similar to: [LLVMdev] Possible missed optimization?

Hello Jakob, thanks for the reply. The three regclasses involved here are all subsets from each other and aren't disjoint. These are the basic descriptions of the regclasses involved to show what i mean: DREGS: R31R30, R29R28 down to R1R0 (16 regs) DLDREGS: R31R30, R29R28 down to R17R16 (8 regs) PTRREGS: R31R30, R29R28, R27R26 (3 regs) All classes intersect each other

On Mar 24, 2011, at 5:42 PM, Borja Ferrer wrote: > The last copy instruction should be removed as pointed out above, but since R27R26 is killed in the load instruction it has to be emitted. About the insane amount of regclasses there, the load/store and the andi instructions take subsets of regs from the main register class, they cant work with all registers, that's why STW and LDW needs

On Mar 26, 2011, at 4:09 PM, Borja Ferrer wrote: > You can look at the output of -debug-only=regcoalescing to see what is going on. > > This is the debug output i've got, some information is a bit cryptic for me so next is what i understood: > > ********** SIMPLE REGISTER COALESCING ********** > ********** Function: foo > ********** JOINING INTERVALS *********** >

> > You can look at the output of -debug-only=regcoalescing to see what is > going on. > > This is the debug output i've got, some information is a bit cryptic for me so next is what i understood: ********** SIMPLE REGISTER COALESCING ********** ********** Function: foo ********** JOINING INTERVALS *********** entry: 16L %vreg0<def> = COPY %R25R24<kill>;

On Mar 26, 2011, at 1:04 PM, Borja Ferrer wrote: > Hello Jakob, thanks for the reply. The three regclasses involved here are all subsets from each other and aren't disjoint. These are the basic descriptions of the regclasses involved to show what i mean: > > DREGS: R31R30, R29R28 down to R1R0 (16 regs) > DLDREGS: R31R30, R29R28 down to R17R16 (8 regs) > PTRREGS:

Hello, I noticed the following interesting code sequence while compiling a piece of code with the backend I'm developing. Probably this issue is for Jakob, but anyways this is what I'm getting: STDWPtrQRr <fi#12>, 0, %R25R24; mem:ST2[FixedStack12](align=1) STDWPtrQRr <fi#12>, 0, %R25R24; mem:ST2[FixedStack12](align=1) STDWPtrQRr <fi#13>, 0, %R23R22;

On Jan 27, 2012, at 10:20 AM, Borja Ferrer wrote: > Hello, > > I noticed the following interesting code sequence while compiling a piece of code with the backend I'm developing. Probably this issue is for Jakob, but anyways this is what I'm getting: > > STDWPtrQRr <fi#12>, 0, %R25R24; mem:ST2[FixedStack12](align=1) > STDWPtrQRr <fi#12>, 0, %R25R24;

On Apr 26, 2011, at 1:27 PM, Borja Ferrer wrote: > Hello Jim thanks for the reply, > > For normal additions with immediates I've done the same as ARM does, basically transforming add(x, imm) nodes to sub(x, -imm) with a pattern in the .td file like this: > def : Pat<(add DLDREGS:$src1, imm:$src2), > (SUBIWRdK DLDREGS:$src1, (imm16_neg_XFORM imm:$src2))>;

Thanks Jim, I've implemented the negation part successfully :) maybe the second part could be a possible feature request so others could use it aswell? 2011/4/27 Jim Grosbach <grosbach at apple.com> > > On Apr 26, 2011, at 1:27 PM, Borja Ferrer wrote: > > > Hello Jim thanks for the reply, > > > > For normal additions with immediates I've done the same as

Hello Jim thanks for the reply, For normal additions with immediates I've done the same as ARM does, basically transforming add(x, imm) nodes to sub(x, -imm) with a pattern in the .td file like this: def : Pat<(add DLDREGS:$src1, imm:$src2), (SUBIWRdK DLDREGS:$src1, (imm16_neg_XFORM imm:$src2))>; Now, the typical pattern concerning additions with global addresses looks

I'm attempting to implement codegen support for the AVR ST/LD <http://www.atmel.com/webdoc/avrassembler/avrassembler.wb_ST.html> family of instructions. The binary encoding is not particularly consistent -- take a look at this table of variants of LD, along with their machine code representation: # load 8 bits from pointer register X into general purpose Rd ld Rd, X `1001 000d dddd

Jakob I've just noticed that I'm getting false positives about spills when there are actually none. What is happening is that although execution reaches to the line spiller().spill(LRE); inside RAGreedy::selectOrSplit() the insertion of the spill is avoided because the register gets rematted. This is the debug output I'm getting to show what I mean: Inline spilling

On Dec 8, 2011, at 12:15 PM, Borja Ferrer wrote: > Jakob I've just noticed that I'm getting false positives about spills when there are actually none. > What is happening is that although execution reaches to the line spiller().spill(LRE); inside RAGreedy::selectOrSplit() the insertion of the spill is avoided because the register gets rematted. This is the debug output I'm

Hello, some months ago i wrote to the mailing list asking some questions about register pairing, i've been experimenting several things with the help i got back then. Some background first: this issue is for a backend for an 8bit microcontroller with only 8bit regs, however it has a few 16bit instructions that only work with fixed register pairs, so it doesnt allow all combinations of regs.

Hi, During instruction selection, I have the following code for certain LOAD instructions: const LoadSDNode *LD = cast<LoadSDNode>(N); SDNode* LDW = CurDAG->getMachineNode(AVR::LDWRdPtr, SDLoc(N), VT, PtrVT, MVT::Other, LD->getBasePtr(), LD->getChain()); // Honestly, I have no idea what this does, but other memory // accessing instructions

On Nov 27, 2010, at 8:56 AM, Borja Ferrer wrote: > Some background first: this issue is for a backend for an 8bit microcontroller with only 8bit regs, however it has a few 16bit instructions that only work with fixed register pairs, so it doesnt allow all combinations of regs. This introduces some problems because if data wider than 8bits is expanded into 8bit operations the 16bit instructions

Hi, I'd like to define a pseudo-instruction whose expansion will, as a side-effect, overwrite an input register's value: the pseudo-instruction 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

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))]>, >>

Hello, On Apr 26, 2011, at 6:30 AM, Borja Ferrer wrote: > Hello, I have some questions regarding folding operations with symbols during the instruction print stage with MC. At the moment I'm working with global symbols but i guess that other symbol types should be equivalent. > > My first question is how can i negate the address of a symbol? > > Consider this piece of code:

Hello, I have some questions regarding folding operations with symbols during the instruction print stage with MC. At the moment I'm working with global symbols but i guess that other symbol types should be equivalent. My first question is how can i negate the address of a symbol? Consider this piece of code: char g_var[80]; char foo(int a) { return g_var[a]; } this gets compiles into