similar to: Understanding SlotIndexes

On 12/22/2016 4:02 PM, via llvm-dev wrote: > > /// Early-clobber register use/def slot. A live range defined at > /// Slot_EarlyCLobber interferes with normal live ranges killed at > /// Slot_Register. Also used as the kill slot for live ranges tied to an > /// early-clobber def. > Slot_EarlyClobber, > > What does this mean, exactly? My

Hi Jonas, Thanks for your patience. After spending some time looking at the additional output you gave me, I agree that your fix is the right one. I was worried that this problem may arise because we were spilling not real user, but in fact what I thought was the problem is an optimization we could do :). See my comments inlined for a few nitpicks before you commit. Thanks again, -Quentin On

Jakob Stoklund Olesen <stoklund at 2pi.dk> writes: >> Are all of those sibling values guaranteed to ultimately derive from the >> same def, in the sense that they can be traced through copies, phis, >> etc. back to a single instruction? > > They are known the all come from the same value in the original live range from before live range splitting. Ok, that's

Hello LLVM Developers, We are working on extending currently available register rematerialization to include cases where sequence of multiple instructions is required to rematerialize a value. We had a discussion on this in community mailing list and link is here: http://lists.llvm.org/pipermail/llvm-dev/2016-September/subject.html#104777 >From the above discussion and studying the code we

Hi Quentin, I have tried to find a test case for an official target, but failed. It seems to be a rare case. To do it, I added the 'else' clause in the following: ... if (VNI->def == OrigVNI->def) { DEBUG(dbgs() << "orig phi value\n"); SVI->second.DefByOrigPHI = true; SVI->second.AllDefsAreReloads = false; propagateSiblingValue(SVI); continue;

Hi Quentin, I have rerun the test case on a recent commit, so the numbers have changed. There are also now a few more basic blocks very small basic blocks in the function, and therefore there are some slight differences. I tried to go back to earlier commits, without success for some reason... This is however very similar, except that there becomes two COPYs back to sibling value after the loop.

Hi, I have encountered a test case where InlineSpiller generates bad code. A register is reloaded but never spilled, and I suspect a bug in InlineSpiller. A register is live over a loop that also have two inner loops. It is not used or defined over the inner loops. It is split into two sibling registers, where one covers just the inner loops interval, which is then spilled. In spill(),

I've hit a bug in a refactored version of coalescing and I'm trying to understand what is going on. In particular, I'm curious about this line in SimpleRegisterCoalescing.cpp: 00710 LHSValsDefinedFromRHS[VNI] = RHS.getLiveRangeContaining(VNI->def-1)->valno; Why VNI->def-1? The bug I'm seeing is that RHS returns a NULL LiveRange because it doesn't contain

On Tuesday 25 September 2007 10:49, David Greene wrote: > I've hit a bug in a refactored version of coalescing and I'm trying to > understand what is going on. In particular, I'm curious about this > line in SimpleRegisterCoalescing.cpp: > > 00710 LHSValsDefinedFromRHS[VNI] = > RHS.getLiveRangeContaining(VNI->def-1)->valno; > > Why VNI->def-1?

When compiling trunk using gcc 4.1.2 on linux/ppc64, I now see a warning that I don't remember seeing previously: llvm[2]: Compiling InlineSpiller.cpp for Release+Asserts build /src/llvm-trunk-dev/include/llvm/ADT/PointerIntPair.h: In member function ‘const PointerTy* llvm::PointerIntPair<PointerTy, IntBits, IntType, PtrTraits>::getAddrOfPointer() const [with PointerTy = void*, unsigned

LLVM is assuming this: struct InstrSlots { enum { LOAD = 0, USE = 1, DEF = 2, STORE = 3, NUM = 4 }; So VNI->def is always modulo 2. For coalescing, it's checking if the RHS is live at the "use" cycle. So it's checking VNI->def-1. Evan On Sep 25, 2007, at 8:55 AM, David Greene wrote: > On Tuesday

On Thursday 17 January 2008 13:03, Evan Cheng wrote: > > So why does the live range extend throughout the entire basic block? > > > > %reg1055 doesn't appear anywhere else in the program so it shouldn't > > be > > live-in to the block. > > It could be a bug. Can you get me a test case? I'll see if I can whittle it down. It's a pretty huge

I just ran into a problem here. I'm in SimpleRegisterCoalescing at the point where EXTRACT_SUBREG coalescing updates live ranges of aliased registers (around line 473 of SimpleRegisterCoalescing.cpp). There's a call to MergeValueInAsValue at line 50. MergeValueInAsValue has this code: void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS,

On Tuesday 25 September 2007 12:25, Evan Cheng wrote: > LLVM is assuming this: > struct InstrSlots { > enum { > LOAD = 0, > USE = 1, > DEF = 2, > STORE = 3, > NUM = 4 > }; > > So VNI->def is always modulo 2. For coalescing, it's checking if the > RHS is live at the "use"

On Tuesday 25 September 2007 13:28, David Greene wrote: > > So VNI->def is always modulo 2. For coalescing, it's checking if the > > RHS is live at the "use" cycle. So it's checking VNI->def-1. > > But why is it looking at a use slot in this case, where the coalescer is > trying to get the vaue number for the def of the RHS register so it can > use

Hi, It looks like LiveIntervals::addIntervalsForSpills does not update all of the LiveIntervals infos quite correctly. In particular, if a live interval L is defined by Reg<-Reg copy instructions whose srcReg is later spilled by the addIntervalsForSpills() function, its VNInfo information is not updated in a proper way. It still points to the same MachineInstr as before, even though the

I think I'm getting a bit closer to the problem. I've found that the call to InlineSpiller::foldMemoryOperand() inside InlineSpiller::spillAroundUses() is causing the problems. As a test, I removed that call and with your yesterday's patch I'm not getting any errors at all, the code generated is the same one as with the call. This is happening when

On Aug 8, 2010, at 9:20 PM, Reid Kleckner wrote: > I thought I dug into the register allocation code, and found the > VNInfo::Allocator typedef. I assumed that was getting the traffic we > saw in Instruments, but I don't have the data to back that up. Are you using llvm from trunk? VNInfo is a lot smaller now than it was in 2.7. I would guess about a third of the liveness memory

On Sun, Aug 8, 2010 at 8:20 PM, Jakob Stoklund Olesen <stoklund at 2pi.dk> wrote: > > On Aug 7, 2010, at 7:05 PM, Steven Noonan wrote: >> I've been doing work on memory reduction in Unladen Swallow, and >> during testing, LiveRanges seemed to be consuming one of the largest >> chunks of memory. > > That's interesting. How did you measure this? I'd

On Jan 16, 2008, at 11:49 AM, David Greene wrote: > I had been assuming that give a LiveRange a, a.valno->def, if > valid, would be the same as a.start. But this is apparently not > always the case. For example: > > Predecessors according to CFG: 0x839d130 (#3) 0x8462780 (#35) > 308 %reg1051 = MOV64rr %reg1227<kill> > 312 %reg1052 = MOV64rr %reg1228<kill>