gcc: fix miscompilation on mips64

We've observed strange behaviour of `systemctl status <xxx> on qemumips64.
The output of the command is like `systemctl show <xxx>', which is incorrect.

This patch is from gcc bugzilla's attachment.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81803

The patch hasn't been merged into gcc. But it does solve the above problem.

(From OE-Core rev: 3717c76eb24217c14a22f72fdd8732923729dee8)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 36 insertions, 0 deletions

diff --git a/meta/recipes-devtools/gcc/gcc-7.2.inc b/meta/recipes-devtools/gcc/gcc-7.2.inc
index 5883bc61a6..04edad77cb 100644
--- a/meta/recipes-devtools/gcc/gcc-7.2.inc
+++ b/meta/recipes-devtools/gcc/gcc-7.2.inc
@@ -75,6 +75,7 @@ SRC_URI = "\
            file://0048-gcc-Enable-static-PIE.patch \
            file://fix-segmentation-fault-precompiled-hdr.patch \
            file://0050-RISC-V-Handle-non-legitimate-address-in-riscv_legiti.patch \
+           file://fix-miscompilation-for-O1-on-mips64el.patch \
            ${BACKPORTS} \
 "
 BACKPORTS = "\
diff --git a/meta/recipes-devtools/gcc/gcc-7.2/fix-miscompilation-for-O1-on-mips64el.patch b/meta/recipes-devtools/gcc/gcc-7.2/fix-miscompilation-for-O1-on-mips64el.patch
new file mode 100644
index 0000000000..28020b0e3b
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc-7.2/fix-miscompilation-for-O1-on-mips64el.patch
@@ -0,0 +1,35 @@
+This patch comes from https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81803
+
+Author: mpf <mpf@138bc75d-0d04-0410-961f-82ee72b054a4>
+
+This patch hasn't been merged into gcc. But it does solve the problem of
+strange behaviour of `systemd status <xxx>' on qemumips64.
+
+Upstream-Status: Pending [Taken from gcc bugzilla's attachment]
+
+Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
+---
+ gcc/lra-constraints.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
+index c8bc9b9a66f..6d319662b09 100644
+--- a/gcc/lra-constraints.c
++++ b/gcc/lra-constraints.c
+@@ -4235,7 +4235,12 @@ curr_insn_transform (bool check_only_p)
+                          && (goal_alt[i] == NO_REGS
+                              || (simplify_subreg_regno
+                                  (ira_class_hard_regs[goal_alt[i]][0],
+-                                  GET_MODE (reg), byte, mode) >= 0)))))
++                                  GET_MODE (reg), byte, mode) >= 0))))
++                     || (type != OP_IN
++                         && GET_MODE_PRECISION (mode)
++                         < GET_MODE_PRECISION (GET_MODE (reg))
++                         && GET_MODE_SIZE (GET_MODE (reg)) <= UNITS_PER_WORD
++                         && WORD_REGISTER_OPERATIONS))
+                {
+                  /* An OP_INOUT is required when reloading a subreg of a
+                     mode wider than a word to ensure that data beyond the
+-- 
+2.13.0
+