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author | Andrew Pinski <apinski@marvell.com> | 2021-06-01 06:48:05 +0000 |
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committer | Andrew Pinski <apinski@marvell.com> | 2021-06-08 22:08:25 +0000 |
commit | c4574d23cb07340918793a5a98ae7bb2988b3791 (patch) | |
tree | f68278ceb99dd9423dc9d0b279dedca082a22fe1 /gcc/tree-ssa-phiopt.c | |
parent | 61fc01806f376a780978a6dea165ec3dadef085b (diff) | |
download | gcc-c4574d23cb07340918793a5a98ae7bb2988b3791.zip gcc-c4574d23cb07340918793a5a98ae7bb2988b3791.tar.gz gcc-c4574d23cb07340918793a5a98ae7bb2988b3791.tar.bz2 |
Improve match_simplify_replacement in phi-opt
This improves match_simplify_replace in phi-opt to handle the
case where there is one cheap (non-call) preparation statement in the
middle basic block similar to xor_replacement and others.
This allows to remove xor_replacement which it does too.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
Thanks,
Andrew Pinski
Changes since v1:
v3 - Just minor changes to using gimple_assign_lhs
instead of gimple_lhs and fixing a comment.
v2 - change the check on the preparation statement to
allow only assignments and no calls and only assignments
that feed into the phi.
gcc/ChangeLog:
PR tree-optimization/25290
* tree-ssa-phiopt.c (xor_replacement): Delete.
(tree_ssa_phiopt_worker): Delete use of xor_replacement.
(match_simplify_replacement): Allow one cheap preparation
statement that can be moved to before the if.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr96928-1.c: Fix testcase for now that ~
happens on the outside of the bit_xor.
Diffstat (limited to 'gcc/tree-ssa-phiopt.c')
-rw-r--r-- | gcc/tree-ssa-phiopt.c | 164 |
1 files changed, 52 insertions, 112 deletions
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c index 969b868..76f4e7e 100644 --- a/gcc/tree-ssa-phiopt.c +++ b/gcc/tree-ssa-phiopt.c @@ -28,6 +28,7 @@ along with GCC; see the file COPYING3. If not see #include "cfghooks.h" #include "tree-pass.h" #include "ssa.h" +#include "tree-ssa.h" #include "optabs-tree.h" #include "insn-config.h" #include "gimple-pretty-print.h" @@ -63,8 +64,6 @@ static bool minmax_replacement (basic_block, basic_block, edge, edge, gphi *, tree, tree); static bool abs_replacement (basic_block, basic_block, edge, edge, gphi *, tree, tree); -static bool xor_replacement (basic_block, basic_block, - edge, edge, gphi *, tree, tree); static bool spaceship_replacement (basic_block, basic_block, edge, edge, gphi *, tree, tree); static bool cond_removal_in_popcount_clz_ctz_pattern (basic_block, basic_block, @@ -353,9 +352,6 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p) else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) cfgchanged = true; else if (!early_p - && xor_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) - cfgchanged = true; - else if (!early_p && cond_removal_in_popcount_clz_ctz_pattern (bb, bb1, e1, e2, phi, arg0, arg1)) @@ -801,14 +797,51 @@ match_simplify_replacement (basic_block cond_bb, basic_block middle_bb, edge true_edge, false_edge; gimple_seq seq = NULL; tree result; - - if (!empty_block_p (middle_bb)) - return false; + gimple *stmt_to_move = NULL; /* Special case A ? B : B as this will always simplify to B. */ if (operand_equal_for_phi_arg_p (arg0, arg1)) return false; + /* If the basic block only has a cheap preparation statement, + allow it and move it once the transformation is done. */ + if (!empty_block_p (middle_bb)) + { + stmt_to_move = last_and_only_stmt (middle_bb); + if (!stmt_to_move) + return false; + + if (gimple_vuse (stmt_to_move)) + return false; + + if (gimple_could_trap_p (stmt_to_move) + || gimple_has_side_effects (stmt_to_move)) + return false; + + if (gimple_uses_undefined_value_p (stmt_to_move)) + return false; + + /* Allow assignments and not no calls. + As const calls don't match any of the above, yet they could + still have some side-effects - they could contain + gimple_could_trap_p statements, like floating point + exceptions or integer division by zero. See PR70586. + FIXME: perhaps gimple_has_side_effects or gimple_could_trap_p + should handle this. */ + if (!is_gimple_assign (stmt_to_move)) + return false; + + tree lhs = gimple_assign_lhs (stmt_to_move); + gimple *use_stmt; + use_operand_p use_p; + + /* Allow only a statement which feeds into the phi. */ + if (!lhs || TREE_CODE (lhs) != SSA_NAME + || !single_imm_use (lhs, &use_p, &use_stmt) + || use_stmt != phi) + return false; + } + /* At this point we know we have a GIMPLE_COND with two successors. One successor is BB, the other successor is an empty block which falls through into BB. @@ -844,7 +877,17 @@ match_simplify_replacement (basic_block cond_bb, basic_block middle_bb, return false; gsi = gsi_last_bb (cond_bb); - + if (stmt_to_move) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "statement un-sinked:\n"); + print_gimple_stmt (dump_file, stmt_to_move, 0, + TDF_VOPS|TDF_MEMSYMS); + } + gimple_stmt_iterator gsi1 = gsi_for_stmt (stmt_to_move); + gsi_move_before (&gsi1, &gsi); + } if (seq) gsi_insert_seq_before (&gsi, seq, GSI_SAME_STMT); @@ -2592,109 +2635,6 @@ abs_replacement (basic_block cond_bb, basic_block middle_bb, return true; } -/* Optimize x < 0 ? ~y : y into (x >> (prec-1)) ^ y. */ - -static bool -xor_replacement (basic_block cond_bb, basic_block middle_bb, - edge e0 ATTRIBUTE_UNUSED, edge e1, - gphi *phi, tree arg0, tree arg1) -{ - if (!INTEGRAL_TYPE_P (TREE_TYPE (arg1))) - return false; - - /* OTHER_BLOCK must have only one executable statement which must have the - form arg0 = ~arg1 or arg1 = ~arg0. */ - - gimple *assign = last_and_only_stmt (middle_bb); - /* If we did not find the proper one's complement assignment, then we cannot - optimize. */ - if (assign == NULL) - return false; - - /* If we got here, then we have found the only executable statement - in OTHER_BLOCK. If it is anything other than arg = ~arg1 or - arg1 = ~arg0, then we cannot optimize. */ - if (!is_gimple_assign (assign)) - return false; - - if (gimple_assign_rhs_code (assign) != BIT_NOT_EXPR) - return false; - - tree lhs = gimple_assign_lhs (assign); - tree rhs = gimple_assign_rhs1 (assign); - - /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ - if (!(lhs == arg0 && rhs == arg1) && !(lhs == arg1 && rhs == arg0)) - return false; - - gimple *cond = last_stmt (cond_bb); - tree result = PHI_RESULT (phi); - - /* Only relationals comparing arg[01] against zero are interesting. */ - enum tree_code cond_code = gimple_cond_code (cond); - if (cond_code != LT_EXPR && cond_code != GE_EXPR) - return false; - - /* Make sure the conditional is x OP 0. */ - tree clhs = gimple_cond_lhs (cond); - if (TREE_CODE (clhs) != SSA_NAME - || !INTEGRAL_TYPE_P (TREE_TYPE (clhs)) - || TYPE_UNSIGNED (TREE_TYPE (clhs)) - || TYPE_PRECISION (TREE_TYPE (clhs)) != TYPE_PRECISION (TREE_TYPE (arg1)) - || !integer_zerop (gimple_cond_rhs (cond))) - return false; - - /* We need to know which is the true edge and which is the false - edge so that we know if have xor or inverted xor. */ - edge true_edge, false_edge; - extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); - - /* For GE_EXPR, if the true edge goes to OTHER_BLOCK, then we - will need to invert the result. Similarly for LT_EXPR if - the false edge goes to OTHER_BLOCK. */ - edge e; - if (cond_code == GE_EXPR) - e = true_edge; - else - e = false_edge; - - bool invert = e->dest == middle_bb; - - result = duplicate_ssa_name (result, NULL); - - gimple_stmt_iterator gsi = gsi_last_bb (cond_bb); - - int prec = TYPE_PRECISION (TREE_TYPE (clhs)); - gimple *new_stmt - = gimple_build_assign (make_ssa_name (TREE_TYPE (clhs)), RSHIFT_EXPR, clhs, - build_int_cst (integer_type_node, prec - 1)); - gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); - - if (!useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (clhs))) - { - new_stmt = gimple_build_assign (make_ssa_name (TREE_TYPE (result)), - NOP_EXPR, gimple_assign_lhs (new_stmt)); - gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); - } - lhs = gimple_assign_lhs (new_stmt); - - if (invert) - { - new_stmt = gimple_build_assign (make_ssa_name (TREE_TYPE (result)), - BIT_NOT_EXPR, rhs); - gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); - rhs = gimple_assign_lhs (new_stmt); - } - - new_stmt = gimple_build_assign (result, BIT_XOR_EXPR, lhs, rhs); - gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); - - replace_phi_edge_with_variable (cond_bb, e1, phi, result); - - /* Note that we optimized this PHI. */ - return true; -} - /* Auxiliary functions to determine the set of memory accesses which can't trap because they are preceded by accesses to the same memory portion. We do that for MEM_REFs, so we only need to track |