[gcc r12-3574] sparc: Skip all empty assembly statements

[gcc r12-3574] sparc: Skip all empty assembly statements

[Daniel Hellstrom]

https://gcc.gnu.org/g:6d0c97b19a306cf192ef9e8d0222635192dbc710

commit r12-3574-g6d0c97b19a306cf192ef9e8d0222635192dbc710
Author: Daniel Cederman <cederman@gaisler.com>
Date:   Fri Oct 16 09:12:30 2020 +0200

    sparc: Skip all empty assembly statements
    
    This version detects multiple empty assembly statements in a row and also
    detects non-memory barrier empty assembly statements (__asm__("")). It
    can be used instead of next_active_insn().
    
    gcc/ChangeLog:
    
            * config/sparc/sparc.c (next_active_non_empty_insn): New function
            that returns next active non empty assembly instruction.
            (sparc_do_work_around_errata): Use new function.

Diff:
---
 gcc/config/sparc/sparc.c | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c
index 49cee356a83..94061e111bd 100644
--- a/gcc/config/sparc/sparc.c
+++ b/gcc/config/sparc/sparc.c
@@ -1094,6 +1094,24 @@ load_insn_p (rtx_insn *insn)
    && GET_CODE (PATTERN (INSN)) != USE					\
    && GET_CODE (PATTERN (INSN)) != CLOBBER)
 
+rtx_insn *
+next_active_non_empty_insn (rtx_insn *insn)
+{
+  insn = next_active_insn (insn);
+
+  while (insn
+	 && (GET_CODE (PATTERN (insn)) == UNSPEC_VOLATILE
+	     || GET_CODE (PATTERN (insn)) == ASM_INPUT
+	     || (USEFUL_INSN_P (insn)
+		 && (asm_noperands (PATTERN (insn)) >= 0)
+		 && !strcmp (decode_asm_operands (PATTERN (insn),
+						  NULL, NULL, NULL,
+						  NULL, NULL), ""))))
+    insn = next_active_insn (insn);
+
+  return insn;
+}
+
 static unsigned int
 sparc_do_work_around_errata (void)
 {
@@ -1151,7 +1169,7 @@ sparc_do_work_around_errata (void)
 		emit_insn_before (gen_nop (), target);
 	    }
 
-	  next = next_active_insn (insn);
+	  next = next_active_non_empty_insn (insn);
 	  if (!next)
 	    break;
 
@@ -1254,23 +1272,12 @@ sparc_do_work_around_errata (void)
 	  rtx_insn *after;
 	  int i;
 
-	  next = next_active_insn (insn);
+	  next = next_active_non_empty_insn (insn);
 	  if (!next)
 	    break;
 
 	  for (after = next, i = 0; i < 2; i++)
 	    {
-	      /* Skip empty assembly statements.  */
-	      if ((GET_CODE (PATTERN (after)) == UNSPEC_VOLATILE)
-		  || (USEFUL_INSN_P (after)
-		      && (asm_noperands (PATTERN (after))>=0)
-		      && !strcmp (decode_asm_operands (PATTERN (after),
-						       NULL, NULL, NULL,
-						       NULL, NULL), "")))
-		after = next_active_insn (after);
-	      if (!after)
-		break;
-
 	      /* If the insn is a branch, then it cannot be problematic.  */
 	      if (!NONJUMP_INSN_P (after)
 		  || GET_CODE (PATTERN (after)) == SEQUENCE)
@@ -1295,7 +1302,7 @@ sparc_do_work_around_errata (void)
 		      && (MEM_P (SET_DEST (set)) || mem_ref (SET_SRC (set))))
 		    break;
 
-		  after = next_active_insn (after);
+		  after = next_active_non_empty_insn (after);
 		  if (!after)
 		    break;
 		}