search for: earlyclobber

Hi Quentin, > It sounds like you only need the earlyclobber description for the N, N > variant. > In other words, as long as you use different opcodes for widen-op NN and > widen-op WN, you model exactly what you want. > > What am I missing? > we are using different opcodes for widen-op NN and widen-op WN. My understanding is that not se...

Hello, I'm getting a machine verifier error after introducing the earlyclobber constraint to some instructions where the src and dest regs can't be the same. The offending instruction pattern is this one: let canFoldAsLoad = 1, isReMaterializable = 1, Constraints = "@earlyclobber $dst" in def LDDWRdPtrQ : Inst<(outs DREGS:$dst), (ins...

On Jul 14, 2012, at 10:09 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: > Hello, > > I'm getting a machine verifier error after introducing the earlyclobber constraint to some instructions where the src and dest regs can't be the same. The offending instruction pattern is this one: > > let canFoldAsLoad = 1, > isReMaterializable = 1, > Constraints = "@earlyclobber $dst" in > def LDDWRdPtrQ : Inst<(outs DREGS:$dst), >...

...ill include them. Thanks for your help! 2012/7/14 Jakob Stoklund Olesen <stoklund at 2pi.dk> > > On Jul 14, 2012, at 10:09 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: > > > Hello, > > > > I'm getting a machine verifier error after introducing the earlyclobber > constraint to some instructions where the src and dest regs can't be the > same. The offending instruction pattern is this one: > > > > let canFoldAsLoad = 1, > > isReMaterializable = 1, > > Constraints = "@earlyclobber $dst" in > > def LDDWRdPtrQ...

...ly, an input of a different kind (W vs N). For instance: W1 = widen-op N4, N5 [this is ok, W1 is (N2, N3), so no overlap] W1 = widen-op N3, N4 [this is wrong because W1 is (N2, N3), thus overlap] W1 = widen-op W1, N4 [this is OK, W1 does not overlap with N4] I can model these constraints using @earlyclobber and it works great for the `Wdest = widen-op Nsrc1, Nsrc2` case. While correct, this is suboptimal for the `Wdest = widen-op Wsrc1, Nsrc2` case because RA will never assign registers as in: W1 = widen-op W1, N4 [RegAlloc would do something like W3 = widen-op W1, N4] Has anyone encountered a simil...

...gt; > > 2012/7/14 Jakob Stoklund Olesen <stoklund at 2pi.dk> > >> >> On Jul 14, 2012, at 10:09 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: >> >> > Hello, >> > >> > I'm getting a machine verifier error after introducing the earlyclobber >> constraint to some instructions where the src and dest regs can't be the >> same. The offending instruction pattern is this one: >> > >> > let canFoldAsLoad = 1, >> > isReMaterializable = 1, >> > Constraints = "@earlyclobber $dst" in...

...on ldw r1:r2, P to load 2 bytes from memory address P is to be expaneded to ld r1, P+ ld r2, P where "ld _, P+" is an instruction that loads a single byte from P, and post-increments P by one. How can I represent this behaviour in LLVM? Currently, I have let Constraints = "@earlyclobber $reg" in def LDWRdPtr : Pseudo<(outs DREGS:$reg), (ins PTRREGS:$ptrreg), "ldw\t$reg, $ptrreg", [(set i16:$reg, (load i16:$ptrreg))]>, Requires<[HasSRAM]>; The problem, of cour...

...; Do you have specific examples in mind that would be expressible with > something more complicated that aren't handleable via an early-clobber > constraint? Not offhand, no. I'm mostly concerned about the readability of .td files. > Perhaps spelling it out more fully with "earlyclobber" rather than > "early" would help? That's better. Is there any way you could convince TableGen to recognize that 'constraints = "$success != $src", "$success != $ptr"' is semantically equivalent to earlyclobber? Maybe check that the common operan...

...operand > > This seems more intuitive and more generally applicable. I could > see a use > for this in other architectures. From reading your example, without > the > background I wouldn't know what "@early" means. Perhaps spelling it out more fully with "earlyclobber" rather than "early" would help? Thanks for the feedback! -Jim -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20091215/b5ad25f8/attachment.html>

...9;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 InlineSpiller::foldMemoryOperand() returns true, so a very wild guess is that maybe when calling LIS.ReplaceMachineInstrInMaps() the new SlotIndex created is not of type Slot_EarlyClobber since the MI being replaced is a COPY with no EC ops. I've also found a way for you to reproduce this error in a simple way with the ARM backend with -march=thumb: Just add "Constraints = "@earlyclobber $Rt" in" to the tLDRspi instruction in ARMInstrThumb.td (around line 62...

On Jul 15, 2012, at 9:20 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: > Jakob, one more hint, I've placed some asserts around the code you added and noticed that the InlineSpiller::insertReload() function is not being called. > > 2012/7/14 Borja Ferrer <borja.ferav at gmail.com> > Hello Jakob, > > I'm still getting the error, I can give you any other

Hi, How can I specify in a .td file that source and destination should not use the same register? Thanks. - Elena --------------------------------------------------------------------- Intel Israel (74) Limited This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If

Hi Kevin, I concur Tim’s advice, you should use the @earlyclobber. Cheers, -Quentin On Feb 19, 2014, at 3:27 AM, Tim Northover <t.p.northover at gmail.com> wrote: > Hi Kevin, > >> I suppose to add some extra rules on register allocator to avoid it >> allocating register causing any unpredictable behavior, but I don't have >>...

...t would be expressible with >> something more complicated that aren't handleable via an early- >> clobber >> constraint? > > Not offhand, no. I'm mostly concerned about the readability of .td > files. > >> Perhaps spelling it out more fully with "earlyclobber" rather than >> "early" would help? > > That's better. Is there any way you could convince TableGen to > recognize > that 'constraints = "$success != $src", "$success != $ptr"' is > semantically > equivalent to earlyclobber...

...9;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 InlineSpiller::foldMemoryOperand() returns true, so a very wild guess is that maybe when calling LIS.ReplaceMachineInstrInMaps() the new SlotIndex created is not of type Slot_EarlyClobber since the MI being replaced is a COPY with no EC ops. OK, I see what is happening. We don't expect foldMemoryOperand to turn a normal def into an early-clobber and vice versa. This is not easy to fix, could you file a PR, please? As a workaround, you can use a pseudo-instruction in loadRegFr...

Hi, To fix this bug(http://llvm.org/bugs/show_bug.cgi?id=18881), we need to add more register constraints that for STLXR , Ws and Wt should not be the same register. Because these unpredictable instructions are valid instructions in MC layer, we couldn't just simply treat them as unallocated encoding. I suppose to add some extra rules on register allocator to avoid it allocating register

On Sun, 28 May 2017, David Chisnall wrote: >> let Constraints = "@earlyclobber $reg" in >> def LDWRdPtr : Pseudo<(outs DREGS:$reg), >> (ins PTRREGS:$ptrreg), >> "ldw\t$reg, $ptrreg", >> [(set i16:$reg, (load i16:$ptrreg))]>, >> Requires<[...

One other minor thing: I notice that in the inline assembly the result (rd) is constrained as an earlyclobber operand. What was the reason for that?

Is there a way to force the register allocator to avoid reusing an operand register for a definition? For example, the following machine instruction reuses a register for the first operand and definition: %uI7<def> = eq at III %uI7<kill>, %uI4 I'd like: %uI8<def> = eq at III %uI7<kill>, %uI4 I'm guessing that the right way to do this would be to kill the

Hello, > I'm guessing that the right way to do this would be to kill the operand > registers after the given machine instruction rather than before it, but > I don't see a way to mark it this way. Right now the only way is to mark output reg as earlyclobber (see ARM backend for examples). Note that post-RA scheduler is not yet aware about earlyclobber operands and thus can break the constraint. -- With best regards, Anton Korobeynikov Faculty of Mathematics and Mechanics, Saint Petersburg State University