re PR target/77478 (Incorrect code generated with -O3, m32, -msse2 and -ffast-math)

2016-09-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/77478
	* gcc.dg/torture/pr77478.c: New testcase.

From-SVN: r240530

gcc/testsuite/ChangeLog

+2016-09-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/77478
+	* gcc.dg/torture/pr77478.c: New testcase.
+
 2016-09-27  Martin Liska  <mliska@suse.cz>
 
 	PR gcov-profile/7970

gcc/testsuite/gcc.dg/torture/pr77478.c

+/* { dg-do run } */
+/* { dg-additional-options "-ffast-math" } */
+
+static const float A[10] = {1};
+
+float
+foo(float *f, int n)
+{
+  int i, j;
+  float a = 0, b = 0;
+  for (i = n/2; i < n; i++)
+    a += f[i]*.1f;
+  for (i = n/2, j = 0; i < n; i++, j++)
+    b += f[i]*A[j]+a*A[j];
+  return b;
+}
+
+int main()
+{
+  float a[21] = {0};
+  return foo(a+1, 20) + foo(a, 20);
+}