[llvm-dev] segv inside loop on x86_64

David Majnemer via llvm-dev
Tue, 27 Oct 2015 16:14:20 -0000

On Mon, Oct 26, 2015 at 10:13 PM, Matt Arsenault via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

>
> On Oct 27, 2015, at 12:46 AM, Peter McKinna via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
> label_1:                                          ; preds = %label_2,
> %entry
>   %v.87 = load i64, i64* %i, align 8
>   %abs_icmp = icmp slt i64 %v.87, 0
>   %itetmp = alloca i64
>   br i1 %abs_icmp, label %abs_then, label %abs_else
>
>
> You are supposed to have all allocas in the entry block, although I’m not
> sure if this is not expected to work.
>

You can have allocas outside the entry block *but* they are not statically
allocated, they are dynamically allocated.

What this loop is running out of stack because it is allocating 8 bytes on
each iteration and executing ~500000 iterations.


>
>
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