tree 33cc3a33e3bc89d26b9b971ce1caf274e39b6b44
parent 0c3287e94d7e5483b31ec9a56447ac5af55d35c1
author Juan A. Suarez Romero <jasuarez@igalia.com> 1551264120 +0000
committer Juan A. Suarez Romero <jasuarez@igalia.com> 1551343626 +0100

nir/spirv: return after emitting a branch in block

When emitting a branch in a block, it does not make sense to continue
processing further instructions, as they will not be reachable.

This fixes a nasty case with a loop with a branch that both then-part
and else-part exits the loop:

%1 = OpLabel
     OpLoopMerge %2 %3 None
     OpBranchConditional %false %2 %2
%3 = OpLabel
     OpBranch %1
%2 = OpLabel
    [...]

We know that block %1 will branch always to block %2, which is the merge
block for the loop. And thus a break is emitted. If we keep continuing
processing further instructions, we will be processing the branch
conditional and thus emitting the proper NIR conditional, which leads to
instructions after the break.

This fixes dEQP-VK.graphicsfuzz.continue-and-merge.

CC: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>