Help about plugins - GIMPLE_COND

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Hi everyone,

I'm playing around on GCC version 11.3 (build Ubuntu), with plugins and passes running on GCC IL, |GIMPLE| in its SSA form to be precise.
But I face an issue with |GIMPLE_COND| statement.

Here is my example statement (output from |debug_gimple_stmt()|):

|if (a_3 == x.0_1) |

Here is the basic bloc containing the statement (dump from |gimple_debug_bb()|):

|;; basic block 2, loop depth 0 ;; pred: ENTRY a_3 = 5; # VUSE <.MEM_4(D)> x.0_1 = x; if (a_3 == x.0_1) goto <bb 3>; [INV] else goto <bb 4>; [INV] ;; succ: 3 ;; 4 |

So, things I'm having trouble with is that when I'm calling |gimple_cond_{true,false}_label()| on the |GIMPLE_COND| statement (casted through |as_a<gcond*>()|), I get a null pointer for both of them, and I do not understand why.

My first intuition is that here |goto|s is not branching on any label but on basic bloc directly somehow explain it. I have been told to use extract_true_false_edges_from_block(), and it do works. Though this is not really what I was expecting as I get an edge and not a tree nor a gimple *. By the way, extract_true_false_edges_from_block() is not mention inside the internal documentation, whereas gimple_cond_{true,false}_label() is.

Anyway, my question is regarding the gimple_cond_{true,false}_label() function. I can't find any use case where this function is not returning nullptr, so what could be its typical use(s) case(s)?

Cheers,

Pierrick Philippe



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