ubsan: Don't test for NaNs if those do not exist (PR97926)

2021-03-22  Segher Boessenkool  <segher@kernel.crashing.org>

	PR target/97926
	* ubsan.c (ubsan_instrument_float_cast): Don't test for unordered if
	there are no NaNs.

diff --git a/gcc/ubsan.c b/gcc/ubsan.c
index d752b897d642a9a51ab7dbd8e28ae27bea1d655b..1089aef639ffd2bae247cf54eda4e871bb4ca555 100644 (file)
--- a/gcc/ubsan.c
+++ b/gcc/ubsan.c
@@ -1890,8 +1890,16 @@ ubsan_instrument_float_cast (location_t loc, tree type, tree expr)
   else
     return NULL_TREE;
 
-  t = fold_build2 (UNLE_EXPR, boolean_type_node, expr, min);
-  tt = fold_build2 (UNGE_EXPR, boolean_type_node, expr, max);
+  if (HONOR_NANS (mode))
+    {
+      t = fold_build2 (UNLE_EXPR, boolean_type_node, expr, min);
+      tt = fold_build2 (UNGE_EXPR, boolean_type_node, expr, max);
+    }
+  else
+    {
+      t = fold_build2 (LE_EXPR, boolean_type_node, expr, min);
+      tt = fold_build2 (GE_EXPR, boolean_type_node, expr, max);
+    }
   t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, tt);
   if (integer_zerop (t))
     return NULL_TREE;