.ju at gmail.com>: > Hi, > > Can anyone tell me, whether it is possible to convert a program into > SSA form without considering algebric equivalence ? > > regards, > Chayan > _______________________________________________ > LLVM Developers mailing list > LLVMdev at

On Sun, Jun 6, 2010 at 8:56 PM, Chayan Sarkar <chayan.ju at gmail.com> wrote: > Hi Jeffrey, > > Actually I am trying to implement "E-path PRE" which is based on > non-algebric equivallence. So, the  variable names need to be > preserved. Then why do you want to run mem2reg before your optimization in the first place? -Eli

On Sat, Jun 5, 2010 at 2:03 AM, Chayan Sarkar <chayan.ju at gmail.com> wrote: > But, the mem2reg pass removes all load store instructions. It replaces > all variables by their if possible (kind of constant propagation). I > have generated the bitcode of the source program and the applied the > mem2reg pass and obviously not getting desired thing. > > What I want is convert

Hi All, Still I could not figure out how to use Pass* while calling SplitEdge() function. Can anyone provide me some example? Regards, Chayan On Sun, Jul 18, 2010 at 11:49 PM, Nick Lewycky <nicholas at mxc.ca> wrote: > Chayan Sarkar wrote: >> >> Hi, >> >> I have tried to use SplitEdge function, but failed. Actually the third >> parameter is a variable of

Hi, I could not figure out, how to declare a Pass*. Can anyone give me an example, how to use SplitEdge() function ? Please help me out. Regards, Chayan On Tue, Jul 20, 2010 at 10:12 AM, Chayan Sarkar <chayan.ju at gmail.com> wrote: > Hi All, > > Still I could not figure out how to use Pass* while calling > SplitEdge() function. Can anyone provide me some example? > >

Hi, I have tried to use SplitEdge function, but failed. Actually the third parameter is a variable of type Pass and it need to be non-null. But I could not figure out how to use it. Please help me out. Regards, Chayan On Sat, Jul 17, 2010 at 10:16 PM, Nick Lewycky <nicholas at mxc.ca> wrote: > Chayan Sarkar wrote: >> >> Hi all, >> >> Suppose in a CFG bb1 has two

Chayan Sarkar wrote: > Hi, > > I have tried to use SplitEdge function, but failed. Actually the third > parameter is a variable of type Pass and it need to be non-null. But I > could not figure out how to use it. Please help me out. The only reason it needs a non-NULL Pass* is to call llvm::SplitBlock which uses P->getAnalysisIfAvailable unconditionally. Feel free to wrap

Hi, I am trying to write a small pass. In my pass, I have inserted some instruction and used that in another. But, during OPT it is showing "Instruction does not dominate all uses" like following - %b.1 = bitcast i32 4 to i32 ; <i32> [#uses=8] %11 = add i32 %a.1, %b.1 ; <i32> [#uses=1]Instruction does not dominate all uses! Any

Hi all, Suppose in a CFG bb1 has two succesor bb3 and bb4, and bb3 has two predecessor bb1 and bb2. Now how can I insert a basic block between bb1 and bb3 that at the edge bb1-->bb3 . In general how can I insert a basic block on an edge? Regards, Chayan

Simply create an undef constant value and add a store instruction to store the undef value into the memory allocated by the alloca. I believe there is an llvm::Undef class. Check doxygen docs for details. -----Original Message----- From: Chayan Sarkar <chayan.ju at gmail.com> Sent: Sunday, June 27, 2010 12:05 PM To: llvmdev at cs.uiuc.edu <llvmdev at cs.uiuc.edu>; chayan.ju at

Chayan Sarkar wrote: > Hi all, > > Suppose in a CFG bb1 has two succesor bb3 and bb4, and bb3 has two > predecessor bb1 and bb2. Now how can I insert a basic block between > bb1 and bb3 that at the edge bb1-->bb3 . > > In general how can I insert a basic block on an edge? Use llvm::SplitEdge in Transforms/Utils/BasicBlockUtils.h. The technique is to create a new bb with a

Chayan Sarkar wrote: > Hi, > > I am trying to write a small pass. In my pass, I have inserted some > instruction and used that in another. But, during OPT it is showing > "Instruction does not dominate all uses" like following - > > %b.1 = bitcast i32 4 to i32 ; <i32> [#uses=8] %11 > = add i32 %a.1, %b.1 ;

Hi, I am emitting llvm bit code using llvm-gcc -c -emit-llvm -O0 -o test.bc test.c and then optimizing it with opt -O3 -print-module test.bc in order to obtain a dump of generated IR. The resulting code has Phi nodes and is perhaps in SSA form. I want to undo the SSA form while retaining all the other optimizations. Is mem2reg the right optimization to be added after -O3, i.e., opt -O3