[PATCH] D26014: [ConstantFold] Get the correct vector type when folding a getelementptr instruction with vector indices

[Davide Italiano via llvm-commits]

On Thu, Oct 27, 2016 at 5:03 PM, David Majnemer via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> majnemer added inline comments.
>
>
> ================
> Comment at: test/Transforms/InstCombine/gep-vector.ll:12-15
> +define <8 x i64*> @patatino2() {
> +  %el = getelementptr inbounds i64, i64* undef, <8 x i64> undef
> +  ret <8 x i64*> %el
> +}
> ----------------
> davide wrote:
>> I tried to replace this getelemptr with
>>
>> ```getelementptr inbounds (i64, i64* undef, <8 x i64> undef)```
>> but I get a parser error. Is this asimmetry between `getelementptr` constant expression and `getelementptr` instruction intended, or am I missing something?
> Seems to be a bug in LLVM.
> For example:
>> cat t.ll
> ```
> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> target triple = "x86_64-unknown-linux-gnu"
>
> @GV = global i64 0
>
> define <8 x i64*> @patatino2() {
>   %el = getelementptr inbounds i64, i64* @GV, <8 x i64> <i64 0, i64 1, i64 0, i64 1, i64 0, i64 1, i64 0, i64 1>
>   ret <8 x i64*> %el
> }
> ```
>
>> ~/llvm/Debug+Asserts/bin/opt -S t.ll -O2 | ~/llvm/Debug+Asserts/bin/llc -o -
>> ~/llvm/Debug+Asserts/bin/llc: <stdin>:10:18: error: getelementptr index type missmatch
>>  ret <8 x i64*> getelementptr (i64, i64* @GV, <8 x i64> <i64 0, i64 1, i64 0, i64 1, i64 0, i64 1, i64 0, i64 1>)
>
>
> It passes the verifier but the parser refuses to deal with it. Worth looking into.
>
>

Will try to take a look at it soon. In the meanwhile, so that it
doesn't get lost: https://llvm.org/bugs/show_bug.cgi?id=30816

-- 
Davide

"There are no solved problems; there are only problems that are more
or less solved" -- Henri Poincare