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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@239275 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 29 insertions, 1 deletions

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;