This patch implemented the optimization in PR 54346, which Merges
c = VEC_PERM_EXPR <a, b, VCST0>;
d = VEC_PERM_EXPR <c, c, VCST1>;
to
d = VEC_PERM_EXPR <a, b, NEW_VCST>;
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}
tree-ssa/forwprop-19.c fail to pass but I'm not sure whether it
is ok to removed it.
gcc/ChangeLog:
PR target/54346
* match.pd: Merge the index of VCST then generates the new vec_perm.
gcc/testsuite/ChangeLog:
PR target/54346
* gcc.dg/pr54346.c: New test.
Co-authored-by: liuhongt <hongtao....@intel.com>
---
gcc/match.pd | 41 ++++++++++++++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr54346.c | 13 +++++++++++
2 files changed, 54 insertions(+)
create mode 100755 gcc/testsuite/gcc.dg/pr54346.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 345bcb701a5..9219b0a10e1 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -8086,6 +8086,47 @@ and,
(minus (mult (vec_perm @1 @1 @3) @2) @4)))
+/* (PR54346) Merge
+ c = VEC_PERM_EXPR <a, b, VCST0>;
+ d = VEC_PERM_EXPR <c, c, VCST1>;
+ to
+ d = VEC_PERM_EXPR <a, b, NEW_VCST>; */
+
+(simplify
+ (vec_perm (vec_perm@0 @1 @2 VECTOR_CST@3) @0 VECTOR_CST@4)
+ (with
+ {
+ if(!TYPE_VECTOR_SUBPARTS (type).is_constant())
+ return NULL_TREE;
+
+ tree op0;
+ machine_mode result_mode = TYPE_MODE (type);
+ machine_mode op_mode = TYPE_MODE (TREE_TYPE (@1));
+ int nelts = TYPE_VECTOR_SUBPARTS (type).to_constant();
+ vec_perm_builder builder0;
+ vec_perm_builder builder1;
+ vec_perm_builder builder2 (nelts, nelts, 1);
+
+ if (!tree_to_vec_perm_builder (&builder0, @3)
+ || !tree_to_vec_perm_builder (&builder1, @4))
+ return NULL_TREE;
+
+ vec_perm_indices sel0 (builder0, 2, nelts);
+ vec_perm_indices sel1 (builder1, 1, nelts);
+
+ for (int i = 0; i < nelts; i++)
+ builder2.quick_push (sel0[sel1[i].to_constant()]);
+
+ vec_perm_indices sel2 (builder2, 2, nelts);
+
+ if (!can_vec_perm_const_p (result_mode, op_mode, sel2, false))
+ return NULL_TREE;
+
+ op0 = vec_perm_indices_to_tree (TREE_TYPE (@4), sel2);
+ }
+ (vec_perm @1 @2 { op0; })))
+
+
/* Match count trailing zeroes for simplify_count_trailing_zeroes in fwprop.
The canonical form is array[((x & -x) * C) >> SHIFT] where C is a magic
constant which when multiplied by a power of 2 contains a unique value
diff --git a/gcc/testsuite/gcc.dg/pr54346.c b/gcc/testsuite/gcc.dg/pr54346.c
new file mode 100755
index 00000000000..d87dc3a79a5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr54346.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-dse1" } */
+
+typedef int veci __attribute__ ((vector_size (4 * sizeof (int))));
+
+void fun (veci a, veci b, veci *i)
+{
+ veci c = __builtin_shuffle (a, b, __extension__ (veci) {1, 4, 2, 7});
+ *i = __builtin_shuffle (c, __extension__ (veci) { 7, 2, 1, 5 });
+}
+
+/* { dg-final { scan-tree-dump "VEC_PERM_EXPR.*{ 3, 6, 0, 0 }" "dse1" } } */
+/* { dg-final { scan-tree-dump-times "VEC_PERM_EXPR" 1 "dse1" } } */
\ No newline at end of file
--
2.18.2
