commit:     85471c97929d3dfb52f80c556f1803d099dfc01c
Author:     Sam James <sam <AT> gentoo <DOT> org>
AuthorDate: Wed May  8 14:55:04 2024 +0000
Commit:     Sam James <sam <AT> gentoo <DOT> org>
CommitDate: Wed May  8 14:55:04 2024 +0000
URL:        https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=85471c97

sys-devel/gcc: backport fix for Emacs tests to 14.1.0

This _just_ missed the 14.1 release as it got reported a few hours before
the tag was made. Part of Emacs is miscompiled without this and it causes
test failures, so let's pull in the fix now.

Bug: https://gcc.gnu.org/PR14965
Signed-off-by: Sam James <sam <AT> gentoo.org>

 .../gcc/files/gcc-14.1.0-emacs-PR114965.patch      | 106 +++++++++++++++++++++
 sys-devel/gcc/gcc-14.1.0-r1.ebuild                 |  54 +++++++++++
 2 files changed, 160 insertions(+)

diff --git a/sys-devel/gcc/files/gcc-14.1.0-emacs-PR114965.patch 
b/sys-devel/gcc/files/gcc-14.1.0-emacs-PR114965.patch
new file mode 100644
index 000000000000..df4fcee90c51
--- /dev/null
+++ b/sys-devel/gcc/files/gcc-14.1.0-emacs-PR114965.patch
@@ -0,0 +1,106 @@
+https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d54151df3ba0ee3203e0b8cb8f8fcd168a766c51
+https://gcc.gnu.org/PR114965
+
+From d54151df3ba0ee3203e0b8cb8f8fcd168a766c51 Mon Sep 17 00:00:00 2001
+From: Jakub Jelinek <[email protected]>
+Date: Wed, 8 May 2024 10:17:32 +0200
+Subject: [PATCH] reassoc: Fix up optimize_range_tests_to_bit_test [PR114965]
+
+The optimize_range_tests_to_bit_test optimization normally emits a range
+test first:
+          if (entry_test_needed)
+            {
+              tem = build_range_check (loc, optype, unshare_expr (exp),
+                                       false, lowi, high);
+              if (tem == NULL_TREE || is_gimple_val (tem))
+                continue;
+            }
+so during the bit test we already know that exp is in the [lowi, high]
+range, but skips it if we have range info which tells us this isn't
+necessary.
+Also, normally it emits shifts by exp - lowi counter, but has an
+optimization to use just exp counter if the mask isn't a more expensive
+constant in that case and lowi is > 0 and high is smaller than prec.
+
+The following testcase is miscompiled because the two abnormal cases
+are triggered.  The range of exp is [43, 43][48, 48][95, 95], so we on
+64-bit arch decide we don't need the entry test, because 95 - 43 < 64.
+And we also decide to use just exp as counter, because the range test
+tests just for exp == 43 || exp == 48, so high is smaller than 64 too.
+Because 95 is in the exp range, we can't do that, we'd either need to
+do a range test first, i.e.
+if (exp - 43U <= 48U - 43U) if ((1UL << exp) & mask1))
+or need to subtract lowi from the shift counter, i.e.
+if ((1UL << (exp - 43)) & mask2)
+but can't do both unless r.upper_bound () is < prec.
+
+The following patch ensures that.
+
+2024-05-08  Jakub Jelinek  <[email protected]>
+
+       PR tree-optimization/114965
+       * tree-ssa-reassoc.cc (optimize_range_tests_to_bit_test): Don't try to
+       optimize away exp - lowi subtraction from shift count unless entry
+       test is emitted or unless r.upper_bound () is smaller than prec.
+
+       * gcc.c-torture/execute/pr114965.c: New test.
+
+(cherry picked from commit 9adec2d91e62a479474ae79df5b455fd4b8463ba)
+---
+ .../gcc.c-torture/execute/pr114965.c          | 30 +++++++++++++++++++
+ gcc/tree-ssa-reassoc.cc                       |  3 +-
+ 2 files changed, 32 insertions(+), 1 deletion(-)
+ create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr114965.c
+
+diff --git a/gcc/testsuite/gcc.c-torture/execute/pr114965.c 
b/gcc/testsuite/gcc.c-torture/execute/pr114965.c
+new file mode 100644
+index 000000000000..89d68e187015
+--- /dev/null
++++ b/gcc/testsuite/gcc.c-torture/execute/pr114965.c
+@@ -0,0 +1,30 @@
++/* PR tree-optimization/114965 */
++
++static void
++foo (const char *x)
++{
++
++  char a = '0';
++  while (1)
++    {
++      switch (*x)
++      {
++      case '_':
++      case '+':
++        a = *x;
++        x++;
++        continue;
++      default:
++        break;
++      }
++      break;
++    }
++  if (a == '0' || a == '+')
++    __builtin_abort ();
++}
++
++int
++main ()
++{
++  foo ("_");
++}
+diff --git a/gcc/tree-ssa-reassoc.cc b/gcc/tree-ssa-reassoc.cc
+index 61f54f07b577..556ecdebe2d7 100644
+--- a/gcc/tree-ssa-reassoc.cc
++++ b/gcc/tree-ssa-reassoc.cc
+@@ -3418,7 +3418,8 @@ optimize_range_tests_to_bit_test (enum tree_code opcode, 
int first, int length,
+            We can avoid then subtraction of the minimum value, but the
+            mask constant could be perhaps more expensive.  */
+         if (compare_tree_int (lowi, 0) > 0
+-            && compare_tree_int (high, prec) < 0)
++            && compare_tree_int (high, prec) < 0
++            && (entry_test_needed || wi::ltu_p (r.upper_bound (), prec)))
+           {
+             int cost_diff;
+             HOST_WIDE_INT m = tree_to_uhwi (lowi);
+-- 
+2.39.3

diff --git a/sys-devel/gcc/gcc-14.1.0-r1.ebuild 
b/sys-devel/gcc/gcc-14.1.0-r1.ebuild
new file mode 100644
index 000000000000..bf8cde2986d2
--- /dev/null
+++ b/sys-devel/gcc/gcc-14.1.0-r1.ebuild
@@ -0,0 +1,54 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+TOOLCHAIN_PATCH_DEV="sam"
+PATCH_GCC_VER="14.1.0"
+PATCH_VER="1"
+MUSL_VER="1"
+MUSL_GCC_VER="14.1.0"
+PYTHON_COMPAT=( python3_{10..12} )
+
+if [[ -n ${TOOLCHAIN_GCC_RC} ]] ; then
+       # Cheesy hack for RCs
+       MY_PV=$(ver_cut 1).$((($(ver_cut 2) + 1))).$((($(ver_cut 3) - 
1)))-RC-$(ver_cut 5)
+       MY_P=${PN}-${MY_PV}
+       GCC_TARBALL_SRC_URI="mirror://gcc/snapshots/${MY_PV}/${MY_P}.tar.xz"
+       TOOLCHAIN_SET_S=no
+       S="${WORKDIR}"/${MY_P}
+fi
+
+inherit toolchain
+
+if tc_is_live ; then
+       # Needs to be after inherit (for now?), bug #830908
+       EGIT_BRANCH=releases/gcc-$(ver_cut 1)
+elif [[ -z ${TOOLCHAIN_USE_GIT_PATCHES} ]] ; then
+       # Don't keyword live ebuilds
+       #KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips 
~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
+       :;
+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="amd64? ( >=${CATEGORY}/binutils-2.30[cet(-)?] )"
+fi
+
+src_prepare() {
+       local p upstreamed_patches=(
+               # add them here
+       )
+       for p in "${upstreamed_patches[@]}"; do
+               rm -v "${WORKDIR}/patch/${p}" || die
+       done
+
+       toolchain_src_prepare
+
+       eapply "${FILESDIR}"/gcc-14.1.0-emacs-PR114965.patch
+       eapply_user
+}

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