[PATCH] by_pieces: Properly set m_max_size in op_by_pieces

["H.J. Lu" <hjl.tools@gmail.com>]

1. Update x86 STORE_MAX_PIECES to use OImode and XImode only if inter-unit
move is enabled since x86 uses vec_duplicate, which is enabled only when
inter-unit move is enabled, to implement store_by_pieces.
2. Update op_by_pieces_d::op_by_pieces_d to set m_max_size to
STORE_MAX_PIECES for store_by_pieces and to COMPARE_MAX_PIECES for
compare_by_pieces.

gcc/

	PR target/101742
	* expr.c (op_by_pieces_d::op_by_pieces_d): Set m_max_size to
	STORE_MAX_PIECES for store_by_pieces and to COMPARE_MAX_PIECES
	for compare_by_pieces.
	* config/i386/i386.h (STORE_MAX_PIECES): Use OImode and XImode
	only if TARGET_INTER_UNIT_MOVES_TO_VEC is true.

gcc/testsuite/

	PR target/101742
	* gcc.target/i386/pr101742a.c: New test.
	* gcc.target/i386/pr101742b.c: Likewise.
---
 gcc/config/i386/i386.h                    | 20 +++++++++++---------
 gcc/expr.c                                |  6 +++++-
 gcc/testsuite/gcc.target/i386/pr101742a.c | 16 ++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr101742b.c |  4 ++++
 4 files changed, 36 insertions(+), 10 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr101742a.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr101742b.c

diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index bed9cd9da18..9b416abd5f4 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -1783,15 +1783,17 @@ typedef struct ix86_args {
 /* STORE_MAX_PIECES is the number of bytes at a time that we can
    store efficiently.  */
 #define STORE_MAX_PIECES \
-  ((TARGET_AVX512F && !TARGET_PREFER_AVX256) \
-   ? 64 \
-   : ((TARGET_AVX \
-       && !TARGET_PREFER_AVX128 \
-       && !TARGET_AVX256_SPLIT_UNALIGNED_STORE) \
-      ? 32 \
-      : ((TARGET_SSE2 \
-	  && TARGET_SSE_UNALIGNED_STORE_OPTIMAL) \
-	 ? 16 : UNITS_PER_WORD)))
+  (TARGET_INTER_UNIT_MOVES_TO_VEC \
+   ? ((TARGET_AVX512F && !TARGET_PREFER_AVX256) \
+      ? 64 \
+      : ((TARGET_AVX \
+	  && !TARGET_PREFER_AVX128 \
+	  && !TARGET_AVX256_SPLIT_UNALIGNED_STORE) \
+	  ? 32 \
+	  : ((TARGET_SSE2 \
+	      && TARGET_SSE_UNALIGNED_STORE_OPTIMAL) \
+	      ? 16 : UNITS_PER_WORD))) \
+   : UNITS_PER_WORD)
 
 /* If a memory-to-memory move would take MOVE_RATIO or more simple
    move-instruction pairs, we will do a cpymem or libcall instead.
diff --git a/gcc/expr.c b/gcc/expr.c
index b65cfcfdcd1..2964b38b9a5 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1131,7 +1131,11 @@ op_by_pieces_d::op_by_pieces_d (rtx to, bool to_load,
 				bool qi_vector_mode)
   : m_to (to, to_load, NULL, NULL),
     m_from (from, from_load, from_cfn, from_cfn_data),
-    m_len (len), m_max_size (MOVE_MAX_PIECES + 1),
+    m_len (len),
+    m_max_size (((!to_load && from == nullptr)
+		 ? STORE_MAX_PIECES
+		 : (from_cfn != nullptr
+		    ? COMPARE_MAX_PIECES : MOVE_MAX_PIECES)) + 1),
     m_push (push), m_qi_vector_mode (qi_vector_mode)
 {
   int toi = m_to.get_addr_inc ();
diff --git a/gcc/testsuite/gcc.target/i386/pr101742a.c b/gcc/testsuite/gcc.target/i386/pr101742a.c
new file mode 100644
index 00000000000..67ea40587dd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr101742a.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3 -mtune=nano-x2" } */
+
+int n2;
+
+__attribute__ ((simd)) char
+w7 (void)
+{
+  short int xb = n2;
+  int qp;
+
+  for (qp = 0; qp < 2; ++qp)
+    xb = xb < 1;
+
+  return xb;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr101742b.c b/gcc/testsuite/gcc.target/i386/pr101742b.c
new file mode 100644
index 00000000000..ba19064077b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr101742b.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3 -mtune=nano-x2 -mtune-ctrl=sse_unaligned_store_optimal" } */
+
+#include "pr101742a.c"
-- 
2.31.1