similar to: [LLVMdev] FW: Integer promotion of return node operand

On May 12, 2008, at 8:21 AM, Sachin.Punyani at microchip.com wrote: > > When LLVM constructs the DAG for above case - it tries to promote > (during DAG construction phase - before any combine or legalize phase) > the return node operand to i32. > > I have few doubts here: > 1) If C language requires integer promotion of return value argument > then should it not be done by

Hi All, Please consider the following case Test case -- -------------------------------------- char a; void fun () { return a; } -------------------------------------- Following disassembly (using llvm-dis) is generated for the above test case -------------------------------------- ; ModuleID = 'first.bc' @a = internal global i8 0 ; <i8*> [#uses=1] define i8 @fun(...) { entry:

On May 14, 2008, at 10:43 AM, Alireza.Moshtaghi at microchip.com wrote: > In this thread I’m trying to merge two email threads into one, > because both discuss the same problem that’s troubling us and I > would like to reach a conclusion on what would be the best approach. > To minimize the size of this thread I only mention the subject of > the other two threads: > (1)

On May 14, 2008, at 10:43 AM, <Alireza.Moshtaghi at microchip.com> <Alireza.Moshtaghi at microchip.com > wrote: > In this thread I’m trying to merge two email threads into one, > because both discuss the same problem that’s troubling us and I > would like to reach a conclusion on what would be the best approach. > To minimize the size of this thread I only mention

In this thread I'm trying to merge two email threads into one, because both discuss the same problem that's troubling us and I would like to reach a conclusion on what would be the best approach. To minimize the size of this thread I only mention the subject of the other two threads: (1) [LLVMdev] Integer promotion of return node operand (initiated by Sachin) (2) [LLVMdev] trouble

I know that many ABIs require this for performance purpose, but I haven't seen anything in the standard that suggests promotion of return value to integer. Furthermore, I think the LLVM is supposed to be independent of language. So I'm not sure if SelectionDAGLowering is the right place for this promotion to begin with, TargetLowering class seems more logical; but I'm not sure how.

Hi Sachin, Yes. Bernhard Scholz and I have just discussed a fix for this. I hope to commit it in the next few days. I will let you know as soon as it goes in to the mainline. Regards, Lang. On Tue, Dec 15, 2009 at 5:34 PM, <Sachin.Punyani at microchip.com> wrote: > Hi Lang, > > Thanks for your inputs on the problem. I was just curious to know if you > got any opportunity to

Thanks Lang! I think we can use linear scan as work around for short term. Thanks for your help. Regards Sachin > -----Original Message----- > From: Lang Hames [mailto:lhames at gmail.com] > Sent: Sunday, November 15, 2009 10:08 AM > To: Sachin Punyani - I00202 > Cc: llvmdev at cs.uiuc.edu > Subject: Re: [LLVMdev] Crash in PBQP register allocator > > Hi Sachin, >

Hi Lang, Thanks for your inputs on the problem. I was just curious to know if you got any opportunity to work on the solution for this. Regards Sachin > -----Original Message----- > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On > Behalf Of Sachin.Punyani at microchip.com > Sent: Tuesday, November 17, 2009 12:00 PM > Subject: Re: [LLVMdev] Crash

There is a FIXME part in SelectionDAGLowering::visitRet() that is giving us trouble. And I would like to know how the community has planned for addressing this problem. The current implementation assumes that all C calling conventions require the return value of integer types in the largest register class (for most ports 32-bit). However, this is not the case for our port. We have two register

Hi Sachin, llvm-dev, I've just committed a new PBQP solver which, among other things, should take care of this bug. Please let me know how it works out for you. Cheers, Lang. On Tue, Dec 15, 2009 at 5:54 PM, Lang Hames <lhames at gmail.com> wrote: > Hi Sachin, > > Yes. Bernhard Scholz and I have just discussed a fix for this. I hope to > commit it in the next few days. I

Hi Lang, I'm surprised about the fact that you omit R1/R2 reductions in some cases. Can you give a more detailed description of the bug (e.g. a PBQP dump)? Best regards, Sebastian Lang Hames wrote: > Hi Sachin, llvm-dev, > > I've just committed a new PBQP solver which, among other things, > should take care of this bug. > > Please let me know how it works out for you.

The driver behaves differently when I run it by specifying absolute path than when I run it with relative path. See example Relative: i00202 at ubuntu:/tmp$ mcc16 --save-temps -dry-run hello.c./clang-cc -I ./include -triple=pic16- -emit-llvm-bc hello.c -o hello.bc-pqDR1Y llvm-ld -link-as-library hello.bc-pqDR1Y -o tmp.bc-M1Rwip llc -march=pic16 -f tmp.bc-M1Rwip -o tmp.s-DcVczP gpasm -I ./inc

> BTW, Chris's Makefile changes broke llvmc yesterday (r75379). I'm > working on a fix. Hi Mikhail, Did you get a chance to fix this. I still get errors while building examples. i00202 at ubuntu:~/projects/llvm/tools/llvmc/example/mcc16$ make make[1]: Entering directory `/home/i00202/projects/llvm/tools/llvmc/example/mcc16/plugins' make[2]: Entering directory

I found out the problem. Looks like I can not rely on argv[0] to contain the full path of the executable always. Can I rely on: static Path GetMainExecutable(const char *argv0, void *MainAddr); is it Cross-platform? What to pass for second parameter here. C++ forbids taking address of "main", and the "Main" of CompilerDriver is in a shared object here. - Sanjiv Sanjiv

Hi Sachin, Confirmed: This is being caused by a subtle issue in the heuristic PBQP solver. Specifically: R1/R2 reductions as currently implemented can, on rare occasions, lead to the heuristic solver failing to find a finite cost solution, even though one exists. The infinite cost solution will always be in violation of some rule of register allocation (failing to handle an interference, or

Hi Evan, > If you are using a non-C ABI, then you may not need to do the > promotion at all. However, if you do need to do the promotion, you > need to know the type of "int". how does this work for parameters. Suppose I have an i1 parameter. The AMD64 ABI says it is passed in one of %rsi, %rdx, %rcx, %r8 and %r9 registers. In the case of _Bool (i1) it says that the

On May 15, 2008, at 12:14 PM, Duncan Sands wrote: > Hi Evan, > >> If you are using a non-C ABI, then you may not need to do the >> promotion at all. However, if you do need to do the promotion, you >> need to know the type of "int". > > how does this work for parameters. Suppose I have an i1 parameter. > The AMD64 ABI says it is passed in one of %rsi,

> >> If you are using a non-C ABI, then you may not need to do the > >> promotion at all. However, if you do need to do the promotion, you > >> need to know the type of "int". > > > > how does this work for parameters. Suppose I have an i1 parameter. > > The AMD64 ABI says it is passed in one of %rsi, %rdx, %rcx, %r8 and > > %r9

Chris, Regardless of the optimization problem that we had discussions before, I think we all agreed that promotion of return value should take place in the front-end... Now I have a suggestion: In the message below you laid out the suggested IR for "char foo()" when its return value is promoted to i32 in front-end. You have applied the promotion both at the definition of function and