commit: e45f688bab00f0d7af0a79e92c5bf114cbe58723 Author: Sam James <sam <AT> gentoo <DOT> org> AuthorDate: Thu Jun 12 07:27:49 2025 +0000 Commit: Sam James <sam <AT> gentoo <DOT> org> CommitDate: Thu Jun 12 07:27:49 2025 +0000 URL: https://gitweb.gentoo.org/proj/gcc-patches.git/commit/?id=e45f688b
16.0.0: add more patch metadata Now it got posted to the ML. Signed-off-by: Sam James <sam <AT> gentoo.org> 16.0.0/gentoo/75_all_PR120629.patch | 75 +++++++++++++++++++++++++++++++++---- 1 file changed, 68 insertions(+), 7 deletions(-) diff --git a/16.0.0/gentoo/75_all_PR120629.patch b/16.0.0/gentoo/75_all_PR120629.patch index 77b562a..5622107 100644 --- a/16.0.0/gentoo/75_all_PR120629.patch +++ b/16.0.0/gentoo/75_all_PR120629.patch @@ -1,4 +1,50 @@ -https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120629#c22 +https://inbox.sourceware.org/gcc-patches/aEp6IPgAzLdU5pmi@tucnak/ + +From 34ddeb4974ec668ee035735dcf57429c12b079b2 Mon Sep 17 00:00:00 2001 +Message-ID: <34ddeb4974ec668ee035735dcf57429c12b079b2.1749713239.git....@gentoo.org> +From: Jakub Jelinek <[email protected]> +Date: Thu, 12 Jun 2025 08:56:32 +0200 +Subject: [PATCH] expand: Fix up edge splitting for GIMPLE_COND expansion if + there are any PHIs [PR120629] + +Hi! + +My r16-1398 PR120434 ranger during expansion change broke profiled lto +bootstrap on x86_64-linux, the following testcase is reduced from that. + +The problem is during expand_gimple_cond, if we are unlucky that neither +of edge_true and edge_false point to the next basic block, the code +effectively attempts to split the false_edge and make the new bb BB_RTL +with some extra instructions which just arranges to jump. +It does it by creating a new bb, redirecting the false_edge and then +creating a new edge from the new bb to the dest. +Note, we don't have GIMPLE cfg hooks installed anymore and even if we +would, the 3 calls aren't the same as one split_edge with transformation +of the new bb into BB_RTL and adding it some BB_HEAD/BB_END. If +false_edge->dest is BB_RTL or doesn't have PHI nodes (which before my +patch was always the case because), then this works fine, but with +PHI nodes on false_edge->dest redirect_edge_succ will remove the false_edge +from dest->preds (unordered remove which moves into its place the last edge +in the vector) and the new make_edge will then add the new edge as last +in the vector. So, unless false_edge is the last edge in the dest->preds +vector this effectively swaps the last edge in the vector with +false_edge/its new replacement. +gimple_split_edge solves this by temporarily clearing phi_nodes on dest +(not needed when we don't have GIMPLE hooks), then making the new edge +first and redirecting the old edge (plus restoring phi_nodes on dest). +That way the redirection replaces the old edge with the new one and +PHI arguments don't need adjustment. At the cost of temporarily needing +one more edge in the vector and so if unlucky reallocation. +Doing it like that is one of the options (i.e. just move the +make_single_succ_edge call). This patch instead keeps doing what it did +and just swaps two edges again if needed to restore the PHI behavior +- remember edge_false->dest_idx first if there are PHI nodes in +edge_false->dest and afterwards if new edge's dest_idx is different from +the remembered one, swap the new edge with EDGE_PRED (dest, old_dest_idx). +That way PHI arguments are maintained properly as well. Without this +we sometimes just swap PHI arguments. + +Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2025-06-12 Jakub Jelinek <[email protected]> @@ -9,10 +55,17 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120629#c22 latter with the former last pred edge and their dest_idx members. * g++.dg/opt/pr120629.C: New test. +--- + gcc/cfgexpand.cc | 17 ++++++++- + gcc/testsuite/g++.dg/opt/pr120629.C | 53 +++++++++++++++++++++++++++++ + 2 files changed, 69 insertions(+), 1 deletion(-) + create mode 100644 gcc/testsuite/g++.dg/opt/pr120629.C ---- a/gcc/cfgexpand.cc 2025-06-11 19:28:52.462056696 +0200 -+++ g/gcc/cfgexpand.cc 2025-06-12 00:05:27.524152553 +0200 -@@ -3013,6 +3013,9 @@ expand_gimple_cond (basic_block bb, gcon +diff --git a/gcc/cfgexpand.cc b/gcc/cfgexpand.cc +index 49b0b1404200..ce694add0e38 100644 +--- a/gcc/cfgexpand.cc ++++ b/gcc/cfgexpand.cc +@@ -3013,6 +3013,9 @@ expand_gimple_cond (basic_block bb, gcond *stmt) new_bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb); dest = false_edge->dest; @@ -22,7 +75,7 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120629#c22 redirect_edge_succ (false_edge, new_bb); false_edge->flags |= EDGE_FALLTHRU; new_bb->count = false_edge->count (); -@@ -3021,7 +3024,19 @@ expand_gimple_cond (basic_block bb, gcon +@@ -3021,7 +3024,19 @@ expand_gimple_cond (basic_block bb, gcond *stmt) if (loop->latch == bb && loop->header == dest) loop->latch = new_bb; @@ -43,8 +96,11 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120629#c22 if (BARRIER_P (BB_END (new_bb))) BB_END (new_bb) = PREV_INSN (BB_END (new_bb)); update_bb_for_insn (new_bb); ---- a/gcc/testsuite/g++.dg/opt/pr120629.C 2025-06-12 00:13:02.928211946 +0200 -+++ g/gcc/testsuite/g++.dg/opt/pr120629.C 2025-06-12 00:14:26.008117524 +0200 +diff --git a/gcc/testsuite/g++.dg/opt/pr120629.C b/gcc/testsuite/g++.dg/opt/pr120629.C +new file mode 100644 +index 000000000000..70a9cddcd3f2 +--- /dev/null ++++ b/gcc/testsuite/g++.dg/opt/pr120629.C @@ -0,0 +1,53 @@ +// PR middle-end/120629 +// { dg-do run } @@ -99,3 +155,8 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120629#c22 + if (s.b != 0x1234) + __builtin_abort (); +} + +base-commit: ccfd4163970b1aef12b40f49b826bb49f3fc6f2b +-- +2.49.0 +
