Do not attempt to use a plain subtraction for generating a three-way
comparison result in autopref_rank_for_schedule qsort comparator, as
offsets are not restricted and subtraction may overflow. Open-code
a safe three-way comparison instead.
gcc/ChangeLog:
PR rtl-optimization/109187
* haifa-sched.cc (autopref_rank_for_schedule): Avoid use of overflowing
subtraction in three-way comparison.
gcc/testsuite/ChangeLog:
PR rtl-optimization/109187
* gcc.dg/pr109187.c: New test.
---
I think I can commit this as obvious if no comment in a day, but explicit ack
is always appreciated.
Alexander
gcc/haifa-sched.cc | 2 +-
gcc/testsuite/gcc.dg/pr109187.c | 8 ++++++++
2 files changed, 9 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/pr109187.c
diff --git a/gcc/haifa-sched.cc b/gcc/haifa-sched.cc
index 4efaa9445..e11cc5c35 100644
--- a/gcc/haifa-sched.cc
+++ b/gcc/haifa-sched.cc
@@ -5686,7 +5686,7 @@ autopref_rank_for_schedule (const rtx_insn *insn1, const
rtx_insn *insn2)
if (!irrel1 && !irrel2)
/* Sort memory references from lowest offset to the largest. */
- r = data1->offset - data2->offset;
+ r = (data1->offset > data2->offset) - (data1->offset < data2->offset);
else if (write)
/* Schedule "irrelevant" insns before memory stores to resolve
as many producer dependencies of stores as possible. */
diff --git a/gcc/testsuite/gcc.dg/pr109187.c b/gcc/testsuite/gcc.dg/pr109187.c
new file mode 100644
index 000000000..1ef14a73d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr109187.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 --param sched-autopref-queue-depth=1" } */
+
+void f(int *a)
+{
+ for (;;)
+ asm("" :: "r"(a[-0x10000000]), "r"(a[0x10000000]), "r"(a[0]) : "memory");
+}
--
2.39.1
