When I was checking to making sure that all of the bugs dealing with the case where gimple_can_duplicate_bb_p would return false was fixed, I noticed that the code which was checking if a call statement was returns_twice was checking all call statements rather than just the last statement. Since calling gimple_call_flags has a small non-zero overhead due to a few string comparison, removing the uses of it can have a small performance improvement. In the case of returns_twice functions calls, will always end the basic-block due to the check in stmt_can_terminate_bb_p (and others). So checking only the last statement is a small optimization and will be safe.
Bootstrapped and tested pon x86_64-linux-gnu with no regressions. PR tree-optimization/114301 gcc/ChangeLog: * tree-cfg.cc (gimple_can_duplicate_bb_p): Check returns_twice only on the last call statement rather than all. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com> --- gcc/tree-cfg.cc | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc index b2d47b72084..7fb7b92966b 100644 --- a/gcc/tree-cfg.cc +++ b/gcc/tree-cfg.cc @@ -6495,6 +6495,13 @@ gimple_can_duplicate_bb_p (const_basic_block bb) && gimple_call_internal_p (last) && gimple_call_internal_unique_p (last)) return false; + + /* Prohibit duplication of returns_twice calls, otherwise associated + abnormal edges also need to be duplicated properly. + return_twice functions will always be the last statement. */ + if (is_gimple_call (last) + && (gimple_call_flags (last) & ECF_RETURNS_TWICE)) + return false; } for (gimple_stmt_iterator gsi = gsi_start_bb (CONST_CAST_BB (bb)); @@ -6502,15 +6509,12 @@ gimple_can_duplicate_bb_p (const_basic_block bb) { gimple *g = gsi_stmt (gsi); - /* Prohibit duplication of returns_twice calls, otherwise associated - abnormal edges also need to be duplicated properly. - An IFN_GOMP_SIMT_ENTER_ALLOC/IFN_GOMP_SIMT_EXIT call must be + /* An IFN_GOMP_SIMT_ENTER_ALLOC/IFN_GOMP_SIMT_EXIT call must be duplicated as part of its group, or not at all. The IFN_GOMP_SIMT_VOTE_ANY and IFN_GOMP_SIMT_XCHG_* are part of such a group, so the same holds there. */ if (is_gimple_call (g) - && (gimple_call_flags (g) & ECF_RETURNS_TWICE - || gimple_call_internal_p (g, IFN_GOMP_SIMT_ENTER_ALLOC) + && (gimple_call_internal_p (g, IFN_GOMP_SIMT_ENTER_ALLOC) || gimple_call_internal_p (g, IFN_GOMP_SIMT_EXIT) || gimple_call_internal_p (g, IFN_GOMP_SIMT_VOTE_ANY) || gimple_call_internal_p (g, IFN_GOMP_SIMT_XCHG_BFLY) -- 2.34.1