From 0c016888ffd569c4b70722cf7df2efcc003f397b Mon Sep 17 00:00:00 2001
From: "Vladimir N. Makarov" <vmakarov@redhat.com>
Date: Fri, 18 Mar 2022 14:23:40 -0400
Subject: [PATCH] [PR104961] LRA: split hard reg for reload pseudo with
 clobber.

Splitting hard register live range did not work for subreg of a
multi-reg reload pseudo.  Reload insns for such pseudo contain clobber
of the pseudo and splitting did not take this into account.  The patch
fixes it.

gcc/ChangeLog:

	PR rtl-optimization/104961
	* lra-assigns.cc (find_reload_regno_insns): Process reload pseudo clobber.

gcc/testsuite/ChangeLog:

	PR rtl-optimization/104961
	* gcc.target/i386/pr104961.c: New.
---
 gcc/lra-assigns.cc                       | 33 ++++++++++++++++++--------------
 gcc/testsuite/gcc.target/i386/pr104961.c | 15 +++++++++++++++
 2 files changed, 34 insertions(+), 14 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr104961.c

diff --git a/gcc/lra-assigns.cc b/gcc/lra-assigns.cc
index ab3a6e6..af30a67 100644
--- a/gcc/lra-assigns.cc
+++ b/gcc/lra-assigns.cc
@@ -1706,7 +1706,8 @@ find_reload_regno_insns (int regno, rtx_insn * &start, rtx_insn * &finish)
 {
   unsigned int uid;
   bitmap_iterator bi;
-  int n = 0;
+  int insns_num = 0;
+  bool clobber_p = false;
   rtx_insn *prev_insn, *next_insn;
   rtx_insn *start_insn = NULL, *first_insn = NULL, *second_insn = NULL;
   
@@ -1714,28 +1715,32 @@ find_reload_regno_insns (int regno, rtx_insn * &start, rtx_insn * &finish)
     {
       if (start_insn == NULL)
 	start_insn = lra_insn_recog_data[uid]->insn;
-      n++;
+      if (GET_CODE (PATTERN (lra_insn_recog_data[uid]->insn)) == CLOBBER)
+	clobber_p = true;
+      else
+	insns_num++;
     }
-  /* For reload pseudo we should have at most 3 insns referring for
+  /* For reload pseudo we should have at most 3 insns besides clobber referring for
      it: input/output reload insns and the original insn.  */
-  if (n > 3)
+  if (insns_num > 3)
     return false;
-  if (n > 1)
+  if (clobber_p)
+    insns_num++;
+  if (insns_num > 1)
     {
       for (prev_insn = PREV_INSN (start_insn),
 	     next_insn = NEXT_INSN (start_insn);
-	   n != 1 && (prev_insn != NULL || next_insn != NULL); )
+	   insns_num != 1 && (prev_insn != NULL || next_insn != NULL); )
 	{
-	  if (prev_insn != NULL && first_insn == NULL)
+	  if (prev_insn != NULL)
 	    {
-	      if (! bitmap_bit_p (&lra_reg_info[regno].insn_bitmap,
-				  INSN_UID (prev_insn)))
-		prev_insn = PREV_INSN (prev_insn);
-	      else
+	      if (bitmap_bit_p (&lra_reg_info[regno].insn_bitmap,
+				INSN_UID (prev_insn)))
 		{
 		  first_insn = prev_insn;
-		  n--;
+		  insns_num--;
 		}
+		prev_insn = PREV_INSN (prev_insn);
 	    }
 	  if (next_insn != NULL && second_insn == NULL)
 	    {
@@ -1745,11 +1750,11 @@ find_reload_regno_insns (int regno, rtx_insn * &start, rtx_insn * &finish)
 	      else
 		{
 		  second_insn = next_insn;
-		  n--;
+		  insns_num--;
 		}
 	    }
 	}
-      if (n > 1)
+      if (insns_num > 1)
 	return false;
     }
   start = first_insn != NULL ? first_insn : start_insn;
diff --git a/gcc/testsuite/gcc.target/i386/pr104961.c b/gcc/testsuite/gcc.target/i386/pr104961.c
new file mode 100644
index 0000000..11ea95a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr104961.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-Og" } */
+
+__int128 i;
+
+void bar (int);
+
+void
+foo (int a, char b, _Complex unsigned char c)
+{
+  __int128 j = i * i;
+  c -= 1;
+  bar (j);
+  bar (__imag__ c);
+}
-- 
2.7.4