On Wed, 15 Jan 2025, Jakub Jelinek wrote:
> Hi!
>
> And here is incremental (for now tested just on the new testcases)
> patch to avoid VRP etc. to replace lhs of musttail call with something else.
OK.
Thanks,
Richard.
> 2025-01-15 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/118430
> * tree-ssa-propagate.cc (may_propagate_copy): Return false if dest
> is lhs of an [[gnu::musttail]] call.
> (substitute_and_fold_dom_walker::before_dom_children): Formatting fix.
>
> * c-c++-common/musttail14.c: Expect lhs on the must tail call calls.
>
> --- gcc/tree-ssa-propagate.cc.jj 2025-01-02 11:23:02.000000000 +0100
> +++ gcc/tree-ssa-propagate.cc 2025-01-15 11:34:38.554602529 +0100
> @@ -870,7 +870,7 @@ substitute_and_fold_dom_walker::before_d
> }
> /* Also fold if we want to fold all statements. */
> else if (substitute_and_fold_engine->fold_all_stmts
> - && fold_stmt (&i, follow_single_use_edges))
> + && fold_stmt (&i, follow_single_use_edges))
> {
> did_replace = true;
> stmt = gsi_stmt (i);
> @@ -1081,6 +1081,13 @@ may_propagate_copy (tree dest, tree orig
> if (TREE_CODE (dest) == SSA_NAME && virtual_operand_p (dest))
> return false;
>
> + /* Keep lhs of [[gnu::musttail]] calls as is, those need to be still
> + tail callable. */
> + if (TREE_CODE (dest) == SSA_NAME
> + && is_gimple_call (SSA_NAME_DEF_STMT (dest))
> + && gimple_call_must_tail_p (as_a <gcall *> (SSA_NAME_DEF_STMT (dest))))
> + return false;
> +
> /* Anything else is OK. */
> return true;
> }
> --- gcc/testsuite/c-c++-common/musttail14.c.jj 2025-01-15
> 11:32:58.048016223 +0100
> +++ gcc/testsuite/c-c++-common/musttail14.c 2025-01-15 11:33:30.982552975
> +0100
> @@ -1,9 +1,9 @@
> /* PR tree-optimization/118430 */
> /* { dg-do compile { target musttail } } */
> /* { dg-options "-O2 -fdump-tree-optimized" } */
> -/* { dg-final { scan-tree-dump-times " bar \\\(\[^\n\r]\*\\\); \\\[tail
> call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> -/* { dg-final { scan-tree-dump-times " freddy \\\(\[^\n\r]\*\\\); \\\[tail
> call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> -/* { dg-final { scan-tree-dump-times " (?:bar|freddy) \\\(\[^\n\r]\*\\\);
> \\\[tail call\\\]" 2 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " \[^\n\r]* = bar \\\(\[^\n\r]\*\\\);
> \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " \[^\n\r]* = freddy
> \\\(\[^\n\r]\*\\\); \\\[tail call\\\] \\\[must tail call\\\]" 1 "optimized" }
> } */
> +/* { dg-final { scan-tree-dump-not " (?:bar|freddy) \\\(\[^\n\r]\*\\\);
> \\\[tail call\\\]" "optimized" } } */
>
> __attribute__ ((noipa)) void
> foo (int x)
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
