Displaying 4 results from an estimated 4 matches for "llvm_dummy_inst2".
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llvm_dummy_inst
2010 Oct 25
2
[LLVMdev] Prevent instruction elimination
...o keep this
information until I run some passes on the *.bc files and manipulate the
code. Then, I delete those "dummy" instructions.
I want to transform this:
#pragma my_pragma {
C/C++ code
C/C++ code
}
into
LLVM_dummy_inst1 , !metadata_info !0
optimized LLVM code
optimized LLVM code
LLVM_dummy_inst2, !metadata_info !1
but if I run this with clang -O2 or with opt -O2, my dummy_inst are removed,
so I cannot find the pragmas in the LLVM IR.
I know that metadata will not prevent the elimination, but I am asking if
there is any way to prevent this, or what kind of instructions I could use
to have...
2010 Oct 25
0
[LLVMdev] Prevent instruction elimination
On Oct 25, 2010, at 2:13 AM, Xinfinity wrote:
>
> Hello,
>
> Does there exist something like a "dummy" instruction that is not removed by
> the optimizers, even if it seems to be dead code?
> I want to use such instructions to carry metadata information, but they
> should have a minimal impact on the code generation and optimization.
Use of metadata will not
2010 Oct 25
0
[LLVMdev] Prevent instruction elimination
...and manipulate the
> code. Then, I delete those "dummy" instructions.
> I want to transform this:
> #pragma my_pragma {
>
> C/C++ code
> C/C++ code
> }
>
> into
> LLVM_dummy_inst1 , !metadata_info !0
> optimized LLVM code
> optimized LLVM code
> LLVM_dummy_inst2, !metadata_info !1
>
> but if I run this with clang -O2 or with opt -O2, my dummy_inst are removed,
> so I cannot find the pragmas in the LLVM IR.
>
> I know that metadata will not prevent the elimination, but I am asking if
> there is any way to prevent this, or what kind of in...
2010 Oct 25
4
[LLVMdev] Prevent instruction elimination
Hello,
Does there exist something like a "dummy" instruction that is not removed by
the optimizers, even if it seems to be dead code?
I want to use such instructions to carry metadata information, but they
should have a minimal impact on the code generation and optimization. I used
an add instruction:
%0 = add i8 1, 2, !pragma_instrument_mem_add !0 ; <i8> [#uses=0]
which