On Thu, May 8, 2025 at 9:05 PM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> This is like the patch where we don't want to replace `bool_name != 0`
> with `bool_name` but for instead for INTEGER_CST. The only thing
> difference is there are a few different forms for always true/always
> false; only handle it if it was in the canonical form. A few new helpers are
> added for the canonical form detection.
>
> This also replaces the previous version of the patch which did an early
> exit from fold_stmt_1 instead so we can change the non-canonical form
> into a canonical in the end.
OK.
> gcc/ChangeLog:
>
> * gimple.h (gimple_cond_true_canonical_p): New function.
> (gimple_cond_false_canonical_p): New function.
> * gimple-fold.cc (replace_stmt_with_simplification): Return
> false if replacing the operands of GIMPLE_COND with an INTEGER_CST
> and already in canonical form.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/gimple-fold.cc | 15 +++++++++++++--
> gcc/gimple.h | 30 ++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
> index f801e8b6d41..e63fd6f2f2f 100644
> --- a/gcc/gimple-fold.cc
> +++ b/gcc/gimple-fold.cc
> @@ -6258,10 +6258,21 @@ replace_stmt_with_simplification
> (gimple_stmt_iterator *gsi,
> }
> else if (code == INTEGER_CST)
> {
> + /* Make into the canonical form `1 != 0` and `0 != 0`.
> + If already in the canonical form return false
> + saying nothing has been done. */
> if (integer_zerop (ops[0]))
> - gimple_cond_make_false (cond_stmt);
> + {
> + if (gimple_cond_false_canonical_p (cond_stmt))
> + return false;
> + gimple_cond_make_false (cond_stmt);
> + }
> else
> - gimple_cond_make_true (cond_stmt);
> + {
> + if (gimple_cond_true_canonical_p (cond_stmt))
> + return false;
> + gimple_cond_make_true (cond_stmt);
> + }
> }
> else if (!inplace)
> {
> diff --git a/gcc/gimple.h b/gcc/gimple.h
> index 032365f3da2..977ff1c923c 100644
> --- a/gcc/gimple.h
> +++ b/gcc/gimple.h
> @@ -3875,6 +3875,21 @@ gimple_cond_true_p (const gcond *gs)
> return false;
> }
>
> +/* Check if conditional statement GS is in the caonical form of 'if (1 !=
> 0)'. */
> +
> +inline bool
> +gimple_cond_true_canonical_p (const gcond *gs)
> +{
> + tree lhs = gimple_cond_lhs (gs);
> + tree rhs = gimple_cond_rhs (gs);
> + tree_code code = gimple_cond_code (gs);
> + if (code == NE_EXPR
> + && lhs == boolean_true_node
> + && rhs == boolean_false_node)
> + return true;
> + return false;
> +}
> +
> /* Check if conditional statement GS is of the form 'if (1 != 1)',
> 'if (0 != 0)', 'if (1 == 0)' or 'if (0 == 1)' */
>
> @@ -3900,6 +3915,21 @@ gimple_cond_false_p (const gcond *gs)
> return false;
> }
>
> +/* Check if conditional statement GS is in the caonical form of 'if (0 !=
> 0)'. */
> +
> +inline bool
> +gimple_cond_false_canonical_p (const gcond *gs)
> +{
> + tree lhs = gimple_cond_lhs (gs);
> + tree rhs = gimple_cond_rhs (gs);
> + tree_code code = gimple_cond_code (gs);
> + if (code == NE_EXPR
> + && lhs == boolean_false_node
> + && rhs == boolean_false_node)
> + return true;
> + return false;
> +}
> +
> /* Set the code, LHS and RHS of GIMPLE_COND STMT from CODE, LHS and RHS. */
>
> inline void
> --
> 2.43.0
>
