similar to: [LLVMdev] Inneffiecient code produced by reg2mem?

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

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 searched all passes under

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

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 the original program? After a brief diffing of .ll files, I'd

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

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

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.

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) to label %.noexc unwind label %88

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

Best Regards! Eric Lew On 周三, 4月 22, 2015 at 12:11 下午, David Blaikie < dblaikie at gmail.com [dblaikie at gmail.com] > wrote: On Tue, Apr 21, 2015 at 8:34 PM, Eric Lu <eirc.lew at gmail.com> 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 >

Hi Preston, On Fri, May 4, 2012 at 9:12 AM, Preston Briggs <preston.briggs at gmail.com> wrote: > > which produces > > %arrayidx24 = getelementptr inbounds [100 x [100 x i64]]* %A, i64 > %arrayidx21.sum, i64 %add1411, i64 %add > store i64 0, i64* %arrayidx24, align 8 > {{{(5 + ((3 + %n) * %n)),+,(2 * %n * %n)}<%for.cond1.preheader>,+,(4 *

Is there any chance of replacing/extending the GEP instruction? As noted in the GEP FAQ, GEPs don't support variable-length arrays; when the front ends have to support VLAs, they linearize the subscript expressions, throwing away information. The FAQ suggests that folks interested in writing an analysis that understands array indices (I'm thinking of dependence analysis) should be

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

Hi all, suppose there is a vector y with rownames: > y cond1 cond2 cond3 cond4 78.952 87.308 86.490 74.040 how can I easily plot this vector using the rownames? plot(y) gives me a plot with a x-axis from 1 to 4 in 0.5 steps, also plot(rownames(y), y) and plot(y ~ rownames(y) don't work. I know I can build a x-axis with axis(1, ...), but in this case I need a character string like

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 considering that use of -reg2mem pass is mandatory. eg. clang -emit-llvm bzip.c -c -o bzip1.bc

Hi everyone, I'm having some trouble with my ifelse statements. I'm trying to put 12 conditions within 3 groups. Here is the code I have so far: dat$cond <- ifelse(test = dat$cond == "cond1" | dat$cond == "cond2" | dat$cond == "cond3" dat$cond == "cond4" yes = "Uniform" no = ifelse(test =

Not a reproducible example, so a bit of guessing here, but a) don't try to assign results to variables inside the ifelse. That is, remove all the single-equals signs and "test" variables. If you really need to conditionally assign variables then use "if"... but chances are good you don't need that. b) "closure" is effectively another word

I have a register allocation bug I'm trying to track down. It's caused by a convoluted series of events that results in a massive amount of code, so looking at asm diffs is rather unhelpful. I came up with the bright idea of adding a MaxPromotes flag to limit the number of candidates that mem2reg promotes. But I couldn't figure out how to safely promote some candidates but not

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 ] ;

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 ; <i32>