On 12/7/2021 10:54 PM, Xionghu Luo via Gcc-patches wrote:
r12-4526 cancelled jump thread path rotates loop. It exposes a issue in
profile-estimate when predict_extra_loop_exits, outer loop's exit edge
is marked as inner loop's extra loop exit and set with incorrect
prediction, then a hot inner loop will become cold loop finally through
optimizations, this patch add loop check when searching extra exit edges
to avoid unexpected predict_edge from predict_paths_for_bb.
Regression tested on P8LE, OK for master?
gcc/ChangeLog:
PR middle-end/103270
* predict.c (predict_extra_loop_exits): Add loop parameter.
(predict_loops): Call with loop argument.
gcc/testsuite/ChangeLog:
PR middle-end/103270
* gcc.dg/pr103270.c: New test.
OK
jeff
