[PATCH] cdce: Fix non-call exceptions with signaling nans [PR120951]

[Andrew Pinski]

The cdce code introduces a test for a NaN using the EQ_EXPR code.
The problem is EQ_EXPR can cause an exception with non-call exceptions
and signaling nans turned on. This is now correctly rejected by the verfier
since r16-241-g4c40e3d7b9152f.
The fix is seperate out the comparison into its own statement from the 
GIMPLE_COND.

Bootstrapped and tested on x86_64-linux-gnu with no regressions.

        PR tree-optimization/120951

gcc/ChangeLog:

        * tree-call-cdce.cc (use_internal_fn): For non-call exceptions
        with EQ_EXPR can throw for floating point types, then create
        the EQ_EXPR seperately.

gcc/testsuite/ChangeLog:

        * gcc.dg/torture/pr120951-1.c: New test.

Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
 gcc/testsuite/gcc.dg/torture/pr120951-1.c | 12 ++++++++++++
 gcc/tree-call-cdce.cc                     | 17 +++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr120951-1.c

diff --git a/gcc/testsuite/gcc.dg/torture/pr120951-1.c 
b/gcc/testsuite/gcc.dg/torture/pr120951-1.c
new file mode 100644
index 00000000000..4e2b41deb52
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr120951-1.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-fnon-call-exceptions -fsignaling-nans" } */
+
+/* PR tree-optimization/120951 */
+
+/* cdce would create a trapping comparison inside a condition.
+   tests to make sure that does not happen.  */
+
+double f(double r, double i) {
+   return __builtin_fmod(r, i);
+}
+
diff --git a/gcc/tree-call-cdce.cc b/gcc/tree-call-cdce.cc
index 649c1e2b9f9..3edea754ee4 100644
--- a/gcc/tree-call-cdce.cc
+++ b/gcc/tree-call-cdce.cc
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "builtins.h"
 #include "internal-fn.h"
 #include "tree-dfa.h"
+#include "tree-eh.h"
 
 
 /* This pass serves two closely-related purposes:
@@ -1222,8 +1223,20 @@ use_internal_fn (gcall *call)
     {
       /* Skip the call if LHS == LHS.  If we reach here, EDOM is the only
         valid errno value and it is used iff the result is NaN.  */
-      conds.quick_push (gimple_build_cond (EQ_EXPR, lhs, lhs,
-                                          NULL_TREE, NULL_TREE));
+      /* In the case of non call exceptions, with signaling NaNs, EQ_EXPR
+        can throw an exception and that can't be part of the GIMPLE_COND. */
+      if (flag_exceptions
+         && cfun->can_throw_non_call_exceptions
+         && operation_could_trap_p (EQ_EXPR, true, false, NULL_TREE))
+       {
+         tree b = make_ssa_name (boolean_type_node);
+         conds.quick_push (gimple_build_assign (b, EQ_EXPR, lhs, lhs));
+         conds.quick_push (gimple_build_cond (NE_EXPR, b, boolean_false_node,
+                                              NULL_TREE, NULL_TREE));
+       }
+      else
+       conds.quick_push (gimple_build_cond (EQ_EXPR, lhs, lhs,
+                                            NULL_TREE, NULL_TREE));
       nconds++;
 
       /* Try replacing the original call with a direct assignment to
-- 
2.43.0