| Message ID | 1749039.2VBSkXCst6@polaris |
|---|---|
| State | New |
| Headers | show |
| Series | Fix PR rtl-optimization/89588 | expand |
On Mon, Mar 11, 2019 at 10:05 AM Eric Botcazou <ebotcazou@adacore.com> wrote: > > Hi, > > this is the failure of the assertion: > > /* Should not get here (such loop should be peeled instead). */ > gcc_assert (niter > max_unroll + 1); > > in unroll_loop_constant_iterations on a testcase both containing #pragma GCC > unroll and compiled with -fno-tree-loop-optimize. The proposed fix is just to > disable the pragma altogether when the option is passed. > > Tested on x86_64-suse-linux, OK for mainline and 8 branch? Hmm, this looks fragile - isn't the same effect when using -fdisable-tree-cunroll? That is, it looks like we could "move" the assert to decide_unrolling instead, deciding LPT_NONE? Richard. > > 2019-03-11 Eric Botcazou <ebotcazou@adacore.com> > > PR rtl-optimization/89588 > * tree-cfg.c (replace_loop_annotate_in_block) <annot_expr_unroll_kind>: > Skip annotation and warn if -fno-tree-loop-optimize is specified. > > > 2019-03-11 Eric Botcazou <ebotcazou@adacore.com> > > * c-c++-common/unroll-6.c: New test. > > -- > Eric Botcazou
> Hmm, this looks fragile - isn't the same effect when using > -fdisable-tree-cunroll? Maybe. > That is, it looks like we could "move" the assert to decide_unrolling > instead, deciding LPT_NONE? We already have a guard for the assertion but it is bypassed here. I'm going to commit this (equivalent to Jakub's fixlet) after retesting. PR rtl-optimization/89588 * loop-unroll.c (decide_unroll_constant_iterations): Make guard for explicit unrolling factor more robust.
Index: tree-cfg.c =================================================================== --- tree-cfg.c (revision 269546) +++ tree-cfg.c (working copy) @@ -280,9 +280,16 @@ replace_loop_annotate_in_block (basic_bl loop->safelen = INT_MAX; break; case annot_expr_unroll_kind: - loop->unroll - = (unsigned short) tree_to_shwi (gimple_call_arg (stmt, 2)); - cfun->has_unroll = true; + if (flag_tree_loop_optimize) + { + loop->unroll + = (unsigned short) tree_to_shwi (gimple_call_arg (stmt, 2)); + cfun->has_unroll = true; + } + else + warning_at (gimple_location (stmt), 0, + "pragma GCC unroll disabled by " + "-fno-tree-loop-optimize"); break; case annot_expr_no_vector_kind: loop->dont_vectorize = true;