Fold: Fix up merge_truthop_with_opposite_arm for NaNs [PR95351]

The problem here is that merge_truthop_with_opposite_arm would
use the type of the result of the comparison rather than the operands
of the comparison to figure out if we are honoring NaNs.
This fixes that oversight and now we get the correct results in this
case.

Committed as obvious after a bootstrap/test on x86_64-linux-gnu.

	PR middle-end/95351

gcc/ChangeLog:

	* fold-const.cc (merge_truthop_with_opposite_arm): Use
	the type of the operands of the comparison and not the type
	of the comparison.

gcc/testsuite/ChangeLog:

	* gcc.dg/float_opposite_arm-1.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
(cherry picked from commit 31ce2e993d09dcad1ce139a2848a28de5931056d)

diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index cd410e50d7797db17f9122039010dc9c3e544780..da96ed34a4c371cddbe938b72f02b70bd0c28e9f 100644 (file)
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -6188,7 +6188,6 @@ static tree
 merge_truthop_with_opposite_arm (location_t loc, tree op, tree cmpop,
                                 bool rhs_only)
 {
-  tree type = TREE_TYPE (cmpop);
   enum tree_code code = TREE_CODE (cmpop);
   enum tree_code truthop_code = TREE_CODE (op);
   tree lhs = TREE_OPERAND (op, 0);
@@ -6204,6 +6203,8 @@ merge_truthop_with_opposite_arm (location_t loc, tree op, tree cmpop,
   if (TREE_CODE_CLASS (code) != tcc_comparison)
     return NULL_TREE;
 
+  tree type = TREE_TYPE (TREE_OPERAND (cmpop, 0));
+
   if (rhs_code == truthop_code)
     {
       tree newrhs = merge_truthop_with_opposite_arm (loc, rhs, cmpop, rhs_only);

diff --git a/gcc/testsuite/gcc.dg/float_opposite_arm-1.c b/gcc/testsuite/gcc.dg/float_opposite_arm-1.c
new file mode 100644 (file)
index 0000000..d2dbff3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/float_opposite_arm-1.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-original -fdump-tree-optimized" } */
+/* { dg-add-options ieee } */
+/* PR middle-end/95351 */
+
+int Foo(double possiblyNAN, double b, double c)
+{
+    return (possiblyNAN <= 2.0) || ((possiblyNAN  > 2.0) && (b > c));
+}
+
+/* Make sure we don't remove either >/<=  */
+
+/* { dg-final { scan-tree-dump "possiblyNAN > 2.0e.0" "original" } } */
+/* { dg-final { scan-tree-dump "possiblyNAN_\[0-9\]+.D. > 2.0e.0" "optimized" } } */
+
+/* { dg-final { scan-tree-dump "possiblyNAN <= 2.0e.0" "original" } } */
+/* { dg-final { scan-tree-dump "possiblyNAN_\[0-9\]+.D. <= 2.0e.0" "optimized" } } */