search for: reg2mem

Is there a pass I can use after reg2mem to get rid of occurances like this?: store i32 %cond, i32* %cond.reg2mem %cond.reload = load i32* %cond.reg2mem store i32 %cond.reload, i32* %cond4.reg2mem Essentially, in this case, reg2mem creates an extra memory space to store and load a value from just here, and never uses the value aga...

Hello Tobi, You are right, we need to run some other passes before running the scalar evolution pass. The sequence that I run for this example is -O3 -loop-simplify -reg2mem.  This is why I did not obtain the expressions depending on the loop indices. So I removed the reg2mem pass and scalar evolution computes the correct functions. However, I need to run the reg2mem pass (or any other that would eliminate the phi nodes) before calling my own passes. So probably we...

Hi, I work on a pass that requires as input LLVM code without any phi nodes. For this, I use the reg2mem pass which produces suitable code, the pass runs correctly, but I obtain a significant performance decrease. I expect that this is because there are more reads / writes to memory after running the reg2mem pass. How can I optimize the code, without inserting any phi nodes? Or is there a better s...

I am currently building a BasicBlock pass which requires to run -reg2mem before it, and need to run -mem2reg after it to clean up. So, I want to specify -reg2mem as one of the pre-requisite passes to it, as: class MyPass: public BasicBlockPass{ virtual void getAnalysisUsage(AnalysisUsage &AU){ ... AU.addRequired<RegToMem>(); ... } }; I...

Hello, I have two for loops (one inside the other), that after indvars, looprotate, etc. (the important here is the loop rotate), is similar to this (I've stripped the real operations): define i32 @f() nounwind { entry: br label %bb1 bb1: ; preds = %bb3, %bb1, %entry %i.0.reg2mem.0.ph = phi i32 [ 0, %entry ], [ %i.0.reg2mem.0.ph, %bb1 ], [ %indvar.next9, %bb3 ] ; <i32> [#uses=4] %j.0.reg2mem.0 = phi i32 [ 0, %entry ], [ %indvar.next, %bb1 ], [ 0, %bb3 ] ; <i32> [#uses=3] %indvar.next = add i32 %j.0.reg2mem.0, 1 ; <i32> [#uses=2...

Hi, when I delete some instruction, I got some error prompt message. - %i.0.reg2mem.0 = phi i32 [ 0, %bb5 ], [ %indvar.next, %bb12 ] ; <i32> [#uses=2] - %s.0.reg2mem.0 = phi i32 [ 0, %bb5 ], [ %tmp16, %bb12 ] ; <i32> [#uses=1] - %tmp14 = tail call i32 @foobar(i32 %i.0.reg2mem.0) nounwind ; <i32> [#uses=1] - %tmp16 = add i32 %tmp14, %s.0.reg2mem.0 ; &lt...

On 08/03/2011 08:35 AM, Jimborean Alexandra wrote: > Hello Tobi, > > You are right, we need to run some other passes before running the > scalar evolution pass. The sequence that I run for this example is -O3 > -loop-simplify -reg2mem. This is why I did not obtain the expressions > depending on the loop indices. So I removed the reg2mem pass and scalar > evolution computes the correct functions. > > However, I need to run the reg2mem pass (or any other that would > eliminate the phi nodes) before calling my own pa...

I guess AU.addRequiredID(DemoteRegisterToMemoryID) would do the trick. - xi On Jun 19, 2011, at 11:03 PM, Chuck Zhao wrote: > I am currently building a BasicBlock pass which requires to run -reg2mem before it, and need to run -mem2reg after it to clean up. > > So, I want to specify -reg2mem as one of the pre-requisite passes to it, as: > > > class MyPass: public BasicBlockPass{ > > virtual void getAnalysisUsage(AnalysisUsage &AU){ > ... > AU.addRequ...

Might have to do with GVN's PRE (partial redundancy elimination), which tends to increase code size. H. ----- Original Message ----- From: Abhinash Jain Sent: 09/22/13 01:17 AM To: llvmdev at cs.uiuc.edu Subject: [LLVMdev] Why total number of store instructions increased in case of gvn with reg2mem? Below are the 4 cases out of which for the first 3 cases am able to understand the variation on total number of store inst. But when -gvn parameters is passed (in case 4) , why does the total number of strore Instruction present on the attached file increases (instead of decrease). Please explain...

Hi. Im exploring `opt -reg2mem` output for a simple C program (actually, that is this snippet: http://rosettacode.org/wiki/Dining_philosophers#C - compiled with clang -O1) and got two questions regarding this pass. 1. How would I tell which memory locations were introduced by the pass, and which memory locations were present in...

...of which for the first 3 cases am able to understand the variation on total number of store inst. But when -gvn parameters is passed (in case 4) , why does the total number of strore Instruction present on the attached file increases (instead of decrease). Please explain considering that use of -reg2mem pass is mandatory. eg. clang -emit-llvm bzip.c -c -o bzip1.bc 1. opt -load /home/honey/llvm/build/Debug+Asserts/lib/loadInstruction.so -storeInstruction < bzip1.bc output :- Total Store Instruction 3115 2. opt -reg2mem -load /home/honey/llvm/build/Debug+Asserts/lib/loadInstruction.s...

Hi, guys. I'm interested in using reg2mem pass but not sure about the concept of it. Can you let me know a reference about it, if any? Forgive my ignorance. -_-; Thanks, Seung J. Lee

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; } ------------...

Hi, all I want to instrument load/store operations in LLVM IR. And I find the LLVM IR generated with flag -o3 is much more efficient than -o0, so I try to instrument on these optimized LLVM IR, but, some load operations are changed to Phi loads. Then, I try the -reg2mem flag to remove these phi nodes. The problems are: 1) I use visitLoadInst to collect these load operations, and it seems I cannot reach these loads that are generated by reg2mem? What is the reason? 2) Is there any way to compile with -O3 but not generate phi nodes ? -- Best Regards! Eric Lew --...

Hello, I'm trying to apply the reg2mem pass on my bc file, but it somehow adds an instruction before a landingpad instruction and so I get a broken module error: The unwind destination does not have a landingpad instruction! %41 = invoke %class.x* @_ZN10xC2Ev(%class.x* %.reload19)...

On Fri, 2007-08-10 at 00:51 -0500, Seung Jae Lee wrote: > Hi, guys. > > I'm interested in using reg2mem pass but not sure about the concept of it. > Can you let me know a reference about it, if any? > Forgive my ignorance. -_-; The reg2mem pass undoes SSA form. That is, it turns SSA registers into alloca instructions with loads and stores. > > Thanks, > Seung J. Lee > __________...

...ely, when we >> run "opt -load LLVMPolly.so" for this basic LLVM IR code, the polly-prepare >> pass would introduce a large number of store instructions like this: >> >> define i32 @main(i32 %argc, i8** nocapture readonly %argv) { >> entry: >> %cond22.reg2mem = alloca i32 >> %x.019.reg2mem = alloca i32 >> %x.1.lcssa.reg2mem = alloca i32 >> %x.1.lcssa.lcssa.reg2mem = alloca i32 >> %x.0.lcssa.reg2mem = alloca i32 >> br label %entry.split >> entry.split: >> %cmp = icmp eq i32 %argc, 2 >> store i...

...wrote: > Hi, all > > I want to instrument load/store operations in LLVM IR. And I find the LLVM > IR generated with flag -o3 is much more efficient than -o0, so I try to > instrument on these optimized LLVM IR, but, some load operations are changed > to Phi loads. Then, I try the -reg2mem flag to remove these phi nodes. > The problems are: > 1) I use visitLoadInst to collect these load operations, and it seems I > cannot reach these loads that are generated by reg2mem? What is the reason? Clang doesn't generate optimized IR - so if your instrumentation is in Clang'...

On 31.8.2011, at 11.41, Eli Friedman wrote: > Mmm... reg2mem will transform IR with PHI's into IR without them, but > it generates a bunch of alloca's, which I would assume are not cheap > to lower to VHDL. You might have to write your own pass to get the > precise transformation you're looking for. Right. Thanks. I need to see the reg...

...on this code. Unfortunately, when we > run "opt -load LLVMPolly.so" for this basic LLVM IR code, the polly-prepare > pass would introduce a large number of store instructions like this: > > define i32 @main(i32 %argc, i8** nocapture readonly %argv) { > entry: > %cond22.reg2mem = alloca i32 > %x.019.reg2mem = alloca i32 > %x.1.lcssa.reg2mem = alloca i32 > %x.1.lcssa.lcssa.reg2mem = alloca i32 > %x.0.lcssa.reg2mem = alloca i32 > br label %entry.split > entry.split: > %cmp = icmp eq i32 %argc, 2 > store i32 46, i32* %cond22.reg2mem >...