Ccmp is not used if the result of the and/ior is used by both
a GIMPLE_COND and a GIMPLE_ASSIGN. This improves the code generation
here by using ccmp in this case.
Two changes is required, first we need to allow the outer statement's
result be used more than once.
The second change is that during the expansion of the gimple, we need
to try using ccmp. This is needed because we don't use expand the ssa
name of the lhs but rather expand directly from the gimple.
A small note on the ccmp_4.c testcase, we should be able to get slightly
better than with this patch but it is one extra instruction compared to
before.
Bootstraped and tested on aarch64-linux-gnu with no regressions.
PR target/100942
gcc/ChangeLog:
* ccmp.cc (ccmp_candidate_p): Add outer argument.
Allow if the outer is true and the lhs is used more
than once.
(expand_ccmp_expr): Update call to ccmp_candidate_p.
* cfgexpand.cc (expand_gimple_stmt_1): Try using ccmp
for binary assignments.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/ccmp_3.c: New test.
* gcc.target/aarch64/ccmp_4.c: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
gcc/ccmp.cc | 9 +++---
gcc/cfgexpand.cc | 25 ++++++++++++++++
gcc/testsuite/gcc.target/aarch64/ccmp_3.c | 20 +++++++++++++
gcc/testsuite/gcc.target/aarch64/ccmp_4.c | 35 +++++++++++++++++++++++
4 files changed, 85 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/ccmp_3.c
create mode 100644 gcc/testsuite/gcc.target/aarch64/ccmp_4.c
diff --git a/gcc/ccmp.cc b/gcc/ccmp.cc
index 1bd6fadea35..a274f8c3d53 100644
--- a/gcc/ccmp.cc
+++ b/gcc/ccmp.cc
@@ -92,7 +92,7 @@ ccmp_tree_comparison_p (tree t, basic_block bb)
/* Check whether G is a potential conditional compare candidate. */
static bool
-ccmp_candidate_p (gimple *g)
+ccmp_candidate_p (gimple *g, bool outer = false)
{
tree lhs, op0, op1;
gimple *gs0, *gs1;
@@ -109,8 +109,9 @@ ccmp_candidate_p (gimple *g)
lhs = gimple_assign_lhs (g);
op0 = gimple_assign_rhs1 (g);
op1 = gimple_assign_rhs2 (g);
- if ((TREE_CODE (op0) != SSA_NAME) || (TREE_CODE (op1) != SSA_NAME)
- || !has_single_use (lhs))
+ if ((TREE_CODE (op0) != SSA_NAME) || (TREE_CODE (op1) != SSA_NAME))
+ return false;
+ if (!outer && !has_single_use (lhs))
return false;
bb = gimple_bb (g);
@@ -284,7 +285,7 @@ expand_ccmp_expr (gimple *g, machine_mode mode)
rtx_insn *last;
rtx tmp;
- if (!ccmp_candidate_p (g))
+ if (!ccmp_candidate_p (g, true))
return NULL_RTX;
last = get_last_insn ();
diff --git a/gcc/cfgexpand.cc b/gcc/cfgexpand.cc
index b860be8bb77..0f9aad8e3eb 100644
--- a/gcc/cfgexpand.cc
+++ b/gcc/cfgexpand.cc
@@ -74,6 +74,7 @@ along with GCC; see the file COPYING3. If not see
#include "output.h"
#include "builtins.h"
#include "opts.h"
+#include "ccmp.h"
/* Some systems use __main in a way incompatible with its use in gcc, in these
cases use the macros NAME__MAIN to give a quoted symbol and SYMBOL__MAIN to
@@ -3972,6 +3973,30 @@ expand_gimple_stmt_1 (gimple *stmt)
if (GET_CODE (target) == SUBREG && SUBREG_PROMOTED_VAR_P (target))
promoted = true;
+ /* Try to expand conditonal compare. */
+ if (targetm.gen_ccmp_first
+ && gimple_assign_rhs_class (assign_stmt) == GIMPLE_BINARY_RHS)
+ {
+ machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
+ gcc_checking_assert (targetm.gen_ccmp_next != NULL);
+ temp = expand_ccmp_expr (stmt, mode);
+ if (temp)
+ {
+ if (promoted)
+ {
+ int unsignedp = SUBREG_PROMOTED_SIGN (target);
+ convert_move (SUBREG_REG (target), temp, unsignedp);
+ }
+ else
+ {
+ temp = force_operand (temp, target);
+ if (temp != target)
+ emit_move_insn (target, temp);
+ }
+ return;
+ }
+ }
+
ops.code = gimple_assign_rhs_code (assign_stmt);
ops.type = TREE_TYPE (lhs);
switch (get_gimple_rhs_class (ops.code))
diff --git a/gcc/testsuite/gcc.target/aarch64/ccmp_3.c
b/gcc/testsuite/gcc.target/aarch64/ccmp_3.c
new file mode 100644
index 00000000000..a2b47fbee14
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/ccmp_3.c
@@ -0,0 +1,20 @@
+/* { dg-options "-O2" } */
+/* PR target/100942 */
+
+void foo(void);
+int f1(int a, int b)
+{
+ int c = a == 0 || b == 0;
+ if (c) foo();
+ return c;
+}
+
+/* We should get one cmp followed by ccmp and one cset. */
+/* { dg-final { scan-assembler "\tccmp\t" } } */
+/* { dg-final { scan-assembler-times "\tcset\t" 1 } } */
+/* { dg-final { scan-assembler-times "\tcmp\t" 1 } } */
+/* And not get 2 cmps and 2 (or more cset) and orr and a cbnz. */
+/* { dg-final { scan-assembler-not "\torr\t" } } */
+/* { dg-final { scan-assembler-not "\tcbnz\t" } } */
+/* { dg-final { scan-assembler-not "\tcbz\t" } } */
+
diff --git a/gcc/testsuite/gcc.target/aarch64/ccmp_4.c
b/gcc/testsuite/gcc.target/aarch64/ccmp_4.c
new file mode 100644
index 00000000000..bc0f57a7c59
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/ccmp_4.c
@@ -0,0 +1,35 @@
+/* { dg-options "-O2" } */
+/* PR target/100942 */
+
+void foo(void);
+int f1(int a, int b, int d)
+{
+ int c = a < 8 || b < 9;
+ int e = d < 11 || c;
+ if (e) foo();
+ return c;
+}
+
+/*
+ We really should get:
+ cmp w0, 7
+ ccmp w1, 8, 4, gt
+ cset w0, le
+ ccmp w2, 10, 4, gt
+ ble .L11
+
+ But we currently get:
+ cmp w0, 7
+ ccmp w1, 8, 4, gt
+ cset w0, le
+ cmp w0, 0
+ ccmp w2, 10, 4, eq
+ ble .L11
+ The middle cmp is not needed.
+ */
+
+/* We should end up with only one cmp and 2 ccmp and 1 cset but currently we
get 2 cmp
+ though. */
+/* { dg-final { scan-assembler-times "\tccmp\t" 2 } } */
+/* { dg-final { scan-assembler-times "\tcset\t" 1 } } */
+/* { dg-final { scan-assembler-times "\tcmp\t" 1 { xfail *-*-* } } } */
--
2.39.3
