> This exposed a couple of similar bugs in cse.c and postreload-gcse.c: the > code was effectively treating a basic block with a single, abnormal > incoming edge as if the edge was normal.
I've installed the following refined fix, after testing on i586-suse-linux and sparc-sun-solaris2.10. Most EDGE_ABNORMAL edges can very likely be treated normally here, for example EH edges when call-saved registers are considered. The only really problematic ones are EDGE_ABNORMAL_CALL edges when there is a non-local label in the function, because even call-saved registers are not guaranteed to be preserved in this case. 2011-06-02 Eric Botcazou <ebotca...@adacore.com> * cse.c (cse_find_path): Refine change to exclude EDGE_ABNORMAL_CALL edges only, when there is a non-local label in the function. * postreload-gcse.c (bb_has_well_behaved_predecessors): Likewise. -- Eric Botcazou
Index: cse.c =================================================================== --- cse.c (revision 174564) +++ cse.c (working copy) @@ -6193,7 +6193,7 @@ cse_find_path (basic_block first_bb, str e = NULL; if (e - && (e->flags & EDGE_ABNORMAL) == 0 + && !((e->flags & EDGE_ABNORMAL_CALL) && cfun->has_nonlocal_label) && e->dest != EXIT_BLOCK_PTR && single_pred_p (e->dest) /* Avoid visiting basic blocks twice. The large comment Index: postreload-gcse.c =================================================================== --- postreload-gcse.c (revision 174564) +++ postreload-gcse.c (working copy) @@ -912,12 +912,10 @@ get_avail_load_store_reg (rtx insn) static bool bb_has_well_behaved_predecessors (basic_block bb) { - unsigned int edge_count = EDGE_COUNT (bb->preds); edge pred; edge_iterator ei; - if (edge_count == 0 - || (edge_count == 1 && (single_pred_edge (bb)->flags & EDGE_ABNORMAL))) + if (EDGE_COUNT (bb->preds) == 0) return false; FOR_EACH_EDGE (pred, ei, bb->preds) @@ -925,6 +923,9 @@ bb_has_well_behaved_predecessors (basic_ if ((pred->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (pred)) return false; + if ((pred->flags & EDGE_ABNORMAL_CALL) && cfun->has_nonlocal_label) + return false; + if (JUMP_TABLE_DATA_P (BB_END (pred->src))) return false; }