vect: Fold LEN_{LOAD,STORE} if it's for the whole vector [PR107412]

As the test case in PR107412 shows, we can fold IFN .LEN_{LOAD,
STORE} into normal vector load/store if the given length is known
to be equal to the length of the whole vector.  It would help to
improve overall cycles as normally the latency of vector access
with length in bytes is bigger than normal vector access, and it
also saves the preparation for length if constant length can not
be encoded into instruction (such as on power).

	PR tree-optimization/107412

gcc/ChangeLog:

	* gimple-fold.cc (gimple_fold_mask_load_store_mem_ref): Rename to ...
	(gimple_fold_partial_load_store_mem_ref): ... this, add one parameter
	mask_p indicating it's for mask or length, and add some handlings for
	IFN LEN_{LOAD,STORE}.
	(gimple_fold_mask_load): Rename to ...
	(gimple_fold_partial_load): ... this, add one parameter mask_p.
	(gimple_fold_mask_store): Rename to ...
	(gimple_fold_partial_store): ... this, add one parameter mask_p.
	(gimple_fold_call): Add the handlings for IFN LEN_{LOAD,STORE},
	and adjust calls on gimple_fold_mask_load_store_mem_ref to
	gimple_fold_partial_load_store_mem_ref.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr107412.c: New test.
	* gcc.target/powerpc/p9-vec-length-epil-8.c: Adjust scan times for
	folded LEN_LOAD.

diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index 9055cd8..410544c 100644 (file)
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -5370,19 +5370,39 @@ arith_overflowed_p (enum tree_code code, const_tree type,
   return wi::min_precision (wres, sign) > TYPE_PRECISION (type);
 }
 
-/* If IFN_MASK_LOAD/STORE call CALL is unconditional, return a MEM_REF
+/* If IFN_{MASK,LEN}_LOAD/STORE call CALL is unconditional, return a MEM_REF
    for the memory it references, otherwise return null.  VECTYPE is the
-   type of the memory vector.  */
+   type of the memory vector.  MASK_P indicates it's for MASK if true,
+   otherwise it's for LEN.  */
 
 static tree
-gimple_fold_mask_load_store_mem_ref (gcall *call, tree vectype)
+gimple_fold_partial_load_store_mem_ref (gcall *call, tree vectype, bool mask_p)
 {
   tree ptr = gimple_call_arg (call, 0);
   tree alias_align = gimple_call_arg (call, 1);
-  tree mask = gimple_call_arg (call, 2);
-  if (!tree_fits_uhwi_p (alias_align) || !integer_all_onesp (mask))
+  if (!tree_fits_uhwi_p (alias_align))
     return NULL_TREE;
 
+  if (mask_p)
+    {
+      tree mask = gimple_call_arg (call, 2);
+      if (!integer_all_onesp (mask))
+       return NULL_TREE;
+    } else {
+      tree basic_len = gimple_call_arg (call, 2);
+      if (!tree_fits_uhwi_p (basic_len))
+       return NULL_TREE;
+      unsigned int nargs = gimple_call_num_args (call);
+      tree bias = gimple_call_arg (call, nargs - 1);
+      gcc_assert (tree_fits_uhwi_p (bias));
+      tree biased_len = int_const_binop (MINUS_EXPR, basic_len, bias);
+      unsigned int len = tree_to_uhwi (biased_len);
+      unsigned int vect_len
+       = GET_MODE_SIZE (TYPE_MODE (vectype)).to_constant ();
+      if (vect_len != len)
+       return NULL_TREE;
+    }
+
   unsigned HOST_WIDE_INT align = tree_to_uhwi (alias_align);
   if (TYPE_ALIGN (vectype) != align)
     vectype = build_aligned_type (vectype, align);
@@ -5390,16 +5410,18 @@ gimple_fold_mask_load_store_mem_ref (gcall *call, tree vectype)
   return fold_build2 (MEM_REF, vectype, ptr, offset);
 }
 
-/* Try to fold IFN_MASK_LOAD call CALL.  Return true on success.  */
+/* Try to fold IFN_{MASK,LEN}_LOAD call CALL.  Return true on success.
+   MASK_P indicates it's for MASK if true, otherwise it's for LEN.  */
 
 static bool
-gimple_fold_mask_load (gimple_stmt_iterator *gsi, gcall *call)
+gimple_fold_partial_load (gimple_stmt_iterator *gsi, gcall *call, bool mask_p)
 {
   tree lhs = gimple_call_lhs (call);
   if (!lhs)
     return false;
 
-  if (tree rhs = gimple_fold_mask_load_store_mem_ref (call, TREE_TYPE (lhs)))
+  if (tree rhs
+      = gimple_fold_partial_load_store_mem_ref (call, TREE_TYPE (lhs), mask_p))
     {
       gassign *new_stmt = gimple_build_assign (lhs, rhs);
       gimple_set_location (new_stmt, gimple_location (call));
@@ -5410,13 +5432,16 @@ gimple_fold_mask_load (gimple_stmt_iterator *gsi, gcall *call)
   return false;
 }
 
-/* Try to fold IFN_MASK_STORE call CALL.  Return true on success.  */
+/* Try to fold IFN_{MASK,LEN}_STORE call CALL.  Return true on success.
+   MASK_P indicates it's for MASK if true, otherwise it's for LEN.  */
 
 static bool
-gimple_fold_mask_store (gimple_stmt_iterator *gsi, gcall *call)
+gimple_fold_partial_store (gimple_stmt_iterator *gsi, gcall *call,
+                          bool mask_p)
 {
   tree rhs = gimple_call_arg (call, 3);
-  if (tree lhs = gimple_fold_mask_load_store_mem_ref (call, TREE_TYPE (rhs)))
+  if (tree lhs
+      = gimple_fold_partial_load_store_mem_ref (call, TREE_TYPE (rhs), mask_p))
     {
       gassign *new_stmt = gimple_build_assign (lhs, rhs);
       gimple_set_location (new_stmt, gimple_location (call));
@@ -5635,10 +5660,16 @@ gimple_fold_call (gimple_stmt_iterator *gsi, bool inplace)
          cplx_result = true;
          break;
        case IFN_MASK_LOAD:
-         changed |= gimple_fold_mask_load (gsi, stmt);
+         changed |= gimple_fold_partial_load (gsi, stmt, true);
          break;
        case IFN_MASK_STORE:
-         changed |= gimple_fold_mask_store (gsi, stmt);
+         changed |= gimple_fold_partial_store (gsi, stmt, true);
+         break;
+       case IFN_LEN_LOAD:
+         changed |= gimple_fold_partial_load (gsi, stmt, false);
+         break;
+       case IFN_LEN_STORE:
+         changed |= gimple_fold_partial_store (gsi, stmt, false);
          break;
        default:
          break;

diff --git a/gcc/testsuite/gcc.target/powerpc/p9-vec-length-epil-8.c b/gcc/testsuite/gcc.target/powerpc/p9-vec-length-epil-8.c
index 961df0d..8b9c910 100644 (file)
--- a/gcc/testsuite/gcc.target/powerpc/p9-vec-length-epil-8.c
+++ b/gcc/testsuite/gcc.target/powerpc/p9-vec-length-epil-8.c
@@ -8,5 +8,5 @@
 
 #include "p9-vec-length-8.h"
 
-/* { dg-final { scan-assembler-times {\mlxvl\M} 21 } } */
+/* { dg-final { scan-assembler-times {\mlxvl\M} 16 } } */
 /* { dg-final { scan-assembler-times {\mstxvl\M} 7 } } */

diff --git a/gcc/testsuite/gcc.target/powerpc/pr107412.c b/gcc/testsuite/gcc.target/powerpc/pr107412.c
new file mode 100644 (file)
index 0000000..4526ea8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr107412.c
@@ -0,0 +1,19 @@
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-mdejagnu-cpu=power9 -O2 -ftree-vectorize -fno-vect-cost-model -funroll-loops -fno-tree-loop-distribute-patterns --param vect-partial-vector-usage=2 -fdump-tree-optimized" } */
+
+/* Verify there is only one IFN call LEN_LOAD and IFN_STORE separately.  */
+
+#define N 16
+int src[N];
+int dest[N];
+
+void
+foo ()
+{
+  for (int i = 0; i < (N - 1); i++)
+    dest[i] = src[i];
+}
+
+/* { dg-final { scan-tree-dump-times {\mLEN_LOAD\M} 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times {\mLEN_STORE\M} 1 "optimized" } } */