similar to: [LLVMdev] where does %a_addr.0 come from?

Hi Maarten, If you look at the start of basic block 2 (bb2) you'll see the following instruction: %a_addr.0 = phi i32 [ 1, %bb ], [ 0, %bb1 ] ; <i32> [#uses=1] This is an SSA phi node which assigns a value of either 1 or 0 to %a_addr.0 depending on whether control reached the PHI node from basic block bb, or bb1. - Lang. On Thu, Sep 23, 2010 at 11:26 PM, maarten faddegon <

On Fri, Sep 21, 2012 at 3:08 PM, Welson Sun <welson.sun at gmail.com> wrote: > OK, with the restrict type qualifier, it is a little bit better: > > The IR's function signature becomes: > define void @foo(i32* noalias %a, i32* noalias %b, i32* noalias %c) nounwind > { > > Now the AA result: > Function: foo: 13 pointers, 0 call sites > NoAlias: i32* %a,

Here is the result of running mem2reg then basicaa, it is even worse: (%a should be alias to %0, and partial alias to %3) opt -mem2reg -basicaa -aa-eval -print-all-alias-modref-info < foo.s > /dev/null Function: foo: 6 pointers, 0 call sites NoAlias: i32* %a, i32* %b NoAlias: i32* %a, i32* %c NoAlias: i32* %b, i32* %c PartialAlias: i32* %1, i32* %a NoAlias:

Dear LLVM, I would like to understand how to improve the LLVM alias analysis accuracy. I am currently using llvmgcc 2.9 and llvm 3.0. Here is the C code: void foo(int a[SIZE], int b[SIZE], int c[SIZE]) { for(int i=0; i<SIZE; i++) c[i] = a[i] + b[i]; } Here is the IR: target datalayout =

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

---------- 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

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

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

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

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

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: >> >>

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 = add %x, 10 ... bb3: %phi = [bb1, %y], [bb2, %z] into define internal i32 @function(i32 %x) { ... bb1: ...

On Fri, Jun 28, 2019 at 3:35 PM James Y Knight <jyknight at google.com> wrote: > On Fri, Jun 28, 2019 at 5:53 PM Bill Wendling <isanbard at gmail.com> wrote: > >> On Fri, Jun 28, 2019 at 1:48 PM James Y Knight <jyknight at google.com> >> wrote: >> >>> On Fri, Jun 28, 2019 at 3:00 PM Bill Wendling <isanbard at gmail.com> >>> wrote:

On Mon, Jul 1, 2019 at 6:25 PM Finkel, Hal J. <hfinkel at anl.gov> wrote: > On 7/1/19 1:38 PM, Bill Wendling via llvm-dev wrote: > > On Fri, Jun 28, 2019 at 3:35 PM James Y Knight <jyknight at google.com> > wrote: > >> On Fri, Jun 28, 2019 at 5:53 PM Bill Wendling <isanbard at gmail.com> wrote: >> >>> On Fri, Jun 28, 2019 at 1:48 PM James Y

> Ok, suppose you have the following code: > BB1: > llvm.lifetime.start(%a) > store to %a > llvm.lifetime.end(%a) > br %BB2 > > BB2: > <some code> > br %BB1 > > If you remove the first "llvm.lifetime.start", then when you enter > %BB1 for the second time, your "store to %a" can be considered invalid, > as you've

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

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

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, is there a pass to get rid of phi-instructions in a function? There's no loop involved. I have a function approx. like this: void @func() { entry: … bb1: … bb2: … %tmp100 = phi i32 [ 0, bb1 ], [ 1, bb2 ] … %tmp101 = getelementptr …, %tmp100 tail call void @anotherfunc(…, %tmp101) ret void } I would like it to rather be something like this: void @func() { entry: … bb1: ...