From 4759383245ac97a5c83c0272f0a831f2a26ea5c1 Mon Sep 17 00:00:00 2001
From: Jiufu Guo <guojiufu@linux.ibm.com>
Date: Tue, 19 Dec 2023 13:03:06 +0800
Subject: [PATCH] treat argp-based mem as frame related in dse

The issue mentioned in PR112525 would be able to be handled by
updating dse.cc to treat arg_pointer_rtx similarly with frame_pointer_rtx.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30271#c10 also mentioned
this idea.

And arpg area may be used to pass argument to callee. So, it would
be needed to check if call insns are using that mem.

	PR rtl-optimization/112525
	PR target/30271

gcc/ChangeLog:

	* dse.cc (get_group_info): Add arg_pointer_rtx as frame_related.
	(check_mem_read_rtx): Add parameter to indicate if it is checking mem
	for call insn.
	(scan_insn): Add mem checking on call usage.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr112525.c: New test.
	* gcc.target/powerpc/pr30271.c: New test.
---
 gcc/dse.cc                                  | 17 +++++++++++++----
 gcc/testsuite/gcc.target/powerpc/pr112525.c | 15 +++++++++++++++
 gcc/testsuite/gcc.target/powerpc/pr30271.c  | 15 +++++++++++++++
 3 files changed, 43 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr112525.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr30271.c

diff --git a/gcc/dse.cc b/gcc/dse.cc
index 40c4c29d07e0..b98b47fff608 100644
--- a/gcc/dse.cc
+++ b/gcc/dse.cc
@@ -682,7 +682,8 @@ get_group_info (rtx base)
       gi->group_kill = BITMAP_ALLOC (&dse_bitmap_obstack);
       gi->process_globally = false;
       gi->frame_related =
-	(base == frame_pointer_rtx) || (base == hard_frame_pointer_rtx);
+	(base == frame_pointer_rtx) || (base == hard_frame_pointer_rtx)
+	|| (base == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]);
       gi->offset_map_size_n = 0;
       gi->offset_map_size_p = 0;
       gi->offset_map_n = NULL;
@@ -2164,7 +2165,7 @@ replace_read (store_info *store_info, insn_info_t store_insn,
    be active.  */
 
 static void
-check_mem_read_rtx (rtx *loc, bb_info_t bb_info)
+check_mem_read_rtx (rtx *loc, bb_info_t bb_info, bool used_in_call = false)
 {
   rtx mem = *loc, mem_addr;
   insn_info_t insn_info;
@@ -2309,7 +2310,8 @@ check_mem_read_rtx (rtx *loc, bb_info_t bb_info)
 		 stored, rewrite the read.  */
 	      else
 		{
-		  if (store_info->rhs
+		  if (!used_in_call
+		      && store_info->rhs
 		      && known_subrange_p (offset, width, store_info->offset,
 					   store_info->width)
 		      && all_positions_needed_p (store_info,
@@ -2375,7 +2377,8 @@ check_mem_read_rtx (rtx *loc, bb_info_t bb_info)
 
 	  /* If this read is just reading back something that we just
 	     stored, rewrite the read.  */
-	  if (store_info->rhs
+	  if (!used_in_call
+	      && store_info->rhs
 	      && store_info->group_id == -1
 	      && store_info->cse_base == base
 	      && known_subrange_p (offset, width, store_info->offset,
@@ -2657,6 +2660,12 @@ scan_insn (bb_info_t bb_info, rtx_insn *insn, int max_active_local_stores)
            that is not relative to the frame.  */
         add_non_frame_wild_read (bb_info);
 
+      for (rtx link = CALL_INSN_FUNCTION_USAGE (insn);
+	   link != NULL_RTX;
+	   link = XEXP (link, 1))
+	if (GET_CODE (XEXP (link, 0)) == USE && MEM_P (XEXP (XEXP (link, 0),0)))
+	  check_mem_read_rtx (&XEXP (XEXP (link, 0),0), bb_info, true);
+
       return;
     }
 
diff --git a/gcc/testsuite/gcc.target/powerpc/pr112525.c b/gcc/testsuite/gcc.target/powerpc/pr112525.c
new file mode 100644
index 000000000000..428598188e7d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr112525.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O2" } */
+
+typedef struct teststruct
+{
+  double d;
+  int arr[15]; 
+} teststruct;
+
+void
+foo (teststruct p)
+{
+}
+
+/* { dg-final { scan-assembler-not {\mstd\M} } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr30271.c b/gcc/testsuite/gcc.target/powerpc/pr30271.c
new file mode 100644
index 000000000000..bddef039798e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr30271.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O3 -mstrict-align" } */
+
+struct SS
+{
+  int t, t1;
+};
+
+int
+f (struct SS b)
+{
+  return b.t + b.t1;
+}
+
+/* { dg-final { scan-assembler-not {\mstd\M} } } */
-- 
2.47.2