From 9a385c2d3d74ffed78f2ed9ad47b844d2f294105 Mon Sep 17 00:00:00 2001 From: David Malcolm Date: Fri, 20 May 2016 14:20:03 +0000 Subject: Implement CALL_EXPR_MUST_TAIL_CALL This patch implements support for marking CALL_EXPRs as being mandatory for tail-call-optimization. expand_call tries harder to perform the optimization on such CALL_EXPRs, and issues an error if it fails. Currently this flag isn't accessible from any frontend, so the patch uses a plugin for testing the functionality. gcc/ChangeLog: * calls.c (maybe_complain_about_tail_call): New function. (initialize_argument_information): Call maybe_complain_about_tail_call when clearing *may_tailcall. (can_implement_as_sibling_call_p): Call maybe_complain_about_tail_call when returning false. (expand_call): Read CALL_EXPR_MUST_TAIL_CALL and, if set, ensure try_tail_call is set. Call maybe_complain_about_tail_call if tail-call optimization fails. * cfgexpand.c (expand_call_stmt): Initialize CALL_EXPR_MUST_TAIL_CALL from gimple_call_must_tail_p. * gimple-pretty-print.c (dump_gimple_call): Dump gimple_call_must_tail_p. * gimple.c (gimple_build_call_from_tree): Call gimple_call_set_must_tail with the value of CALL_EXPR_MUST_TAIL_CALL. * gimple.h (enum gf_mask): Add GF_CALL_MUST_TAIL_CALL. (gimple_call_set_must_tail): New function. (gimple_call_must_tail_p): New function. * print-tree.c (print_node): Update printing of TREE_STATIC to reflect its use for CALL_EXPR_MUST_TAIL_CALL. * tree-core.h (struct tree_base): Add MUST_TAIL_CALL to the trailing comment listing applicable flags. * tree.h (CALL_EXPR_MUST_TAIL_CALL): New macro. gcc/testsuite/ChangeLog: * gcc.dg/plugin/must-tail-call-1.c: New test case. * gcc.dg/plugin/must-tail-call-2.c: New test case. * gcc.dg/plugin/must_tail_call_plugin.c: New file. * gcc.dg/plugin/plugin.exp (plugin_test_list): Add the above. From-SVN: r236514 --- gcc/gimple-pretty-print.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'gcc/gimple-pretty-print.c') diff --git a/gcc/gimple-pretty-print.c b/gcc/gimple-pretty-print.c index f864268..48edacc 100644 --- a/gcc/gimple-pretty-print.c +++ b/gcc/gimple-pretty-print.c @@ -760,6 +760,8 @@ dump_gimple_call (pretty_printer *buffer, gcall *gs, int spc, int flags) pp_string (buffer, " [return slot optimization]"); if (gimple_call_tail_p (gs)) pp_string (buffer, " [tail call]"); + if (gimple_call_must_tail_p (gs)) + pp_string (buffer, " [must tail call]"); if (fn == NULL) return; -- cgit v1.1