[PATCH] rs6000: Preserve REG_EH_REGION when replacing load/store [PR106091]

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi,
 
As test case in PR106091 shows, rs6000 specific pass swaps
doesn't preserve the reg_note REG_EH_REGION when replacing
some load insn at the end of basic block, it causes the
flow info verification to fail unexpectedly.  Since memory
reference rtx may trap, this patch is to ensure we copy
REG_EH_REGION reg_note while replacing swapped aligned load
or store.

Bootstrapped and regtested on powerpc64-linux-gnu P7 & P8,
and powerpc64le-linux-gnu P9 & P10.

Richi, could you help to review this patch from a point view
of non-call-exceptions expert?

I'm going to install it if it looks good to you.  Thanks!

-----
	PR target/106091

gcc/ChangeLog:

	* config/rs6000/rs6000-p8swap.cc (replace_swapped_aligned_store): Copy
	REG_EH_REGION when replacing one store insn having it.
	(replace_swapped_aligned_load): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106091.c: New test.
---
 gcc/config/rs6000/rs6000-p8swap.cc          | 20 ++++++++++++++++++--
 gcc/testsuite/gcc.target/powerpc/pr106091.c | 15 +++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106091.c

diff --git a/gcc/config/rs6000/rs6000-p8swap.cc b/gcc/config/rs6000/rs6000-p8swap.cc
index 275702fee1b..19fbbfb67dc 100644
--- a/gcc/config/rs6000/rs6000-p8swap.cc
+++ b/gcc/config/rs6000/rs6000-p8swap.cc
@@ -1690,7 +1690,15 @@ replace_swapped_aligned_store (swap_web_entry *insn_entry,
   gcc_assert ((GET_CODE (new_body) == SET)
 	      && MEM_P (SET_DEST (new_body)));

-  set_block_for_insn (new_insn, BLOCK_FOR_INSN (store_insn));
+  basic_block bb = BLOCK_FOR_INSN (store_insn);
+  set_block_for_insn (new_insn, bb);
+  /* Handle REG_EH_REGION note.  */
+  if (cfun->can_throw_non_call_exceptions && BB_END (bb) == store_insn)
+    {
+      rtx note = find_reg_note (store_insn, REG_EH_REGION, NULL_RTX);
+      if (note)
+	add_reg_note (new_insn, REG_EH_REGION, XEXP (note, 0));
+    }
   df_insn_rescan (new_insn);

   df_insn_delete (store_insn);
@@ -1784,7 +1792,15 @@ replace_swapped_aligned_load (swap_web_entry *insn_entry, rtx swap_insn)
   gcc_assert ((GET_CODE (new_body) == SET)
 	      && MEM_P (SET_SRC (new_body)));

-  set_block_for_insn (new_insn, BLOCK_FOR_INSN (def_insn));
+  basic_block bb = BLOCK_FOR_INSN (def_insn);
+  set_block_for_insn (new_insn, bb);
+  /* Handle REG_EH_REGION note.  */
+  if (cfun->can_throw_non_call_exceptions && BB_END (bb) == def_insn)
+    {
+      rtx note = find_reg_note (def_insn, REG_EH_REGION, NULL_RTX);
+      if (note)
+	add_reg_note (new_insn, REG_EH_REGION, XEXP (note, 0));
+    }
   df_insn_rescan (new_insn);

   df_insn_delete (def_insn);
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106091.c b/gcc/testsuite/gcc.target/powerpc/pr106091.c
new file mode 100644
index 00000000000..61ce8cf4733
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106091.c
@@ -0,0 +1,15 @@
+/* { dg-options "-O -fnon-call-exceptions -fno-tree-dce -fno-tree-forwprop -w" } */
+
+/* Verify there is no ICE.  */
+
+typedef short __attribute__ ((__vector_size__ (64))) V;
+V v, w;
+
+inline V foo (V a, V b);
+
+V
+foo (V a, V b)
+{
+  b &= v < b;
+  return (V){foo (b, w)[3], (V){}[3]};
+}
--
2.25.1