[gcc r15-3703] Match: Add interface match_cond_with_binary_phi for true/false arg

[Pan Li]

https://gcc.gnu.org/g:65e060c7d8b68653ce8dc2029233b3eff5ced587

commit r15-3703-g65e060c7d8b68653ce8dc2029233b3eff5ced587
Author: Pan Li <pan2.li@intel.com>
Date:   Thu Sep 19 11:03:33 2024 +0800

    Match: Add interface match_cond_with_binary_phi for true/false arg
    
    When matching the cond with 2 args phi node, we need to figure out
    which arg of phi node comes from the true edge of cond block, as
    well as the false edge.  This patch would like to add interface
    to perform the action and return the true and false arg in TREE type.
    
    The below test suites are passed for this patch.
    * The rv64gcv fully regression test.
    * The x86 bootstrap test.
    * The x86 fully regression test.
    
    gcc/ChangeLog:
    
            * gimple-match-head.cc (match_cond_with_binary_phi): Add new func
            impl to match binary phi for true and false arg.
    
    Signed-off-by: Pan Li <pan2.li@intel.com>

Diff:
---
 gcc/gimple-match-head.cc | 120 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)

diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc
index 924d3f1e7103..b63b66e9485a 100644
--- a/gcc/gimple-match-head.cc
+++ b/gcc/gimple-match-head.cc
@@ -375,3 +375,123 @@ gimple_bitwise_inverted_equal_p (tree expr1, tree expr2, bool &wascmp, tree (*va
     return true;
   return false;
 }
+
+/*
+ * Return the relevant gcond * of the given phi, as well as the true
+ * and false TREE args of the phi.  Or return nullptr.
+ *
+ * If matched the gcond *, the output argument TREE true_arg and false_arg
+ * will be updated to the relevant args of phi.
+ *
+ * If failed to match, nullptr gcond * will be returned, as well as the output
+ * arguments will be set to NULL_TREE.
+ */
+
+static inline gcond *
+match_cond_with_binary_phi (gphi *phi, tree *true_arg, tree *false_arg)
+{
+  *true_arg = *false_arg = NULL_TREE;
+
+  if (gimple_phi_num_args (phi) != 2)
+    return nullptr;
+
+  basic_block pred_b0 = EDGE_PRED (gimple_bb (phi), 0)->src;
+  basic_block pred_b1 = EDGE_PRED (gimple_bb (phi), 1)->src;
+  edge edge_for_pred_0 = nullptr;
+
+  if (EDGE_COUNT (pred_b0->succs) == 2
+      && EDGE_COUNT (pred_b1->succs) == 1
+      && EDGE_COUNT (pred_b1->preds) == 1
+      && pred_b0 == EDGE_PRED (gimple_bb (phi), 0)->src)
+    /*
+     * +------+
+     * | b0:  |
+     * | def  |       +-----+
+     * | ...  |       | b1: |
+     * | cond |------>| def |
+     * +------+       | ... |
+     *    |           +-----+
+     *    #              |
+     *    |              |
+     *    v              |
+     * +-----+           |
+     * | b2: |           |
+     * | def |<----------+
+     * +-----+
+     * #: edge_for_pred_0.
+     */
+    edge_for_pred_0 = EDGE_PRED (gimple_bb (phi), 0);
+  else if (EDGE_COUNT (pred_b1->succs) == 2
+	   && EDGE_COUNT (pred_b0->succs) == 1
+	   && EDGE_COUNT (pred_b0->preds) == 1
+	   && pred_b1 == EDGE_PRED (pred_b0, 0)->src)
+    /*
+     *                +------+
+     *                | b1:  |
+     * +-----+        | def  |
+     * | b0: |        | ...  |
+     * | def |<---#---| cond |
+     * | ... |        +------+
+     * +-----+           |
+     *    |              |
+     *    |              |
+     *    |              |
+     *    v              |
+     * +-----+           |
+     * | b2: |           |
+     * | def |<----------+
+     * +-----+
+     * #: edge_for_pred_0.
+     */
+    edge_for_pred_0 = EDGE_PRED (pred_b0, 0);
+  else if (EDGE_COUNT (pred_b0->succs) == 1
+	   && EDGE_COUNT (pred_b1->succs) == 1
+	   && EDGE_COUNT (pred_b0->preds) == 1
+	   && EDGE_COUNT (pred_b1->preds) == 1
+	   && EDGE_COUNT (EDGE_PRED (pred_b0, 0)->src->succs) == 2
+	   && EDGE_PRED (pred_b0, 0)->src == EDGE_PRED (pred_b1, 0)->src)
+    /* +------+
+     * | b0:  |
+     * | ...  |       +-----+
+     * | cond |------>| b2: |
+     * +------+       | ... |
+     *    |           +-----+
+     *    #              |
+     *    |              |
+     *    v              |
+     * +-----+           |
+     * | b1: |           |
+     * | ... |           |
+     * +-----+           |
+     *    |              |
+     *    |              |
+     *    v              |
+     * +-----+           |
+     * | b3: |<----------+
+     * | ... |
+     * +-----+
+     * #: edge_for_pred_0.
+     */
+    edge_for_pred_0 = EDGE_PRED (pred_b0, 0);
+
+  if (!edge_for_pred_0)
+    return nullptr;
+
+  gcond *cond = safe_dyn_cast <gcond *> (*gsi_last_bb (edge_for_pred_0->src));
+
+  if (!cond)
+    return nullptr;
+
+  if (edge_for_pred_0->flags & EDGE_TRUE_VALUE)
+    {
+      *true_arg = gimple_phi_arg_def (phi, 0);
+      *false_arg = gimple_phi_arg_def (phi, 1);
+    }
+  else /* Aka edge_for_pred_0->flags & EDGE_FALSE_VALUE  */
+    {
+      *false_arg = gimple_phi_arg_def (phi, 0);
+      *true_arg = gimple_phi_arg_def (phi, 1);
+    }
+
+  return cond;
+}