https://gcc.gnu.org/g:8a6598f4a24306c8aae62c4a591d709a0d1abbc6
commit r16-4025-g8a6598f4a24306c8aae62c4a591d709a0d1abbc6 Author: Andrew Pinski <[email protected]> Date: Fri Sep 19 14:37:04 2025 -0700 fab/gimple-fold: Move __builtin_constant_p folding to gimple-fold [PR121762] This is the first patch in removing fold_all_builtins pass. We want to fold __builtin_constant_p into 0 if we know the argument can't be a constant. So currently that is done in fab pass (though ranger handles it now too). Instead of having fab do it we can check PROP_last_full_fold if set and set it to 0 instead. Note for -Og, fab was the only place which did this conversion, so we need to set PROP_last_full_fold for it; later on fab will be removed and isel will do it instead but that is for another day. Also instead of going through fold_call_stmt to call fold_builtin_constant_p, fold_builtin_constant_p is called directly from gimple_fold_builtin_constant_p. This should speed up the compiling slight :). Note fab was originally added to do this transformation during the development of the ssa branch. Bootstrapped and tested on x86_64-linux-gnu. PR tree-optimization/121762 gcc/ChangeLog: * builtins.cc (fold_builtin_constant_p): Make non-static. * builtins.h (fold_builtin_constant_p): New declaration. * gimple-fold.cc (gimple_fold_builtin_constant_p): New function. (gimple_fold_builtin): Call gimple_fold_builtin_constant_p for BUILT_IN_CONSTANT_P. * tree-ssa-ccp.cc (pass_fold_builtins::execute): Set PROP_last_full_fold on curr_properties. Remove handling of BUILT_IN_CONSTANT_P. Signed-off-by: Andrew Pinski <[email protected]> Diff: --- gcc/builtins.cc | 3 +-- gcc/builtins.h | 1 + gcc/gimple-fold.cc | 31 +++++++++++++++++++++++++++++++ gcc/tree-ssa-ccp.cc | 9 +++------ 4 files changed, 36 insertions(+), 8 deletions(-) diff --git a/gcc/builtins.cc b/gcc/builtins.cc index de3e389c5d4b..78b561529f53 100644 --- a/gcc/builtins.cc +++ b/gcc/builtins.cc @@ -156,7 +156,6 @@ static rtx expand_builtin_stack_address (); static tree stabilize_va_list_loc (location_t, tree, int); static rtx expand_builtin_expect (tree, rtx); static rtx expand_builtin_expect_with_probability (tree, rtx); -static tree fold_builtin_constant_p (tree); static tree fold_builtin_classify_type (tree); static tree fold_builtin_strlen (location_t, tree, tree, tree); static tree fold_builtin_inf (location_t, tree, int); @@ -9150,7 +9149,7 @@ builtin_mathfn_code (const_tree t) /* Fold a call to __builtin_constant_p, if we know its argument ARG will evaluate to a constant. */ -static tree +tree fold_builtin_constant_p (tree arg) { /* We return 1 for a numeric type that's known to be a constant diff --git a/gcc/builtins.h b/gcc/builtins.h index 5a553a9c8365..4f23afad9eed 100644 --- a/gcc/builtins.h +++ b/gcc/builtins.h @@ -139,6 +139,7 @@ extern rtx expand_builtin_crc_table_based (internal_fn, scalar_mode, extern rtx expand_builtin (tree, rtx, rtx, machine_mode, int); extern enum built_in_function builtin_mathfn_code (const_tree); extern tree fold_builtin_expect (location_t, tree, tree, tree, tree); +extern tree fold_builtin_constant_p (tree); extern bool avoid_folding_inline_builtin (tree); extern tree fold_call_expr (location_t, tree, bool); extern tree fold_builtin_call_array (location_t, tree, tree, int, tree *); diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc index 7d130ea38329..229b1b301a4f 100644 --- a/gcc/gimple-fold.cc +++ b/gcc/gimple-fold.cc @@ -69,6 +69,7 @@ along with GCC; see the file COPYING3. If not see #include "varasm.h" #include "internal-fn.h" #include "gimple-range.h" +#include "tree-pass.h" enum strlen_range_kind { /* Compute the exact constant string length. */ @@ -5206,6 +5207,33 @@ gimple_fold_builtin_clear_padding (gimple_stmt_iterator *gsi) return true; } +/* Fold __builtin_constant_p builtin. */ + +static bool +gimple_fold_builtin_constant_p (gimple_stmt_iterator *gsi) +{ + gcall *call = as_a<gcall*>(gsi_stmt (*gsi)); + + if (gimple_call_num_args (call) != 1) + return false; + + tree arg = gimple_call_arg (call, 0); + tree result = fold_builtin_constant_p (arg); + + /* Resolve __builtin_constant_p. If it hasn't been + folded to integer_one_node by now, it's fairly + certain that the value simply isn't constant. */ + if (!result + && (cfun->curr_properties & PROP_last_full_fold)) + result = integer_zero_node; + + if (!result) + return false; + + gimplify_and_update_call_from_tree (gsi, result); + return true; +} + /* Fold the non-target builtin at *GSI and return whether any simplification was made. */ @@ -5375,6 +5403,9 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi) case BUILT_IN_CLEAR_PADDING: return gimple_fold_builtin_clear_padding (gsi); + case BUILT_IN_CONSTANT_P: + return gimple_fold_builtin_constant_p (gsi); + default:; } diff --git a/gcc/tree-ssa-ccp.cc b/gcc/tree-ssa-ccp.cc index 546cafbf7c69..c74f7cc9d0c5 100644 --- a/gcc/tree-ssa-ccp.cc +++ b/gcc/tree-ssa-ccp.cc @@ -4242,6 +4242,9 @@ pass_fold_builtins::execute (function *fun) basic_block bb; unsigned int todoflags = 0; + /* Set last full fold prop if not already set. */ + fun->curr_properties |= PROP_last_full_fold; + FOR_EACH_BB_FN (bb, fun) { gimple_stmt_iterator i; @@ -4280,12 +4283,6 @@ pass_fold_builtins::execute (function *fun) tree result = NULL_TREE; switch (DECL_FUNCTION_CODE (callee)) { - case BUILT_IN_CONSTANT_P: - /* Resolve __builtin_constant_p. If it hasn't been - folded to integer_one_node by now, it's fairly - certain that the value simply isn't constant. */ - result = integer_zero_node; - break; case BUILT_IN_ASSUME_ALIGNED: /* Remove __builtin_assume_aligned. */
