diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.c
new file mode 100644
index 00000000000..69e02bc4d4a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#include "reassoc-46.h"
+
+/* Check that the loop accumulator is added last.  */
+/* { dg-final { scan-tree-dump-times {sum_\d+ = (?:_\d+ \+ sum_\d+|sum_\d+ \+ _\d+)} 1 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.h b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.h
new file mode 100644
index 00000000000..e60b490ea0d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.h
@@ -0,0 +1,33 @@
+#define M 1024
+unsigned int arr1[M];
+unsigned int arr2[M];
+volatile unsigned int sink;
+
+unsigned int
+test (void)
+{
+  unsigned int sum = 0;
+  for (int i = 0; i < M; i++)
+    {
+#ifdef MODIFY
+      /* Modify the loop accumulator using a chain of operations - this should
+         not affect its rank biasing.  */
+      sum |= 1;
+      sum ^= 2;
+#endif
+#ifdef STORE
+      /* Save the loop accumulator into a global variable - this should not
+         affect its rank biasing.  */
+      sink = sum;
+#endif
+#ifdef USE
+      /* Add a tricky use of the loop accumulator - this should prevent its
+         rank biasing.  */
+      i = (i + sum) % M;
+#endif
+      /* Use addends with different ranks.  */
+      sum += arr1[i];
+      sum += arr2[((i ^ 1) + 1) % M];
+    }
+  return sum;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-47.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-47.c
new file mode 100644
index 00000000000..84b51ccddb0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-47.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define MODIFY
+#include "reassoc-46.h"
+
+/* Check that if the loop accumulator is saved into a global variable, it's
+   still added last.  */
+/* { dg-final { scan-tree-dump-times {sum_\d+ = (?:_\d+ \+ sum_\d+|sum_\d+ \+ _\d+)} 1 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-48.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-48.c
new file mode 100644
index 00000000000..53ae8820281
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-48.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define STORE
+#include "reassoc-46.h"
+
+/* Check that if the loop accumulator is modified using a chain of operations
+   other than addition, its new value is still added last.  */
+/* { dg-final { scan-tree-dump-times {sum_\d+ = (?:_\d+ \+ sum_\d+|sum_\d+ \+ _\d+)} 1 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-49.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-49.c
new file mode 100644
index 00000000000..a6941d5ac2b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-49.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define MODIFY
+#define STORE
+#include "reassoc-46.h"
+
+/* Check that if the loop accumulator is both modified using a chain of
+   operations other than addition and stored into a global variable, its new
+   value is still added last.  */
+/* { dg-final { scan-tree-dump-times {sum_\d+ = (?:_\d+ \+ sum_\d+|sum_\d+ \+ _\d+)} 1 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-50.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-50.c
new file mode 100644
index 00000000000..68cd308c4f1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-50.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define MODIFY
+#define USE
+#include "reassoc-46.h"
+
+/* Check that if the loop accumulator has multiple uses inside the loop, it's
+   not forced to the end of the reassociation chain.  */
+/* { dg-final { scan-tree-dump-times {sum_\d+ = (?:_\d+ \+ sum_\d+|sum_\d+ \+ _\d+)} 2 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-51.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-51.c
new file mode 100644
index 00000000000..eaf61f82ab4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-51.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define MODIFY
+#define STORE
+#define USE
+#include "reassoc-46.h"
+
+/* Check that if the loop accumulator has multiple uses inside the loop, it's
+   not forced to the end of the reassociation chain.  */
+/* { dg-final { scan-tree-dump-times {sum_\d+ = (?:_\d+ \+ sum_\d+|sum_\d+ \+ _\d+)} 2 "optimized" } } */