Add both positive and negative tests.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/reassoc-46.c: New test.
* gcc.dg/tree-ssa/reassoc-46.h: Common code for new tests.
* gcc.dg/tree-ssa/reassoc-47.c: New test.
* gcc.dg/tree-ssa/reassoc-48.c: New test.
* gcc.dg/tree-ssa/reassoc-49.c: New test.
* gcc.dg/tree-ssa/reassoc-50.c: New test.
* gcc.dg/tree-ssa/reassoc-51.c: New test.
---
gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.c | 7 +++++
gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.h | 33 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/reassoc-47.c | 9 ++++++
gcc/testsuite/gcc.dg/tree-ssa/reassoc-48.c | 9 ++++++
gcc/testsuite/gcc.dg/tree-ssa/reassoc-49.c | 11 ++++++++
gcc/testsuite/gcc.dg/tree-ssa/reassoc-50.c | 10 +++++++
gcc/testsuite/gcc.dg/tree-ssa/reassoc-51.c | 11 ++++++++
7 files changed, 90 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-46.h
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-47.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-48.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-49.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-50.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/reassoc-51.c
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" } } */
--
2.31.1
