similar to: [LLVMdev] ipsccp vs getelementptr

Hi, I found a mysterious behavior of LLVM optimizer. I compiled the following code by clang -emit-llvm -S: #include <stddef.h> static const struct t {char t[4]; char s;} p = {{}, 'a'}; char f() { return ((char*)&p)[offsetof(struct t, s)]; } then I obtained the following LLVM IR: %struct.t = type { [4 x i8], i8 } @p = constant %struct.t { [4 x i8] zeroinitializer, i8 97

Dump the IR before newgvn and run through opt -newgvn. It should crash. I'm not familiar with your frontend but you might want to use -mllvm -opt-bisect-limit. On Sep 17, 2017 1:06 PM, "Andrew Kelley" <superjoe30 at gmail.com> wrote: Valgrind is strictly better than address sanitizer, is that right? It runs valgrind-clean: [nix-shell:~/dev/zig/build-llvm5-debug]$ valgrind

Hi all, Let's see an example (from Alexandre Isoard) first: **************************************************************************************** ; RUN: opt -ipsccp -deadargelim -licm -O2 -S < %s @g = internal global i32 0 ; Function Attrs: argmemonly define internal void @foo(i32* nonnull dereferenceable(4) %arg, i32 %val) #0 { entry: store i32 %val, i32* %arg ret void } define

When zig updated to llvm 5 we started hitting this assertion: zig: /home/andy/downloads/llvm-project/llvm/include/llvm/Support/Casting.h:106: static bool llvm::isa_impl_cl<To, const From*>::doit(const From*) [with To = llvm::Instruction; From = llvm::Value]: Assertion `Val && "isa<> used on a null pointer"' failed. I wonder if however this was caused by an

Below is attached a full IR module that can reproduce this issue, but the part to notice is this: %Foo96Bits = type <{ i24, i24, i24, i24 }> define internal fastcc i16 @main.0.1() unnamed_addr #2 !dbg !113 { Entry: %value = alloca %Foo96Bits, align 1 %b = alloca i24, align 4 %0 = bitcast %Foo96Bits* %value to i8*, !dbg !129 call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* bitcast

Can you please open a bug on bugzilla and attach the ir testcase? Your fix doesn't look right (just hiding the assertion failure) On Sep 17, 2017 10:45 AM, "Andrew Kelley via llvm-dev" < llvm-dev at lists.llvm.org> wrote: > What do you think about this patch? > > --- a/llvm/lib/Transforms/Scalar/NewGVN.cpp > +++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp > @@

On 7/14/20 4:34 PM, Hal Finkel via llvm-dev wrote: > > On 7/14/20 11:28 AM, Fangqing Du wrote: >> Thank you Hal and Stefan! >> >> Bug report is filed: https://bugs.llvm.org/show_bug.cgi?id=46717 >> <https://bugs.llvm.org/show_bug.cgi?id=46717> >> >> And Stefan, >> I think 'attributor' is a really nice pass, and can infer more >>

Thank you Hal and Stefan! Bug report is filed: https://bugs.llvm.org/show_bug.cgi?id=46717 And Stefan, I think 'attributor' is a really nice pass, and can infer more precise and useful attributes, which may give more opportunities for optimization. But we shouldn't depend on 'attributor' to correct wrong function attributes, because we cannot run 'attributor' after

Hi, opt -O1 converts the attached test.ll to test_opt.ll. " opt --version LLVM (http://llvm.org/): LLVM version 3.8.0 DEBUG build with assertions. Built Jun 23 2016 (18:32:09). Default target: i686-pc-linux-gnu Host CPU: k8-sse3 " test.ll: " ; ModuleID = 'test.bc' @__mla__system.1 = global i32 0 @0 = internal global [12 x i8] zeroinitializer @1 = internal global

Guess I have found some clues. Some necessary libraries have to be loaded while trying to generate native code or do interpretation. Then another question emerges: Is there a way to determine the necessary libraries in need? And where to locate these necessary libraries? Xiaolong > Hi All, > > I have a program that uses C++ STL a lot. To have the source code for > STL functions, I

Hi, my friends I finally insert the callInst into the hello.bc file.Then I compile the hello.bc to hello.o file and the check.c to check.o file. And I think by link those to .o file togetherI can get the executable ELF file(clang hello.o check.o -o finalfile). But when I link the two objective file, it said "hello.o: In function `main': hello.bc:(.text+0x69): undefined reference to

Your files do not appear to implement the check() function. On Tue, Apr 10, 2012 at 4:57 PM, 15102925731 <zhenkaixd at 126.com> wrote: > Hi, my friends > > I finally insert the callInst into the hello.bc file.Then I compile the > hello.bc to hello.o file and the check.c to check.o file. And I think by > link those to .o file togetherI can get the executable ELF file(clang

using `opt --print-after-all -O3` I see that EarlyCSE is interpreting the call to `ceil` and constant fold: *** IR Dump After Early CSE *** ; Function Attrs: nobuiltin nounwind define i1 @do_test() #2 { Entry: %0 = call fastcc float @ceil(float 0.000000e+00) #6 %1 = call fastcc float @ceil32(float 0.000000e+00) #6 %2 = fcmp fast oeq float 0.000000e+00, %1 ret i1 %2 } So just running `opt

Hi Xialong, > I have a program that uses C++ STL a lot. To have the source code for > STL functions, I undefined "_GLIBCXX_EXTERN_TEMPLATE" in > c++config.h. In spite of this, after compilation (via clang) and > linking (via llvm-ld), the resulting bitcode contains a few declared > functions (with no definitions). > > My question is: In the scenario where some

On Mon, May 4, 2015 at 2:19 PM, Nicholas White <n.j.white at gmail.com> wrote: >> It's not quite the same testcase. > Yes - it's an extension of the first test case that I'd expect to be > optimised out in the same way as my earlier example (i.e., store a > value, read it back and branch on it). If you miss out the > "check.first.array.element" block

Hi All, I have a program that uses C++ STL a lot. To have the source code for STL functions, I undefined "_GLIBCXX_EXTERN_TEMPLATE" in c++config.h. In spite of this, after compilation (via clang) and linking (via llvm-ld), the resulting bitcode contains a few declared functions (with no definitions). My question is: In the scenario where some function definitions are missing in a llvm

So, 90% of the time I've seen this, it was memory corruption, usually use after free. I know I fixed one after 5.0 branched. You should compile with address sanitizer enabled, and I suspect you will find the issue quicky. If not, we really need ir that reproduces it. On Sun, Sep 17, 2017, 12:27 PM Andrew Kelley via llvm-dev < llvm-dev at lists.llvm.org> wrote: > I think I forgot to

Hi Xiaolong, > As Duncan described, "lli -load=libstdc++.dylib ..." works. I, > however, encounted an "Illegal instruction" message, while I was > trying to interpret a large program. are you using the interpreter or the JIT? So, does lli have a debug switch > for dumping out the details for errors? > > Using llc is not that simple, and I have not gotten

Thanks Duncan and Ashok, As Duncan described, "lli -load=libstdc++.dylib ..." works. I, however, encounted an "Illegal instruction" message, while I was trying to interpret a large program. So, does lli have a debug switch for dumping out the details for errors? Using llc is not that simple, and I have not gotten through the compilation process. For instance, "llc -o

---------- Forwarded message ---------- From: charles quarra <charllsnotieneningunputocorreo at gmail.com> Date: 2012/12/13 Subject: error while linking modules with exception handling demo code To: llvmdev at cs.uiuc.edu Hi, I am building a module X with an arithmetic function foo, a module Y with an arithmetic function foo2 that invokes foo. For the invocation be a proper one (being