sys-devel/gcc: fix SLP returns_twice issue for 13

This fixes a checking (which we now do by default for pre-releases) ICE
for busybox/xdvik, but it's potentially more serious anyway.

Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469
Signed-off-by: Sam James <sam@gentoo.org>

2 files changed, 123 insertions, 0 deletions

diff --git a/sys-devel/gcc/files/gcc-13.0.1_pre20230409-PR109469-SLP-returns-twice.patch b/sys-devel/gcc/files/gcc-13.0.1_pre20230409-PR109469-SLP-returns-twice.patch
new file mode 100644
index 000000000000..7d45c9e60af8
--- /dev/null
+++ b/sys-devel/gcc/files/gcc-13.0.1_pre20230409-PR109469-SLP-returns-twice.patch
@@ -0,0 +1,66 @@
+https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469
+https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=2d7ad38707e1fd71193d440198cc0726092b9015
+
+From 2d7ad38707e1fd71193d440198cc0726092b9015 Mon Sep 17 00:00:00 2001
+From: Richard Biener <rguenther@suse.de>
+Date: Tue, 11 Apr 2023 16:06:12 +0200
+Subject: [PATCH] tree-optimization/109469 - SLP with returns-twice region
+ start
+
+The following avoids an SLP region starting with a returns-twice
+call where we cannot insert stmts at the head.
+
+	PR tree-optimization/109469
+	* tree-vect-slp.cc (vect_slp_function): Skip region starts with
+	a returns-twice call.
+
+	* gcc.dg/torture/pr109469.c: New testcase.
+--- /dev/null
++++ b/gcc/testsuite/gcc.dg/torture/pr109469.c
+@@ -0,0 +1,15 @@
++/* { dg-do compile } */
++
++__attribute__((returns_twice)) int foo();
++
++struct xio myproc;
++struct xio {
++  void (*read_proc)();
++  void (*write_proc)();
++};
++
++void dummy_write_proc() {
++  switch (foo())
++  default:
++    myproc.read_proc = myproc.write_proc = dummy_write_proc;
++}
+--- a/gcc/tree-vect-slp.cc
++++ b/gcc/tree-vect-slp.cc
+@@ -7671,10 +7671,23 @@ vect_slp_function (function *fun)
+ 	{
+ 	  r |= vect_slp_bbs (bbs, NULL);
+ 	  bbs.truncate (0);
+-	  bbs.quick_push (bb);
+ 	}
+-      else
+-	bbs.safe_push (bb);
++
++      /* We need to be able to insert at the head of the region which
++	 we cannot for region starting with a returns-twice call.  */
++      if (bbs.is_empty ())
++	if (gcall *first = safe_dyn_cast <gcall *> (first_stmt (bb)))
++	  if (gimple_call_flags (first) & ECF_RETURNS_TWICE)
++	    {
++	      if (dump_enabled_p ())
++		dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
++				 "skipping bb%d as start of region as it "
++				 "starts with returns-twice call\n",
++				 bb->index);
++	      continue;
++	    }
++
++      bbs.safe_push (bb);
+ 
+       /* When we have a stmt ending this block and defining a
+ 	 value we have to insert on edges when inserting after it for
+-- 
+2.31.1
diff --git a/sys-devel/gcc/gcc-13.0.1_pre20230409-r2.ebuild b/sys-devel/gcc/gcc-13.0.1_pre20230409-r2.ebuild
new file mode 100644
index 000000000000..527b71d68608
--- /dev/null
+++ b/sys-devel/gcc/gcc-13.0.1_pre20230409-r2.ebuild
@@ -0,0 +1,57 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+TOOLCHAIN_PATCH_DEV="sam"
+PATCH_VER="9"
+PATCH_GCC_VER="13.1.0"
+MUSL_VER="1"
+MUSL_GCC_VER="13.1.0"
+
+if [[ $(ver_cut 3) == 9999 ]] ; then
+	MY_PV_2=$(ver_cut 2)
+	MY_PV_3=$(($(ver_cut 3) - 9998))
+	if [[ ${MY_PV_2} == 0 ]] ; then
+		MY_PV_2=0
+		MY_PV_3=0
+	else
+		MY_PV_2=$(($(ver_cut 2) - 1))
+	fi
+
+	# e.g. 12.2.9999 -> 12.1.1
+	TOOLCHAIN_GCC_PV=$(ver_cut 1).${MY_PV_2}.${MY_PV_3}
+fi
+
+inherit toolchain
+# Needs to be after inherit (for now?), bug #830908
+EGIT_BRANCH=master
+
+# Don't keyword live ebuilds
+if ! tc_is_live && [[ -z ${TOOLCHAIN_USE_GIT_PATCHES} ]] ; then
+#	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
+	KEYWORDS="~loong"
+fi
+
+if [[ ${CATEGORY} != cross-* ]] ; then
+	# Technically only if USE=hardened *too* right now, but no point in complicating it further.
+	# If GCC is enabling CET by default, we need glibc to be built with support for it.
+	# bug #830454
+	RDEPEND="elibc_glibc? ( sys-libs/glibc[cet(-)?] )"
+	DEPEND="${RDEPEND}"
+	BDEPEND=">=${CATEGORY}/binutils-2.30[cet(-)?]"
+fi
+
+src_prepare() {
+	local p upstreamed_patches=(
+		# add them here
+	)
+	for p in "${upstreamed_patches[@]}"; do
+		rm -v "${WORKDIR}/patch/${p}" || die
+	done
+
+	toolchain_src_prepare
+
+	eapply "${FILESDIR}"/${P}-PR109469-SLP-returns-twice.patch
+	eapply_user
+}