seen in gcc-4.2, gcc.misc-tests/bprob-1.c is compiled with -fprofile-arcs and -fbranch-probabilities. gcc.dg/tree-prof/val-prof-1.c is compiled with -fprofile-generate and -fprofile-use. so there won't be any warnings.
2008/4/25 Edmar Wienskoski-RA8797 <[EMAIL PROTECTED]>: > The test case gcc.misc/bprob-1.c is compiled with fprofile-arcs / > fprofile-use. > > The option fprofile-arcs does not enable value profiling. > > At the second stage compilation, the option fprofile-use enables value > profiling. Within tree_find_values_to_profile, if one of the value > optimizations algorithms sees an optimization opportunity, it will push an > histogram on stack. Later, compute_value_histograms will call > get_coverage_counts to load this histogram, but none where generated. > > A warning is issued which means a FAIL under dejagnu. > > I found this problem with bprob-1.c while debugging a new value profile > optimization. But it can be reproduced in any target, with non-modified gcc, > at any optimization level, using one of the value profile test cases and > compiler options fprofile-arcs / fprofile-use (same used with bprob-1.c). > > Here is an example using gcc.dg/tree-prof/val-prof-1.c: > ./gcc-trunk-reference/install_e600/bin/gcc -g -fprofile-arcs val-prof-1.c > -o val-prof-1.x1 > ./val-prof-1.x1 > ./gcc-trunk-reference/install_e600/bin/gcc -g -fprofile-use val-prof-1.c -o > val-prof-1.x2 > val-prof-1.c: In function 'main': > val-prof-1.c:17: warning: no coverage for function 'main' found > > IMHO there are 3 ways to go with this: > 1 - Require user behavior change (create new option -fprofile-arcs-use to > match -fprofile-arcs, mismatch of options is bad user behavior) > 2 - Record on the .gcda file how the first stage were done (fprofile-arcs / > fprofile-generate, etc) and use it to disable other optimizations under > fprofile-use (Does this already exists ?, I am not familiar with the .gcda > layout) > 3 - Let get_coverage_counts ignore inconsistencies when loading data. > > Helps / comments are appreciated. > > Edmar > > > > -- Best wishes! Yours, Lijuan Hai _ _ (_)(_) (,,) =()= ((__)\ _|L\_______/
