From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 9 Aug 2016 07:49:14 +0000 (+0200)
Subject: re PR tree-optimization/72824 (Signed floating point zero semantics broken at optimiz... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9e207d6fec83ee36458d59254d3fd40b3752bec2;p=gcc.git

re PR tree-optimization/72824 (Signed floating point zero semantics broken at optimization level -O3 (tree-loop-distribute-patterns))

	PR tree-optimization/72824
	* tree-loop-distribution.c (const_with_all_bytes_same): Verify
	real_zerop is not negative.

	* gcc.c-torture/execute/ieee/pr72824.c: New test.

From-SVN: r239275
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2d96f88466a..e71b548253e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-08-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/72824
+	* tree-loop-distribution.c (const_with_all_bytes_same): Verify
+	real_zerop is not negative.
+
 2016-08-09  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/71802
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9ba1052e768..711778bfb8e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-08-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/72824
+	* gcc.c-torture/execute/ieee/pr72824.c: New test.
+
 2016-08-09  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/71802
diff --git a/gcc/testsuite/gcc.c-torture/execute/ieee/pr72824.c b/gcc/testsuite/gcc.c-torture/execute/ieee/pr72824.c
new file mode 100644
index 00000000000..1c213733ca1
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/ieee/pr72824.c
@@ -0,0 +1,19 @@
+/* PR tree-optimization/72824 */
+
+static inline void
+foo (float *x, float value)
+{
+  int i;
+  for (i = 0; i < 32; ++i)
+    x[i] = value;
+}
+
+int
+main ()
+{
+  float x[32];
+  foo (x, -0.f);
+  if (__builtin_copysignf (1.0, x[3]) != -1.0f)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 181e4e9ed7d..342b9647fe7 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -750,12 +750,40 @@ const_with_all_bytes_same (tree val)
   int i, len;
 
   if (integer_zerop (val)
-      || real_zerop (val)
       || (TREE_CODE (val) == CONSTRUCTOR
           && !TREE_CLOBBER_P (val)
           && CONSTRUCTOR_NELTS (val) == 0))
     return 0;
 
+  if (real_zerop (val))
+    {
+      /* Only return 0 for +0.0, not for -0.0, which doesn't have
+	 an all bytes same memory representation.  Don't transform
+	 -0.0 stores into +0.0 even for !HONOR_SIGNED_ZEROS.  */
+      switch (TREE_CODE (val))
+	{
+	case REAL_CST:
+	  if (!real_isneg (TREE_REAL_CST_PTR (val)))
+	    return 0;
+	  break;
+	case COMPLEX_CST:
+	  if (!const_with_all_bytes_same (TREE_REALPART (val))
+	      && !const_with_all_bytes_same (TREE_IMAGPART (val)))
+	    return 0;
+	  break;
+	case VECTOR_CST:
+	  unsigned int j;
+	  for (j = 0; j < VECTOR_CST_NELTS (val); ++j)
+	    if (const_with_all_bytes_same (VECTOR_CST_ELT (val, i)))
+	      break;
+	  if (j == VECTOR_CST_NELTS (val))
+	    return 0;
+	  break;
+	default:
+	  break;
+	}
+    }
+
   if (CHAR_BIT != 8 || BITS_PER_UNIT != 8)
     return -1;