This series of patches fix PR61441. This patch avoids various transformations

with signaling NaN operands when flag_signaling_nans is on, to avoid folding
which would lose exceptions.

Bootstrapped & regression-tested on x86_64-linux-gnu.

gcc/
	* fold-const.c (const_binop): Convert sNaN to qNaN when
	flag_signaling_nans is off.
	(const_unop): Avoid the operation, other than NEGATE and
	ABS, if flag_signaling_nans is on and the operand is an sNaN.
	(fold_convert_const_real_from_real): Avoid the operation if
	flag_signaling_nans is on and the operand is an sNaN.
	(integer_valued_real_unary_p): Update comment stating it
	returns false for sNaN values.
	(integer_valued_real_binary_p, integer_valued_real_call_p): Same.
	(integer_valued_real_single_p): Same.
	(integer_valued_real_invalid_p, integer_valued_real_p): Same.
	* fold-const-call.c (fold_const_pow): Avoid the operation
	if flag_signaling_nans is on and the operand is an sNaN.
	(fold_const_builtin_load_exponent) Same.
	(fold_const_call_sss): Same for CASE_CFN_POWI.
	* gimple-fold.c (gimple_assign_integer_valued_real_p): Same.
	(gimple_call_integer_valued_real_p): Same.
	(gimple_phi_integer_valued_real_p): Same.
	(gimple_stmt_integer_valued_real_p): Same.
	* simplify-rtx.c (simplify_const_unary_operation): Avoid the
	operation if flag_signaling_nans is on and the operand is an sNaN.
	(simplify_const_binary_operation): Same.
	* tree-ssa-math-opts.c (gimple_expand_builtin_pow): Avoid the
	operation if flag_signaling_nans is on and the operand is an sNaN.

	* gcc.dg/pr61441.c: New testcase.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@231901 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 19 insertions, 1 deletions

diff --git a/gcc/fold-const-call.c b/gcc/fold-const-call.c
index 94801d23fde..7d1351c3691 100644
--- a/gcc/fold-const-call.c
+++ b/gcc/fold-const-call.c
@@ -512,7 +512,11 @@ fold_const_pow (real_value *result, const real_value *arg0,
 	  || !real_equal (arg0, &dconst0)))
     {
       bool inexact = real_powi (result, format, arg0, n1);
-      if (flag_unsafe_math_optimizations || !inexact)
+      /* Avoid the folding if flag_signaling_nans is on.  */
+      if (flag_unsafe_math_optimizations
+	  || (!inexact
+	      && !(flag_signaling_nans
+	           && REAL_VALUE_ISSIGNALING_NAN (*arg0))))
 	return true;
     }
 
@@ -541,6 +545,13 @@ fold_const_builtin_load_exponent (real_value *result, const real_value *arg0,
   if (wi::les_p (arg1, -max_exp_adj) || wi::ges_p (arg1, max_exp_adj))
     return false;
 
+  /* Don't perform operation if we honor signaling NaNs and
+     operand is a signaling NaN.  */
+  if (!flag_unsafe_math_optimizations
+      && flag_signaling_nans
+      && REAL_VALUE_ISSIGNALING_NAN (*arg0))
+    return false;
+
   REAL_VALUE_TYPE initial_result;
   real_ldexp (&initial_result, arg0, arg1.to_shwi ());
 
@@ -1202,6 +1213,13 @@ fold_const_call_sss (real_value *result, combined_fn fn,
 						   format));
 
     CASE_CFN_POWI:
+      /* Avoid the folding if flag_signaling_nans is on and
+         operand is a signaling NaN.  */
+      if (!flag_unsafe_math_optimizations
+	  && flag_signaling_nans
+	  && REAL_VALUE_ISSIGNALING_NAN (*arg0))
+        return false;
+
       real_powi (result, format, arg0, arg1.to_shwi ());
       return true;