Attached patch fixes phi-opt not optimizing c++ testcase where we have
if (b_4(D) == 0) instead of if (b_4(D) != 0) as shown in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86544
Patch bootstrapped and regression tested on x86_64-linux-gnu with no
new regressions.
Is this OK for trunk?
Thanks,
Kugan
gcc/ChangeLog:
2018-07-18 Kugan Vivekanandarajah
PR middle-end/86544
* tree-ssa-phiopt.c (cond_removal_in_popcount_pattern): Handle
comparison with EQ_EXPR
in last stmt.
gcc/testsuite/ChangeLog:
2018-07-18 Kugan Vivekanandarajah
PR middle-end/86544
* g++.dg/tree-ssa/pr86544.C: New test.
From c482a4225764e0b338abafb7ccea4553f273f5d5 Mon Sep 17 00:00:00 2001
From: Kugan Vivekanandarajah
Date: Wed, 18 Jul 2018 08:14:16 +1000
Subject: [PATCH] fix cpp testcase
Change-Id: Icd59b31faef2ac66beb42990cb69cbbe38c238aa
---
gcc/testsuite/g++.dg/tree-ssa/pr86544.C | 15 +++
gcc/tree-ssa-phiopt.c | 26 +++---
2 files changed, 30 insertions(+), 11 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr86544.C
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr86544.C b/gcc/testsuite/g++.dg/tree-ssa/pr86544.C
new file mode 100644
index 000..8a90089
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr86544.C
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { 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 656f840..1667bad 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1614,8 +1614,22 @@ cond_removal_in_popcount_pattern (basic_block cond_bb, basic_block middle_bb,
arg = gimple_assign_rhs1 (cast);
}
+ 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
+ && gimple_cond_code (cond) != EQ_EXPR)
+ || !integer_zerop (gimple_cond_rhs (cond))
+ || arg != gimple_cond_lhs (cond))
+return false;
+
/* Canonicalize. */
- if (e2->flags & EDGE_TRUE_VALUE)
+ if ((e2->flags & EDGE_TRUE_VALUE
+ && gimple_cond_code (cond) == NE_EXPR)
+ || (e1->flags & EDGE_TRUE_VALUE
+ && gimple_cond_code (cond) == EQ_EXPR))
{
std::swap (arg0, arg1);
std::swap (e1, e2);
@@ -1625,16 +1639,6 @@ cond_removal_in_popcount_pattern (basic_block cond_bb, basic_block middle_bb,
if (lhs != arg0 || !integer_zerop (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
- || !integer_zerop (gimple_cond_rhs (cond))
- || arg != gimple_cond_lhs (cond))
-return false;
-
/* And insert the popcount builtin and cast stmt before the cond_bb. */
gsi = gsi_last_bb (cond_bb);
if (cast)
--
2.7.4
