gcov-profile: Allow negative counts of indirect calls [PR105282]

TOPN metrics are histograms that contain overall count and per-bucket
count. Overall count can be negative when two profiles merge and some
of per-bucket metrics are disacarded.

Noticed as an ICE on python PGO build where gcc crashes as:

    during IPA pass: modref
    a.c:36:1: ICE: in stream_out_histogram_value, at value-prof.cc:340
       36 | }
          | ^
    stream_out_histogram_value(output_block*, histogram_value_t*)
            gcc/value-prof.cc:340

gcc/ChangeLog:

	PR gcov-profile/105282
	* value-prof.cc (stream_out_histogram_value): Allow negative counts
	on HIST_TYPE_INDIR_CALL.

diff --git a/gcc/value-prof.cc b/gcc/value-prof.cc
index 9785c7a..c240a18 100644 (file)
--- a/gcc/value-prof.cc
+++ b/gcc/value-prof.cc
@@ -336,6 +336,10 @@ stream_out_histogram_value (struct output_block *ob, histogram_value hist)
        /* Note that the IOR counter tracks pointer values and these can have
           sign bit set.  */
        ;
+      else if (hist->type == HIST_TYPE_INDIR_CALL && i == 0)
+       /* 'all' counter overflow is stored as a negative value. Individual
+          counters and values are expected to be non-negative.  */
+       ;
       else
        gcc_assert (value >= 0);