This patch add another condition for gimple-cond optimization. Refer to
the following test case.
int foo1 (int data, int res)
{
res = data & 0xf;
res |= res << 4;
if (res < 0x22)
return 0x22;
return res;
}
with the compilation flag "-march=rv64gc_zba_zbb -mabi=lp64d -O2",
before this patch the compilation result is
foo1:
andi a0,a0,15
slliw a5,a0,4
addw a3,a5,a0
li a4,33
add a0,a5,a0
bleu a3,a4,.L5
ret
.L5:
li a0,34
ret
after this patch the compilation result is
foo1:
andi a0,a0,15
slliw a5,a0,4
add a5,a5,a0
li a0,34
max a0,a5,a0
ret
The reason is in the pass_early_vrp, the arg0 of gimple_cond
is replaced,but the PHI node still use the arg0.
The some of evrp pass logs are as follows
gimple_assign <mult_expr, _9, _7, 17, NULL>
gimple_assign <nop_expr, res_5, _9, NULL, NULL>
gimple_cond <le_expr, _9, 33, NULL, NULL>
goto <bb 3>; [INV]
else
goto <bb 4>; [INV]
<bb 3> :
// predicted unlikely by early return (on trees) predictor.
<bb 4> :
# gimple_phi <_2, 34(3), res_5(2)>
The arg0 of gimple_cond is replaced by _9,but the gimple_phi still
uses res_5,it will cause optimization fail of PHI node to MAX_EXPR.
So the next_use_is_phi is added to control the replacement.
gcc/ChangeLog:
* vr-values.cc (next_use_is_phi):
(simplify_using_ranges::simplify_casted_compare):
add new function next_use_is_phi to control the replacement.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/zbb-min-max-04.c: New test.
---
gcc/testsuite/gcc.target/riscv/zbb-min-max-04.c | 14 ++++++++++++++
gcc/vr-values.cc | 15 ++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/zbb-min-max-04.c
diff --git a/gcc/testsuite/gcc.target/riscv/zbb-min-max-04.c
b/gcc/testsuite/gcc.target/riscv/zbb-min-max-04.c
new file mode 100644
index 00000000000..8c3e87a35e0
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/zbb-min-max-04.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zba_zbb -mabi=lp64d" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
+
+int foo1 (int data, int res)
+{
+ res = data & 0xf;
+ res |= res << 4;
+ if (res < 0x22)
+ return 0x22;
+ return res;
+}
+
+/* { dg-final { scan-assembler-times "max\t" 1 } } */
\ No newline at end of file
diff --git a/gcc/vr-values.cc b/gcc/vr-values.cc
index ecb294131b0..1f7a727c638 100644
--- a/gcc/vr-values.cc
+++ b/gcc/vr-values.cc
@@ -1263,6 +1263,18 @@ simplify_using_ranges::simplify_compare_using_ranges_1
(tree_code &cond_code, tr
return happened;
}
+/* Return true if the next use of SSA_NAME is PHI node */
+bool
+next_use_is_phi (tree arg)
+{
+ use_operand_p imm = &(SSA_NAME_IMM_USE_NODE (arg));
+ use_operand_p next = imm->next;
+ if (next && next->loc.stmt
+ && (gimple_code (next->loc.stmt) == GIMPLE_PHI))
+ return true;
+ return false;
+}
+
/* Simplify OP0 code OP1 when OP1 is a constant and OP0 was a SSA_NAME
defined by a type conversion. Replacing OP0 with RHS of the type conversion.
Doing so makes the conversion dead which helps subsequent passes. */
@@ -1305,7 +1317,8 @@ simplify_using_ranges::simplify_casted_compare (tree_code
&, tree &op0, tree &op
if (TREE_CODE (innerop) == SSA_NAME
&& !POINTER_TYPE_P (TREE_TYPE (innerop))
&& !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop)
- && desired_pro_or_demotion_p (TREE_TYPE (innerop), TREE_TYPE (op0)))
+ && desired_pro_or_demotion_p (TREE_TYPE (innerop), TREE_TYPE (op0))
+ && !next_use_is_phi (op0))
{
value_range vr;
--
2.17.1
