similar to: [LLVMdev] Restoring SSA form

> > Here's 'foo' is always called with positive value. However, the value > range > assigned to 'i' variable can be only [-inf, +inf], because uses of 'i' > outside of condition can get any value. So, I'd like to convert the > above to: > > i = 0; > if (i > 0) { > i = change_value_range(i); > foo(i); > } I

On 3/29/11 12:26 PM, George Baah wrote: > Hi All, > When I run the following command > llvm-gcc -03 -emit-llvm test.cpp -c -o test.bc or llvm-gcc -emit-llvm > test.cpp -c -o test.bc > > on the program test.cpp, the IR representation is not in SSA form. > I do not see any phi functions. Actually, it is in SSA form (or more precisely, the virtual registers are in SSA form;

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,

On Wed, 11 Jan 2006, Reid Spencer wrote: > llvm-as file.bc | opt -mem2reg | llvm-dis > file.ll llvm-as < file.bc | opt -mem2reg | llvm-dis > file.ll Note the extra "<". -Chris > On Wed, 2006-01-04 at 09:12 +0800, lizhuo wrote: >> meone tell me how to convert LLVM bytecode into minimal SSA form ? >> or just depend on GCC frontend ? > -Chris --

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

Dear All, Could someone tell me how to convert LLVM bytecode into minimal SSA form ? or just depend on GCC frontend ? thanks aqex

Hi All, When I run the following command llvm-gcc -03 -emit-llvm test.cpp -c -o test.bc or llvm-gcc -emit-llvm test.cpp -c -o test.bc on the program test.cpp, the IR representation is not in SSA form. I do not see any phi functions. program: test.cpp int main(int argc, char **argv) { int a[2],i,j; for(i=0;i<2;i++) { a[i] = i; } return a[1]; } Any clarifications will be

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

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

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; }

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

Hi Thanks for your answers so far. I am currently stumbling into new questions. Naive as i am, i thought that the llvm-bytecode is allways in SSA form. But this doesn't seem to be the case. At least there are no phi instructions embedded if the bytecode drops out of llvm-gcc? Looking into the archives this has been discussed before:

llvm-as file.bc | opt -mem2reg | llvm-dis > file.ll On Wed, 2006-01-04 at 09:12 +0800, lizhuo wrote: > meone tell me how to convert LLVM bytecode into minimal SSA form ? > or just depend on GCC frontend ? -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 189 bytes Desc: This is a digitally signed

Hi Simon, > I've read over the "LLVM Language Reference Manual" a few times, and > writing some ll code, but i'm stuck at a very basic point. How to > decrement a counter variable ? As Oscar pointed out, you need a phi-node. I read some of the published papers on LLVM before the Language Reference Manual and found them to be of use. You may also find Wikipedia's

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

I tried using the mem2reg pass with opt, e.g. opt -reg2mem x.bc > x2.bc where x.bc was produced with: llvm-gcc -O2 -emit-llvm -c x.c -o x.bc This did not reduce the # of variables in x2.bc I use -O2 because it produces the least # of instructions and hence the least # of new SSA virtual registers. Do you have a set of options to give to llvm-gcc or opt in mind ? My goal is to take a .c

Hi, I am interested in obtaining LLVM IR without any optimization performed on it.( IR obtained from cfrontend's AST). Is this LLVM IR in SSA form? Secondly, I want to make a transformation on this unoptimized IR, and convert it back to C. I believe llc -c does that. Thirdly, is it possible to use LLVM tool suite on LLVM IR that's not in SSA form, if we have such LLVM so.

On Wed, Jan 11, 2006 at 02:04:36PM -0600, Chris Lattner wrote: > On Wed, 11 Jan 2006, Reid Spencer wrote: > >llvm-as file.bc | opt -mem2reg | llvm-dis > file.ll > > llvm-as < file.bc | opt -mem2reg | llvm-dis > file.ll > > Note the extra "<". Strictly speaking, llvm-as converts .ll to .bc so that would be: llvm-as < input.ll | opt -mem2reg |

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