If combine has added an unconditional trap there will be a new basic
block as well. It will then end up considering the NOTE_INSN_BASIC_BLOCK
as the last_combined_insn, but then it tries to take the DF_INSN_LUID
of that and that dereferences a NULL pointer (since such a note is not
an INSN_P).
This fixes it by not taking non-insns as last_combined_insn.
Bootstrapped and tested on powerpc64-linux {-m32,-m64}.
Segher
2017-03-29 Segher Boessenkool <seg...@kernel.crashing.org>
PR rtl-optimization/80233
* combine.c (combine_instructions): Only take NONDEBUG_INSN_P insns
as last_combined_insn. Do not test for BARRIER_P separately.
gcc/testsuite/
PR rtl-optimization/80233
* gcc.c-torture/compile/pr80233.c: New testcase.
---
gcc/combine.c | 4 ++--
gcc/testsuite/gcc.c-torture/compile/pr80233.c | 22 ++++++++++++++++++++++
2 files changed, 24 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr80233.c
diff --git a/gcc/combine.c b/gcc/combine.c
index 87e9670..88ac475 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -1250,10 +1250,10 @@ combine_instructions (rtx_insn *f, unsigned int nregs)
continue;
while (last_combined_insn
- && last_combined_insn->deleted ())
+ && (!NONDEBUG_INSN_P (last_combined_insn)
+ || last_combined_insn->deleted ()))
last_combined_insn = PREV_INSN (last_combined_insn);
if (last_combined_insn == NULL_RTX
- || BARRIER_P (last_combined_insn)
|| BLOCK_FOR_INSN (last_combined_insn) != this_basic_block
|| DF_INSN_LUID (last_combined_insn) <= DF_INSN_LUID (insn))
last_combined_insn = insn;
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr80233.c
b/gcc/testsuite/gcc.c-torture/compile/pr80233.c
new file mode 100644
index 0000000..eb9b4a4
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr80233.c
@@ -0,0 +1,22 @@
+/* PR rtl-optimization/80233 */
+
+int xg;
+
+void
+t4 (int o9)
+{
+ int it;
+
+ if (o9 == 0)
+ {
+ int fx;
+
+ xg *= it;
+ if (xg == 0)
+ it /= 0;
+
+ fx = (it != 0) ? (xg < 0) : (xg / o9);
+ if (fx != 0)
+ xg = 0;
+ }
+}
--
1.9.3
