similar to: [LLVMdev] Having trouble with GEP

Hi Dirkjan, I get that error when the %str type is undefined (presumably because LLVM doesn't know its alignment requirements so can't lay out the array$str type properly). For example, the following complete program works correctly for me: %str = type {i8*, i64} %array$str = type { i64, [0 x %str] } declare i8* @malloc(i64) define i64 @foo(i64 %objsz) { %array.raw = call i8*

On Wed, Jan 16, 2013 at 8:22 AM, Tim Northover <t.p.northover at gmail.com> wrote: > I get that error when the %str type is undefined (presumably because > LLVM doesn't know its alignment requirements so can't lay out the > array$str type properly). For example, the following complete program > works correctly for me: > > %str = type {i8*, i64} > %array$str =

> Yes: > > %array$str = type { i64, [0 x %str] } > > declare i8* @malloc(i64) > > define i64 @foo(i64 %objsz) { > %array.raw = call i8* @malloc(i64 %objsz); > %array = bitcast i8* %array.raw to %array$str* > %array.data = getelementptr %array$str* %array, i32 0, i32 1 > %ret = ptrtoint [0 x %str]* %array.data to i64 > ret i64 %ret > } >

On Wed, Jan 16, 2013 at 5:18 PM, Eli Bendersky <eliben at google.com> wrote: > I think it makes sense to create a bug report. Looking at the code of > LLParser::ParseGetElementPtr, the error handling appears to be very > simplistic, so I don't think there's any fundamental reason for not > doing a better job there. Filed http://llvm.org/bugs/show_bug.cgi?id=14965,

On Mon, Apr 4, 2011 at 5:02 PM, Arushi Aggarwal <arushi987 at gmail.com> wrote: > > >> Hi, >> Is it correct to convert, >>   %196 = load i32* %195, align 8                  ; <i32> [#uses=1] >>   %197 = zext i32 %196 to i64                     ; <i64> [#uses=1] >>   %198 = ptrtoint i8* %193 to i64                 ; <i64> [#uses=1]

On 4/4/2011 6:45 PM, Eli Friedman wrote: > On Mon, Apr 4, 2011 at 5:02 PM, Arushi Aggarwal<arushi987 at gmail.com> wrote: >> >>> Hi, >>> Is it correct to convert, >>> %196 = load i32* %195, align 8 ;<i32> [#uses=1] >>> %197 = zext i32 %196 to i64 ;<i64> [#uses=1] >>> %198 =

This code is generated for va_arg. %6 = getelementptr inbounds %struct.__va_list_tag* %5, i32 0, i32 3 ; <i8**> [#uses=1] %7 = load i8** %6, align 8 ; <i8*> [#uses=1] %8 = getelementptr inbounds [1 x %struct.__va_list_tag]* %ap, i64 0, i64 0 ; <%struct.__va_list_tag*> [#uses=1] %9 = getelementptr inbounds %struct.__va_list_tag* %8, i32 0, i32 0 ;

Hi, Is it correct to convert, %196 = load i32* %195, align 8 ; <i32> [#uses=1] %197 = zext i32 %196 to i64 ; <i64> [#uses=1] %198 = ptrtoint i8* %193 to i64 ; <i64> [#uses=1] %199 = add i64 %198, %197 ; <i64> [#uses=1] %200 = inttoptr i64 %199 to i8* ; <i8*>

On Mon, Apr 4, 2011 at 7:10 AM, John Criswell <criswell at illinois.edu> wrote: > On 4/4/2011 6:45 PM, Eli Friedman wrote: >> >> On Mon, Apr 4, 2011 at 5:02 PM, Arushi Aggarwal<arushi987 at gmail.com> >>  wrote: >>> >>>> Hi, >>>> Is it correct to convert, >>>>   %196 = load i32* %195, align 8                

Hi, Given this LLVM assembly: @a = global i8* getelementptr (i8* null, i64 mul (i64 ptrtoint (i32* getelementptr (i32* null, i32 1) to i64), i64 2)) llc fails an assertion: llc: /home/jdenny/llvm-svn/include/llvm/Support/Casting.h:202: typename llvm::cast_retty<To, From>::ret_type llvm::cast(const Y&) [with X = llvm::ConstantInt, Y = llvm::Value*]: Assertion `isa<X>(Val)

On Wed, Apr 20, 2011 at 8:08 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > I have a question about when we should apply these pointer aliasing > rules. Do the rules tell us when a load/store is safe? > "Any memory access must be done through a pointer value associated > with an address range of the memory access, otherwise the behavior is > undefined." >

I have a question about when we should apply these pointer aliasing rules. Do the rules tell us when a load/store is safe? "Any memory access must be done through a pointer value associated with an address range of the memory access, otherwise the behavior is undefined." So this means the conversion discussed here is still safe in terms of memory safety, but its meaning after conversion

Joel E. Denny wrote: > Hi, > > Given this LLVM assembly: > > @a = global i8* getelementptr (i8* null, i64 mul (i64 ptrtoint (i32* getelementptr (i32* null, i32 1) to i64), i64 2)) > > llc fails an assertion: > > llc: /home/jdenny/llvm-svn/include/llvm/Support/Casting.h:202: typename llvm::cast_retty<To, From>::ret_type llvm::cast(const Y&) [with X =

Hi, > > Is it correct to convert, > > %196 = load i32* %195, align 8 ; <i32> [#uses=1] > %197 = zext i32 %196 to i64 ; <i64> [#uses=1] > %198 = ptrtoint i8* %193 to i64 ; <i64> [#uses=1] > %199 = add i64 %198, %197 ; <i64> [#uses=1] > %200 = inttoptr i64 %199 to i8*

On 4/20/11 10:08 AM, Jianzhou Zhao wrote: > I have a question about when we should apply these pointer aliasing > rules. Do the rules tell us when a load/store is safe? > "Any memory access must be done through a pointer value associated > with an address range of the memory access, otherwise the behavior is > undefined." I don't think the pointer aliasing rules

Hi Nick, On Tue, 26 Oct 2010, Nick Lewycky wrote: > Joel E. Denny wrote: > > Given this LLVM assembly: > > > > @a = global i8* getelementptr (i8* null, i64 mul (i64 ptrtoint (i32* > > getelementptr (i32* null, i32 1) to i64), i64 2)) > > > > llc fails an assertion: > > > > llc: /home/jdenny/llvm-svn/include/llvm/Support/Casting.h:202:

On Tue, Feb 17, 2015 at 8:56 AM, Antoine Pitrou <antoine at python.org> wrote: > > Hi, > > Dirkjan Ochtman <dirkjan <at> ochtman.nl> writes: > > > > As far as I understand, this change is wanted because the LLVM > > infrastructure derives no value from knowing the types, and there's a > > cost in terms of code spent to support all of it.

Consider the two functions bellow: define i8* @f(i8* %A) { %pti = ptrtoint i8* %A to i64 %add = add i64 %pti, 5 %itp = inttoptr i64 %add to i8* ret i8* %itp} define i8* @g(i8* %A) { %gep = getelementptr i8* %A, i64 5 ret i8* %gep} What, if anything, prevents us from canonicalizing @f to @g?I've heard that this might be in violation of http://llvm.org/docs/LangRef.html#pointeraliasing

Hi, All. Does anybody know about ConstantExpr in llvm? What's it? Since it always appears after llvm optimization such as -O2 level, what is it supposed to be to codegen? I am wondering it represents constant value which can be determined or computed at compile-time(actually is link-time) to improve performance. Although we do not know the actual constant value util the object file is linked.

On Wed, Apr 20, 2011 at 12:20 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Wed, Apr 20, 2011 at 8:08 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> I have a question about when we should apply these pointer aliasing >> rules. Do the rules tell us when a load/store is safe? >> "Any memory access must be done through a pointer value