similar to: [MemorySSA] A question about how to update the MemorySSA when we call RecursivelyDeleteTriviallyDeadInstructions

Hi guys, a question about updating memory SSA: Is it expected that e.g insertion of MemoryDef doesn't change all dominated uses? For example test case CreateLoadsAndStoreUpdater produces: define void @F(i8*) { ; 1 = MemoryDef(liveOnEntry) store i8 16, i8* %0 ; 4 = MemoryDef(1) store i8 16, i8* %0 br i1 true, label %2, label %3 ; <label>:2: ;

In particular, if you want to add support, the right way to know what to rename is (off the top of my head) add a flag or something to have renamepass reset all uses it sees (you only have to change the uses, defs are all linked together and thus already fixed by the updater). Right now it only does that if they have no defining access. Make it skip blocks already in the visited set (the

I understand that changing the starting element to “InsertedPHIs.being() + StartingPHISize” it will be finite but given that InsrtedPHIs is finite. I have a case where one element(same element is appened to InsertedPHIs) is added to InsertedPHIs every time fixupDefs is invoked. I traced the issue why this was happening. template <class RangeType> MemoryAccess

We should only add phis that were newly inserted, not ones that were already found. There are two cases we will hvae inserted phis: Part of the recursive call, or right in this function. The easiest way to differentiate new phis from old ones is whether they have 0 operands. I expect the attached will fix it. If not, please file a bug with reproducible IR. On Sun, Sep 24, 2017 at 11:40 PM,

With regards Bhargav Reddy Godala Software Engineer 2 Bangalore, India E-mail: Bhargav-reddy.Godala at amd.com<mailto:Bhargav-reddy.Godala at amd.com> Ext 30678 On 23-Sep-2017, at 9:27 PM, Daniel Berlin <dberlin at dberlin.org<mailto:dberlin at dberlin.org>> wrote: On Sat, Sep 23, 2017 at 8:38 AM, Godala, Bhargav-reddy via llvm-dev <llvm-dev at

On Sat, Sep 23, 2017 at 9:55 AM, Godala, Bhargav-reddy < Bhargav-reddy.Godala at amd.com> wrote: > > With regards > Bhargav Reddy Godala > Software Engineer 2 > Bangalore, India > E-mail: Bhargav-reddy.Godala at amd.com Ext 30678 > > > > On 23-Sep-2017, at 9:27 PM, Daniel Berlin <dberlin at dberlin.org> wrote: > > > > On Sat, Sep 23, 2017 at

Hi All, I'm looking into converting LICM to use MemorySSA instead of AliasSets to determine when it is safe to hoist/sink/promote loads and stores to get around the issue of alias set collapse (see discussion [1]). I have a prototype implementation, but have run into two issues that I could use input from the designers of MemorySSA to resolve: 1) Is MemorySSA intended to be

Hello all, It seems that it is insufficient to rely on MemorySSA to correctly reorder load/stores. For example, we have this following code: v = load q store 10, p => store 10, p v = load q // This is incorrect if p and q may alias In the MemorySSA representation however, there's no syntactic dependency between load/store, because MemorySSA before transformation would look like this:

Can you share you compile-time and memory footprint measurements at least for CTMark? For a new pass/feature it would be great to share this with the community before you commit. Or did I miss them? Thanks Gerolf > On Jun 27, 2017, at 3:26 PM, Geoff Berry via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > EarlyCSE w/ MemorySSA has been enabled by default as of r306477 >

Hi All, I'd like to switch the function simplification run of EarlyCSE to use MemorySSA by default. This change has been in tree for a while and I've done benchmark and self-hosting testing on both aarch64 and x86, but I wanted to give other folks with different tests/targets a chance to try this out before I flip the switch. I've added an option

Hi Daniel, Thanks for the info. I’ve started looking into converting EarlyCSE to use MemorySSA first since 1) I don’t think it needs any additional MemorySSA update API and 2) the particular case I’m looking at needs EarlyCSE to catch more load cases before LICM to be profitable. I have a prototype working, but have run into two issues: 1) readonly calls are treated as clobbers by

Hi, I am new to MemorySSA and wanted to understand its capabilities. Hence I wrote the following program (test.c): int N; void test(int *restrict a, int *restrict b, int *restrict c, int *restrict d, int *restrict e) { int i; for (i = 0; i < N; i = i + 5) { a[i] = b[i] + c[i]; } for (i = 0; i < N - 5; i = i + 5) { e[i] = a[i] * d[i]; } } I compiled this program using

+1 If possible, it definitely helps to fuzz it. On Sat, Jun 10, 2017 at 2:45 PM, Davide Italiano via llvm-dev < llvm-dev at lists.llvm.org> wrote: > On Sat, Jun 10, 2017 at 8:21 AM, Geoff Berry via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > Hi All, > > > > I'd like to switch the function simplification run of EarlyCSE to use > > MemorySSA by

Hi, I have a question about how llvm MemorySSA works, as seems I misunderstand something. Consider following code snippet and corresponding IR with MemorySSA annotations (got with opt -print-memoryssa) void foo(int* b) { int a = 0; int d = 12; if (b) { a = 42; d = 32; } int c = a; int e = d; } ; Function Attrs: noinline nounwind optnone uwtable

On Tue, Dec 19, 2017 at 9:10 AM, Siddharth Bhat via llvm-dev < llvm-dev at lists.llvm.org> wrote: > I could be entirely wrong, but from my understanding of memorySSA, each > def defines an "abstract heap state" which has the coarsest possible > definition - any write will be modelled as a "new heap state". > This is true for def-def relationships, but

Hi, try adding some alias analysis to the pipeline: see examples in llvm/test/Analysis/MemorySSA/*.ll for example assume.ll has ; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>,verify<memoryssa>' without basic-aa the memory ssa will safely assume that the stores to %a and %d alias which may be proven disjoint by one of the alias analyses. On Thu, Aug 9, 2018 at 8:37

Hey All, I've come across what I believe to be a bug in MemorySSA. George, I wasn't sure if this was a known issue that you'll be addressing in your upcoming walker caching changes or not, so I haven't investigated it very much. The test case is attached. The bug is that the defining access for the second load is set to the loop MemoryPhi node instead of being liveOnEntry as

Hi, Can some one explain the intended behaviour of following loop in void MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) function. while (!FixupList.empty()) { unsigned StartingPHISize = InsertedPHIs.size(); fixupDefs(FixupList); FixupList.clear(); // Put any new phis on the fixup list, and process them FixupList.append(InsertedPHIs.end() - StartingPHISize,

On Sat, Sep 23, 2017 at 8:38 AM, Godala, Bhargav-reddy via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi, > > Can some one explain the intended behaviour of following loop in void > MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) function. > > while (!FixupList.empty()) { > unsigned StartingPHISize = InsertedPHIs.size(); >

This is definitely a caching bug related to this code: 1038 // Don't try to optimize this phi again if we've already tried to do so. 1039 if (!Q.Visited.insert(PHIPair).second) { 1040 ModifyingAccess = CurrAccess; 1041 break; 1042 } We don't differentiate elsewhere between having stopped at a phi because we were path walking and discovered that path