> CCP and other passes ultimatively end up using fold-const.c:const_{unop,binop}
> for constant folding so that is where the fix should go to (or to real.c).
> That
> will automatically handle other passes doing similar transforms.
Thanks for the tip. I will modify my fix and post it.
Regards,
Sujoy
>
> Richard.
>
>> Regards,
>> Sujoy
>>
>>> Thanks,
>>> Richard.
>>>
>>>> Regards,
>>>> Sujoy
>>>>
>>>> 2015-09-01 Sujoy Saraswati <ssarasw...@gmail.com>
>>>>
>>>> PR tree-optimization/61441
>>>> * tree-ssa-ccp.c (convert_snan_to_qnan): Convert sNaN to qNaN when
>>>> flag_signaling_nans is off.
>>>> (ccp_fold_stmt, visit_assignment, visit_cond_stmt): call
>>>> convert_snan_to_qnan to convert sNaN to qNaN on constant folding.
>>>>
>>>> PR tree-optimization/61441
>>>> * gcc.dg/pr61441.c: New testcase.
>>>>
>>>> Index: gcc/tree-ssa-ccp.c
>>>> ===================================================================
>>>> --- gcc/tree-ssa-ccp.c (revision 226965)
>>>> +++ gcc/tree-ssa-ccp.c (working copy)
>>>> @@ -560,6 +560,24 @@ value_to_wide_int (ccp_prop_value_t val)
>>>> return 0;
>>>> }
>>>>
>>>> +/* Convert sNaN to qNaN when flag_signaling_nans is off */
>>>> +
>>>> +static void
>>>> +convert_snan_to_qnan (tree expr)
>>>> +{
>>>> + if (expr
>>>> + && (TREE_CODE (expr) == REAL_CST)
>>>> + && !flag_signaling_nans)
>>>> + {
>>>> + REAL_VALUE_TYPE *d = TREE_REAL_CST_PTR (expr);
>>>> +
>>>> + if (HONOR_NANS (TYPE_MODE (TREE_TYPE (expr)))
>>>> + && REAL_VALUE_ISNAN (*d)
>>>> + && d->signalling)
>>>> + d->signalling = 0;
>>>> + }
>>>> +}
>>>> +
>>>> /* Return the value for the address expression EXPR based on alignment
>>>> information. */
>>>>
>>>> @@ -2156,6 +2174,7 @@ ccp_fold_stmt (gimple_stmt_iterator *gsi)
>>>> if (val.lattice_val != CONSTANT
>>>> || val.mask != 0)
>>>> return false;
>>>> + convert_snan_to_qnan (val.value);
>>>>
>>>> if (dump_file)
>>>> {
>>>> @@ -2197,7 +2216,10 @@ ccp_fold_stmt (gimple_stmt_iterator *gsi)
>>>> bool res;
>>>> if (!useless_type_conversion_p (TREE_TYPE (lhs),
>>>> TREE_TYPE (new_rhs)))
>>>> + {
>>>> new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
>>>> + convert_snan_to_qnan (new_rhs);
>>>> + }
>>>> res = update_call_from_tree (gsi, new_rhs);
>>>> gcc_assert (res);
>>>> return true;
>>>> @@ -2216,6 +2238,7 @@ ccp_fold_stmt (gimple_stmt_iterator *gsi)
>>>> tree new_rhs = fold_builtin_alloca_with_align (stmt);
>>>> if (new_rhs)
>>>> {
>>>> + convert_snan_to_qnan (new_rhs);
>>>> bool res = update_call_from_tree (gsi, new_rhs);
>>>> tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0);
>>>> gcc_assert (res);
>>>> @@ -2260,7 +2283,10 @@ ccp_fold_stmt (gimple_stmt_iterator *gsi)
>>>> {
>>>> tree rhs = unshare_expr (val);
>>>> if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE
>>>> (rhs)))
>>>> + {
>>>> rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs);
>>>> + convert_snan_to_qnan (rhs);
>>>> + }
>>>> gimple_assign_set_rhs_from_tree (gsi, rhs);
>>>> return true;
>>>> }
>>>> @@ -2292,6 +2318,7 @@ visit_assignment (gimple stmt, tree *output_p)
>>>> /* Evaluate the statement, which could be
>>>> either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
>>>> val = evaluate_stmt (stmt);
>>>> + convert_snan_to_qnan (val.value);
>>>>
>>>> /* If STMT is an assignment to an SSA_NAME, we only have one
>>>> value to set. */
>>>> @@ -2324,6 +2351,7 @@ visit_cond_stmt (gimple stmt, edge *taken_edge_p)
>>>> if (val.lattice_val != CONSTANT
>>>> || val.mask != 0)
>>>> return SSA_PROP_VARYING;
>>>> + convert_snan_to_qnan (val.value);
>>>>
>>>> /* Find which edge out of the conditional block will be taken and add it
>>>> to the worklist. If no single edge can be determined statically,
>>>>
>>>> Index: gcc/testsuite/gcc.dg/pr61441.c
>>>> ===================================================================
>>>> --- gcc/testsuite/gcc.dg/pr61441.c (revision 0)
>>>> +++ gcc/testsuite/gcc.dg/pr61441.c (working copy)
>>>> @@ -0,0 +1,17 @@
>>>> +/* { dg-do run } */
>>>> +/* { dg-options "-O1 -lm" } */
>>>> +
>>>> +#define _GNU_SOURCE
>>>> +#include <stdio.h>
>>>> +#include <math.h>
>>>> +
>>>> +int main (void)
>>>> +{
>>>> + float sNaN = __builtin_nansf ("");
>>>> + double x = (double) sNaN;
>>>> + if (issignaling(x))
>>>> + {
>>>> + __builtin_abort();
>>>> + }
>>>> + return 0;
>>>> +}
