diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/gimple-predicate-analysis.cc | 83 |
1 files changed, 76 insertions, 7 deletions
diff --git a/gcc/gimple-predicate-analysis.cc b/gcc/gimple-predicate-analysis.cc index 23be4b69..ce2e1d1 100644 --- a/gcc/gimple-predicate-analysis.cc +++ b/gcc/gimple-predicate-analysis.cc @@ -42,6 +42,7 @@ #include "value-query.h" #include "cfganal.h" #include "tree-eh.h" +#include "gimple-fold.h" #include "gimple-predicate-analysis.h" @@ -1174,7 +1175,9 @@ compute_control_dep_chain (basic_block dom_bb, const_basic_block dep_bb, /* Implemented simplifications: - 1) ((x IOR y) != 0) AND (x != 0) is equivalent to (x != 0); + 1a) ((x IOR y) != 0) AND (x != 0) is equivalent to (x != 0); + 1b) [!](X rel y) AND [!](X rel y') where y == y' or both constant + can possibly be simplified 2) (X AND Y) OR (!X AND Y) is equivalent to Y; 3) X OR (!X AND Y) is equivalent to (X OR Y); 4) ((x IAND y) != 0) || (x != 0 AND y != 0)) is equivalent to @@ -1184,11 +1187,11 @@ compute_control_dep_chain (basic_block dom_bb, const_basic_block dep_bb, PREDS is the predicate chains, and N is the number of chains. */ -/* Implement rule 1 above. PREDS is the AND predicate to simplify +/* Implement rule 1a above. PREDS is the AND predicate to simplify in place. */ static void -simplify_1 (pred_chain &chain) +simplify_1a (pred_chain &chain) { bool simplified = false; pred_chain s_chain = vNULL; @@ -1245,6 +1248,66 @@ simplify_1 (pred_chain &chain) chain = s_chain; } +/* Implement rule 1b above. PREDS is the AND predicate to simplify + in place. Returns true if CHAIN simplifies to true. */ + +static bool +simplify_1b (pred_chain &chain) +{ + for (unsigned i = 0; i < chain.length (); i++) + { + pred_info &a_pred = chain[i]; + + for (unsigned j = i + 1; j < chain.length (); ++j) + { + pred_info &b_pred = chain[j]; + + if (!operand_equal_p (a_pred.pred_lhs, b_pred.pred_lhs) + || (!operand_equal_p (a_pred.pred_rhs, b_pred.pred_rhs) + && !(CONSTANT_CLASS_P (a_pred.pred_rhs) + && CONSTANT_CLASS_P (b_pred.pred_rhs)))) + continue; + + tree_code a_code = a_pred.cond_code; + if (a_pred.invert) + a_code = invert_tree_comparison (a_code, false); + tree_code b_code = b_pred.cond_code; + if (b_pred.invert) + b_code = invert_tree_comparison (b_code, false); + /* Try to combine X a_code Y && X b_code Y'. */ + tree comb = maybe_fold_and_comparisons (boolean_type_node, + a_code, + a_pred.pred_lhs, + a_pred.pred_rhs, + b_code, + b_pred.pred_lhs, + b_pred.pred_rhs, NULL); + if (!comb) + ; + else if (integer_zerop (comb)) + return true; + else if (integer_truep (comb)) + { + chain.ordered_remove (j); + chain.ordered_remove (i); + i--; + break; + } + else if (COMPARISON_CLASS_P (comb) + && operand_equal_p (a_pred.pred_lhs, TREE_OPERAND (comb, 0))) + { + chain.ordered_remove (j); + a_pred.cond_code = TREE_CODE (comb); + a_pred.pred_rhs = TREE_OPERAND (comb, 1); + a_pred.invert = false; + j--; + } + } + } + + return false; +} + /* Implements rule 2 for the OR predicate PREDS: 2) (X AND Y) OR (!X AND Y) is equivalent to Y. */ @@ -1435,11 +1498,17 @@ predicate::simplify (gimple *use_or_def, bool is_use) dump (dump_file, use_or_def, is_use ? "[USE]:\n" : "[DEF]:\n"); } - unsigned n = m_preds.length (); - for (unsigned i = 0; i < n; i++) - ::simplify_1 (m_preds[i]); + for (unsigned i = 0; i < m_preds.length (); i++) + { + ::simplify_1a (m_preds[i]); + if (::simplify_1b (m_preds[i])) + { + m_preds.ordered_remove (i); + i--; + } + } - if (n < 2) + if (m_preds.length () < 2) return; bool changed; |