[Bug target/15822] [3.5 Regression] Several alpha testsuite regressions: gcc.c-torture/execute/ieee/fp-cmp-[458].c

["bonzini at gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From bonzini at gnu dot org  2004-06-08 21:41 -------
This fails at -O0 as well:

  int main() {
    return __builtin_isunordered (1.0,4.0);
  }

so this really egregious bug predates my patch: basically, __builtin_is*
functions are broken whenever their arguments are both constants, because we do
not fold them and the alpha expander breaks.  This is quite serious; I do not
know to what extent it applies for 3.4.1, but the patch below seems quite safe.
 I will test it tomorrow on i686-pc-linux-gnu, I would appreciate full testing
on alpha as well.

--- gcc-save/gcc/fold-const.c	2004-05-28 20:30:47.000000000 +0200
+++ gcc/gcc/fold-const.c	2004-06-08 20:00:36.000000000 +0200
@@ -7365,6 +7572,14 @@
     case GT_EXPR:
     case LE_EXPR:
     case GE_EXPR:
+    case UNLE_EXPR:
+    case UNLT_EXPR:
+    case UNGE_EXPR:
+    case UNGT_EXPR:
+    case UNEQ_EXPR:
+    case LTGT_EXPR:
+    case UNORDERED_EXPR:
+    case ORDERED_EXPR:
       /* If one arg is a real or integer constant, put it last.  */
       if (tree_swap_operands_p (arg0, arg1, true))
 	return fold (build2 (swap_tree_comparison (code), type, arg1, arg0));
@@ -9964,8 +10361,22 @@
   tree tem;
   int invert;
 
-  /* From here on, the only cases we handle are when the result is
-     known to be a constant.
+  /* Two real constants can be compared explicitly from the tree
+     code.  */
+  if (TREE_CODE (op0) == REAL_CST && TREE_CODE (op1) == REAL_CST)
+    {
+      REAL_VALUE_TYPE cst0 = TREE_REAL_CST (arg0);
+      REAL_VALUE_TYPE cst1 = TREE_REAL_CST (arg0);
+      int result = real_compare (code, &cst0, &cst1);
+      tem = result ? integer_one_node : integer_zero_node;
+      if (TREE_CODE (type) == BOOLEAN_TYPE)
+        return lang_hooks.truthvalue_conversion (tem);
+      else
+	return tem;
+    }
+
+  /* The only cases we handle here are when the result is known to be a
+     constant.
 
      To compute GT, swap the arguments and do LT.
      To compute GE, do LT and invert the result.
@@ -9980,9 +10391,6 @@
       code = swap_tree_comparison (code);
     }
 
-  /* Note that it is safe to invert for real values here because we
-     will check below in the one case that it matters.  */
-
   tem = NULL_TREE;
   invert = 0;
   if (code == NE_EXPR || code == GE_EXPR)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15822