Displaying 5 results from an estimated 5 matches for "obit1".
2010 May 19
2
[LLVMdev] Intrinsics and dead instruction/code elimination
...of the llvm.*.with.overflow.* intrinsics.
If I have some sequence (> 1) of llvm.*.with.overflow.* intrinsics, as in the form of:
@global = global i32 0
define void @fun() {
entry:
%res1 = call {i32, i1} @llvm.*.with.overflow.i32(i32 %a, i32 %b)
%sum1 = extractvalue {i32, i1} %res, 0
%obit1 = extractvalue {i32, i1} %res, 1
store i32 %obit1, i32* @global
...
%res2 = call {i32, i1} @llvm.*.with.overflow.i32(i32 %a, i32 %b)
%sum2 = extractvalue {i32, i1} %res, 0
%obit2 = extractvalue {i32, i1} %res, 1
store i32 %obit2, i32* @global
}
then I assume an optimisation pass is abl...
2010 May 19
0
[LLVMdev] Intrinsics and dead instruction/code elimination
...;
> If I have some sequence (> 1) of llvm.*.with.overflow.* intrinsics, as in the form of:
>
> @global = global i32 0
>
> define void @fun() {
> entry:
> %res1 = call {i32, i1} @llvm.*.with.overflow.i32(i32 %a, i32 %b)
> %sum1 = extractvalue {i32, i1} %res, 0
> %obit1 = extractvalue {i32, i1} %res, 1
> store i32 %obit1, i32* @global
> ...
> %res2 = call {i32, i1} @llvm.*.with.overflow.i32(i32 %a, i32 %b)
> %sum2 = extractvalue {i32, i1} %res, 0
> %obit2 = extractvalue {i32, i1} %res, 1
> store i32 %obit2, i32* @global
> }
>
> th...
2010 May 19
2
[LLVMdev] Intrinsics and dead instruction/code elimination
...nce (> 1) of llvm.*.with.overflow.* intrinsics, as in the form of:
>>
>> @global = global i32 0
>>
>> define void @fun() {
>> entry:
>> %res1 = call {i32, i1} @llvm.*.with.overflow.i32(i32 %a, i32 %b)
>> %sum1 = extractvalue {i32, i1} %res, 0
>> %obit1 = extractvalue {i32, i1} %res, 1
>> store i32 %obit1, i32* @global
>> ...
>> %res2 = call {i32, i1} @llvm.*.with.overflow.i32(i32 %a, i32 %b)
>> %sum2 = extractvalue {i32, i1} %res, 0
>> %obit2 = extractvalue {i32, i1} %res, 1
>> store i32 %obit2, i32* @global
&g...
2010 May 19
0
[LLVMdev] Intrinsics and dead instruction/code elimination
...> I understand that dead code elimination is able to delete the intrinsic if it is dead. What I'm interested in is whether or not, despite the entire intrinsic not being dead, anything is able to eliminate the setcc on overflow instruction part of the first intrinsic given that the store of obit1 is dead, thus obit1 is not needed, thus extracting the overflow bit from the CFLAGS register via a setcc instruction is no longer needed. I assume nothing is able to perform such optimisation on intrinsics and my guess is that the only option is, as I said, a pass which rewrites the first intrinsic...
2010 May 19
1
[LLVMdev] Intrinsics and dead instruction/code elimination
...;> I understand that dead code elimination is able to delete the intrinsic if it is dead. What I'm interested in is whether or not, despite the entire intrinsic not being dead, anything is able to eliminate the setcc on overflow instruction part of the first intrinsic given that the store of obit1 is dead, thus obit1 is not needed, thus extracting the overflow bit from the CFLAGS register via a setcc instruction is no longer needed. I assume nothing is able to perform such optimisation on intrinsics and my guess is that the only option is, as I said, a pass which rewrites the first intrinsic...