obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
should provide you with a source tree that is binary identical
to the one extracted from the above tarball.

if you have obtained the source via the command 'git clone',
however, do note that line-endings of files in your working
directory might differ from line-endings of the respective
files in the upstream repository.

1 files changed, 65 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr28982a.c b/gcc/testsuite/gcc.c-torture/execute/pr28982a.c
new file mode 100644
index 000000000..5660a8d3a
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr28982a.c
@@ -0,0 +1,65 @@
+/* PR rtl-optimization/28982.  Function foo() does the equivalent of:
+
+     float tmp_results[NVARS];
+     for (int i = 0; i < NVARS; i++)
+       {
+	 int inc = incs[i];
+	 float *ptr = ptrs[i], result = 0;
+	 for (int j = 0; j < n; j++)
+	   result += *ptr, ptr += inc;
+	 tmp_results[i] = result;
+       }
+     memcpy (results, tmp_results, sizeof (results));
+
+   but without the outermost loop.  The idea is to create high register
+   pressure and ensure that some INC and PTR variables are spilled.
+
+   On ARM targets, sequences like "result += *ptr, ptr += inc" can
+   usually be implemented using (mem (post_modify ...)), and we do
+   indeed create such MEMs before reload for this testcase.  However,
+   (post_modify ...) is not a valid address for coprocessor loads, so
+   for -mfloat-abi=softfp, reload reloads the POST_MODIFY into a base
+   register.  GCC did not deal correctly with cases where the base and
+   index of the POST_MODIFY are themselves reloaded.  */
+#define NITER 4
+#define NVARS 20
+#define MULTI(X) \
+  X( 0), X( 1), X( 2), X( 3), X( 4), X( 5), X( 6), X( 7), X( 8), X( 9), \
+  X(10), X(11), X(12), X(13), X(14), X(15), X(16), X(17), X(18), X(19)
+
+#define DECLAREI(INDEX) inc##INDEX = incs[INDEX]
+#define DECLAREF(INDEX) *ptr##INDEX = ptrs[INDEX], result##INDEX = 0
+#define LOOP(INDEX) result##INDEX += *ptr##INDEX, ptr##INDEX += inc##INDEX
+#define COPYOUT(INDEX) results[INDEX] = result##INDEX
+
+float *ptrs[NVARS];
+float results[NVARS];
+int incs[NVARS];
+
+void __attribute__((noinline))
+foo (int n)
+{
+  int MULTI (DECLAREI);
+  float MULTI (DECLAREF);
+  while (n--)
+    MULTI (LOOP);
+  MULTI (COPYOUT);
+}
+
+float input[NITER * NVARS];
+
+int
+main (void)
+{
+  int i;
+
+  for (i = 0; i < NVARS; i++)
+    ptrs[i] = input + i, incs[i] = i;
+  for (i = 0; i < NITER * NVARS; i++)
+    input[i] = i;
+  foo (NITER);
+  for (i = 0; i < NVARS; i++)
+    if (results[i] != i * NITER * (NITER + 1) / 2)
+      return 1;
+  return 0;
+}