On 03/25/2018 04:31 PM, Timothy Arceri wrote:
> Just checking for 2 jumps is not enough to be sure we can do a
> complex loop unroll. We need to make sure we also have also found
> 2 loop terminators.
>
> Without this we were attempting to unroll a loop where the second
> jump was nesed inside multiple ifs which loop analysis is unable
nested
> to detect as a terminator. We ended up splicing out the first
> terminator but failed to actually unroll the loop, this resulted
> in the creation of a possible infinite loop.
>
> Fixes: 646621c66da9 "glsl: make loop unrolling more like the nir unrolling
> path"
>
> https://bugs.freedesktop.org/show_bug.cgi?id=105670
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105670
Based on my understanding of this code, I think this is correct.
Reviewed-by: Ian Romanick <[email protected]>
> ---
> src/compiler/glsl/loop_unroll.cpp | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/compiler/glsl/loop_unroll.cpp
> b/src/compiler/glsl/loop_unroll.cpp
> index 6e06a30fb91..f6efe6475a0 100644
> --- a/src/compiler/glsl/loop_unroll.cpp
> +++ b/src/compiler/glsl/loop_unroll.cpp
> @@ -519,7 +519,7 @@ loop_unroll_visitor::visit_leave(ir_loop *ir)
> * isn't any additional unknown terminators, or any other jumps nested
> * inside futher ifs.
> */
> - if (ls->num_loop_jumps != 2)
> + if (ls->num_loop_jumps != 2 || ls->terminators.length() != 2)
> return visit_continue;
>
> ir_instruction *first_ir =
>
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