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| author | Jakub Jelinek <jakub@redhat.com> | 2025-01-16 09:25:16 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2025-01-16 09:27:54 +0100 |
| commit | 7f5adfd31b3af08924faec36679eaea40a98af19 (patch) | |
| tree | 54fc4cc2847cb1516fbad20a4f41888d4468aab6 | |
| parent | 9c4397cafc5ded9b008a92a55d4e5207e1c2e4e4 (diff) | |
| download | gcc-7f5adfd31b3af08924faec36679eaea40a98af19.zip gcc-7f5adfd31b3af08924faec36679eaea40a98af19.tar.gz gcc-7f5adfd31b3af08924faec36679eaea40a98af19.tar.bz2 | |
tree-ssa-propagate: Special case lhs of musttail calls in may_propagate_copy [PR118430]
This patch ensures that VRP or similar passes don't replace the uses of lhs of
[[gnu::musttail]] calls with some constant (e.g. if the call is known is known
to return a singleton value range) etc. to make it more likely that it is actually
tail callable.
2025-01-16 Jakub Jelinek <jakub@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.
| -rw-r--r-- | gcc/testsuite/c-c++-common/musttail14.c | 6 | ||||
| -rw-r--r-- | gcc/tree-ssa-propagate.cc | 9 |
2 files changed, 11 insertions, 4 deletions
diff --git a/gcc/testsuite/c-c++-common/musttail14.c b/gcc/testsuite/c-c++-common/musttail14.c index e2ab20b..e95bc9b 100644 --- a/gcc/testsuite/c-c++-common/musttail14.c +++ b/gcc/testsuite/c-c++-common/musttail14.c @@ -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) diff --git a/gcc/tree-ssa-propagate.cc b/gcc/tree-ssa-propagate.cc index 94d4401..ec20689 100644 --- a/gcc/tree-ssa-propagate.cc +++ b/gcc/tree-ssa-propagate.cc @@ -870,7 +870,7 @@ substitute_and_fold_dom_walker::before_dom_children (basic_block bb) } /* 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, bool dest_not_abnormal_phi_edge_p) 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; } |