So when I wrote this code I limited the middle store to only
be a SSA name. This is too limited and we reject constants which the full
cselim can handle just fine. This extends the check to support gimple
min invariants too.
Also the check for clobber is changed to be instead to be ssa name/min invariant
instead. This will still reject clobbers correctly and support what we can
support
here.
This was found while looking into std::optional code generation in some cases.
Bootstrapped and tested on x86_64-linux-gnu.
PR tree-optimization/127052
gcc/ChangeLog:
* tree-ssa-phiopt.cc (cond_store_replacement_limited): Extend check
to support gimple min invariants.
Change check for non clobbers to be ssa name or min invariant.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/cselim-6.c: New test.
* gcc.dg/tree-ssa/cselim-7.c: New test.
Signed-off-by: Andrea Pinski <[email protected]>
---
gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c | 17 +++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c | 18 ++++++++++++++++++
gcc/tree-ssa-phiopt.cc | 10 ++++++----
3 files changed, 41 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c
b/gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c
new file mode 100644
index 00000000000..54d1446ecd7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
+/* PR tree-optimization/127052 */
+
+int *sink(int*);
+void f(int a, int c, int d, int *e)
+{
+ e = sink(&a);
+ a = d;
+ c = *e;
+ c += a;
+ if (c)
+ a = 0;
+ sink(&a);
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c
b/gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c
new file mode 100644
index 00000000000..8db89c24b56
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
+/* PR tree-optimization/127052 */
+
+void sink(int*);
+
+int f(int b)
+{
+ int a;
+ sink(&a);
+ a = b;
+ if (a)
+ a = 0;
+ return a;
+}
+
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index f8dbd26abc1..ddb2e353cf4 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -3655,7 +3655,8 @@ cond_store_replacement_limited (basic_block middle_bb,
basic_block join_bb,
&& !DECL_P (lhs))
|| !is_gimple_reg_type (TREE_TYPE (lhs)))
return false;
- if (TREE_CODE (rhs) != SSA_NAME)
+ if (TREE_CODE (rhs) != SSA_NAME
+ && !is_gimple_min_invariant (rhs))
return false;
/* Three cases that can be handled:
@@ -3678,11 +3679,12 @@ cond_store_replacement_limited (basic_block middle_bb,
basic_block join_bb,
tree beforelhs = gimple_assign_lhs (vdef_before);
/* Only allow the store to be right before the condition. */
if (gimple_bb (vdef_before) == cond_bb
- /* This can't be a clobber */
- && !gimple_clobber_p (vdef_before)
/* An exact match is only supported.
FIXME: Allow for clique/base mismatch? */
- && operand_equal_p (lhs, beforelhs))
+ && operand_equal_p (lhs, beforelhs)
+ // The rhs needs to be a ssa name or a min invariant.
+ && (TREE_CODE (gimple_assign_rhs1 (vdef_before)) == SSA_NAME
+ || is_gimple_min_invariant (gimple_assign_rhs1 (vdef_before))))
{
/* The vuse of the of store in the middle should be also
the entry in the phi for the other edge. */
--
2.43.0
