gcc/ChangeLog:
2018-06-22 Kugan Vivekanandarajah <kug...@linaro.org>
* tree-ssa-phiopt.c (cond_removal_in_popcount_pattern): New.
(tree_ssa_phiopt_worker): Call cond_removal_in_popcount_pattern.
gcc/testsuite/ChangeLog:
2018-06-22 Kugan Vivekanandarajah <kug...@linaro.org>
* gcc.dg/tree-ssa/popcount3.c: New test.
From fa2cca6b186b70668a3334c23ea4b906dac454d4 Mon Sep 17 00:00:00 2001
From: Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org>
Date: Fri, 22 Jun 2018 14:16:21 +1000
Subject: [PATCH 3/3] improve phiopt for builtin popcount
Change-Id: Id1a5997c78fc3ceded3ed7fb0c544ce2bd1a2b34
---
gcc/testsuite/gcc.dg/tree-ssa/popcount3.c | 15 ++++
gcc/tree-ssa-phiopt.c | 113 ++++++++++++++++++++++++++++++
2 files changed, 128 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/popcount3.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c b/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c
new file mode 100644
index 0000000..293beb9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/popcount3.c
@@ -0,0 +1,15 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-phiopt3 -fdump-tree-optimized" } */
+
+int PopCount (long b) {
+ int c = 0;
+
+ while (b) {
+ b &= b - 1;
+ c++;
+ }
+ return c;
+}
+
+/* { dg-final { scan-tree-dump-times "__builtin_popcount" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "if" 0 "phiopt3" } } */
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 8e94f6a..1db5226 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -57,6 +57,8 @@ static bool minmax_replacement (basic_block, basic_block,
edge, edge, gimple *, tree, tree);
static bool abs_replacement (basic_block, basic_block,
edge, edge, gimple *, tree, tree);
+static bool cond_removal_in_popcount_pattern (basic_block, basic_block,
+ edge, edge, gimple *, tree, tree);
static bool cond_store_replacement (basic_block, basic_block, edge, edge,
hash_set<tree> *);
static bool cond_if_else_store_replacement (basic_block, basic_block, basic_block);
@@ -332,6 +334,9 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads)
cfgchanged = true;
else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
cfgchanged = true;
+ else if (cond_removal_in_popcount_pattern (bb, bb1, e1, e2,
+ phi, arg0, arg1))
+ cfgchanged = true;
else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
cfgchanged = true;
}
@@ -1516,6 +1521,114 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
return true;
}
+/* Convert
+
+ <bb 2>
+ if (b_4(D) != 0)
+ goto <bb 3>
+ else
+ goto <bb 4>
+
+ <bb 3>
+ _2 = (unsigned long) b_4(D);
+ _9 = __builtin_popcountl (_2);
+
+ <bb 4>
+ c_12 = PHI <0(2), _9(3)>
+
+ Into
+ <bb 2>
+ _2 = (unsigned long) b_4(D);
+ _9 = __builtin_popcountl (_2);
+
+ <bb 4>
+ c_12 = PHI <_9(2)>
+*/
+
+static bool
+cond_removal_in_popcount_pattern (basic_block cond_bb, basic_block middle_bb,
+ edge e0 ATTRIBUTE_UNUSED, edge e1 ATTRIBUTE_UNUSED,
+ gimple *phi, tree arg0, tree arg1)
+{
+ gimple *cond;
+ gimple_stmt_iterator gsi;
+ gimple *popcount;
+ gimple *cast;
+ tree rhs, lhs, arg;
+ unsigned stmt_count = 0;
+
+ /* Check that
+ _2 = (unsigned long) b_4(D);
+ _9 = __builtin_popcountl (_2);
+ are the only stmts in the middle_bb. */
+
+ for (gsi = gsi_start_bb (middle_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple *stmt = gsi_stmt (gsi);
+ if (is_gimple_debug (stmt))
+ continue;
+ stmt_count++;
+ }
+ if (stmt_count != 2)
+ return false;
+
+ cast = first_stmt (middle_bb);
+ popcount = last_stmt (middle_bb);
+ if (popcount == NULL || cast == NULL)
+ return false;
+
+ /* Check that we have a popcount builtin. */
+ if (!is_gimple_call (popcount)
+ || !gimple_call_builtin_p (popcount, BUILT_IN_NORMAL))
+ return false;
+ tree fndecl = gimple_call_fndecl (popcount);
+ if ((DECL_FUNCTION_CODE (fndecl) != BUILT_IN_POPCOUNT)
+ && (DECL_FUNCTION_CODE (fndecl) != BUILT_IN_POPCOUNTL)
+ && (DECL_FUNCTION_CODE (fndecl) != BUILT_IN_POPCOUNTLL))
+ return false;
+
+ /* Check that we have a cast prior to that. */
+ if (gimple_code (cast) != GIMPLE_ASSIGN
+ || gimple_assign_rhs_code (cast) != NOP_EXPR)
+ return false;
+
+ rhs = gimple_assign_rhs1 (cast);
+ lhs = gimple_get_lhs (popcount);
+ arg = gimple_call_arg (popcount, 0);
+
+ /* Result of the cast stmt is the argument to the builtin. */
+ if (arg != gimple_assign_lhs (cast))
+ return false;
+
+ if (lhs != arg0
+ && lhs != arg1)
+ return false;
+
+ cond = last_stmt (cond_bb);
+
+ /* Cond_bb has a check for b_4 != 0 before calling the popcount
+ builtin. */
+ if (gimple_code (cond) != GIMPLE_COND
+ || gimple_cond_code (cond) != NE_EXPR
+ || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME
+ || rhs != gimple_cond_lhs (cond))
+ return false;
+
+ /* Remove the popcount builtin and cast stmt. */
+ gsi = gsi_for_stmt (popcount);
+ gsi_remove (&gsi, true);
+ gsi = gsi_for_stmt (cast);
+ gsi_remove (&gsi, true);
+
+ /* And insert the popcount builtin and cast stmt before the cond_bb. */
+ gsi = gsi_last_bb (cond_bb);
+ gsi_insert_before (&gsi, popcount, GSI_NEW_STMT);
+ gsi_insert_before (&gsi, cast, GSI_NEW_STMT);
+
+ /* Now update the PHI and remove unneeded bbs. */
+ replace_phi_edge_with_variable (cond_bb, e1, phi, lhs);
+ return true;
+}
/* The function absolute_replacement does the main work of doing the absolute
replacement. Return true if the replacement is done. Otherwise return
--
2.7.4
