similar to: [LLVMdev] Eliminating PHI with Identical Inputs

Hi John, On 30/07/13 16:12, John Criswell wrote: > Dear All, > > Is there a pass (or set of passes) that will replace a phi whose input operands > all compute the same value with an instruction that computes that value? In > other words, something that will convert: > > define internal i32 @function(i32 %x) { > ... > bb1: > %y = add %x, 10 > ... > bb2: > %z

On 7/30/13 9:46 AM, Duncan Sands wrote: > Hi John, > > On 30/07/13 16:12, John Criswell wrote: >> Dear All, >> >> Is there a pass (or set of passes) that will replace a phi whose >> input operands >> all compute the same value with an instruction that computes that >> value? In >> other words, something that will convert: >> >>

---------- Forwarded message ---------- From: Ryan Taylor <ryta1203 at gmail.com> Date: Mon, Feb 6, 2012 at 10:36 AM Subject: Re: [LLVMdev] Updating PHI for Instruction Domination? To: Eric Christopher <echristo at apple.com> Since I'm not sure which instructions I might want to replicate, would it be possible to cast the Value from "PHINode::getIncomingValue" to

I guess not since Value is a superclass of Instruction. On Mon, Feb 6, 2012 at 10:36 AM, Ryan Taylor <ryta1203 at gmail.com> wrote: > > > ---------- Forwarded message ---------- > From: Ryan Taylor <ryta1203 at gmail.com> > Date: Mon, Feb 6, 2012 at 10:36 AM > Subject: Re: [LLVMdev] Updating PHI for Instruction Domination? > To: Eric Christopher <echristo at

You're creating a new path that doesn't include L. For all values defined in L and used outside of L, you need to determine the new reaching def. That's specific to your transformation and can't be automated. Once you do that, creating the phi in F is natural. -Andy On Feb 6, 2012, at 11:51 AM, Ryan Taylor <ryta1203 at gmail.com> wrote: > I guess not since Value is a

On May 22, 2014, at 3:51 PM, Chandler Carruth <chandlerc at google.com> wrote: > > On Thu, May 22, 2014 at 4:42 PM, Louis Gerbarg <lgg at apple.com> wrote: > The problem that the above transform is technically illegal because “When indexing into a (optionally packed) structure, only i32 integer constants are allowed (when using a vector of indices they must all be the same

Hi all, We noticed a lot of unnecessary ptrtoint instructions that stand in way of some of our optimizations; the code pattern looks like this: bb1: %int1 = ptrtoint %struct.s* %ptr1 to i64 bb2: %int2 = ptrtoint %struct.s* %ptr2 to i64 %bb3: %phi.node = phi i64 [ %int1, %bb1 ], [%int2, %bb2 ] %ptr = inttoptr i64 %phi.node to %struct.s* In short, the pattern above arises due to: 1.

On 01/26/2011 07:50 PM, Vu Le wrote: > I guess I didn't have a clear question. > > Suppose we have BB1 and BB2 both point to BB3. > BB1 has variable x. BB2 also as variable x. > BB3 will have PHINode for x with 2 value from BB1 and BB2. > BB1 BB2 > \ / > BB3 > > Now if BB1 and BB2 is extracted into a function > (using ExtractCodeRegion), they

Dear all, I'm working on an exploratory backend on llvm. In the instruction set I'm using I have an instruction (called DECJNZ) that decrements a register and, if the decremented value is not zero, jumps (with a relative jump) to a given offset. I've described in tablegen this instruction as follow: def DECJNZ : Instruction { let Namespace = "MyTarget"; let

I guess I didn't have a clear question. Suppose we have BB1 and BB2 both point to BB3. BB1 has variable x. BB2 also as variable x. BB3 will have PHINode for x with 2 value from BB1 and BB2. BB1 BB2 \ / BB3 Now if BB1 and BB2 is extracted into a function (using ExtractCodeRegion), they will be replaced by a basic block called codeRepl (which has a call to the extracted

On Wed, Jul 25, 2012 at 12:48 AM, Michele Scandale <michele.scandale at gmail.com> wrote: > Dear all, > > I'm working on an exploratory backend on llvm. In the instruction set I'm using > I have an instruction (called DECJNZ) that decrements a register and, if the > decremented value is not zero, jumps (with a relative jump) to a given offset. > > I've

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

I want to do the following: suppose the program structure: bb / \ bb1 bb2 \ / bb3

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

Recently I posted a patch to migrate certain GEPs between basic blocks in cases where doing so would improve the ability of instcombine to merge into more complicated addressing mode (r209049 and r209065). After some build to failures it was rolled back. I now have a patch that no longer causes the regressions I was seeing, but it also no longer can optimize the case I was trying to optimize. As

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

On 02/25/2015 10:41 AM, Rafael Espíndola wrote: >>> all the zero paths from entry to %a pass by %b. >> >> That is a graph-wise definition, sure. >> So, this is an interesting definition, and maybe this is part of the source >> of the problem. >> >> For SSA, at least GCC requires that both "definition block dominates use >> block" (which

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 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

On Sun, Feb 5, 2017 at 3:41 PM, Nuno Lopes <nunoplopes at sapo.pt> wrote: > Thanks for the answers! The plan makes sense to me. > > Regarding phis, what about diamonds, e.g.: > > > define i32 @f(i32 %x) { > br .., label %bb0, label %bb1 > bb0: > %cmp = icmp sge i32 %x, 0 ; x > 0 > br i1 %cmp, label %bb2, label %bb3 > bb1: > %x2 = add nsw