i386: Skip DF_REF_INSN if DF_REF_INSN_INFO is false

We should check DF_REF_INSN_INFO before accessing DF_REF_INSN.

gcc/

	PR target/82673
	* config/i386/i386.c (ix86_finalize_stack_frame_flags): Skip
	DF_REF_INSN if DF_REF_INSN_INFO is false.

gcc/testsuite/

	PR target/82673
	* gcc.target/i386/pr82673.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@254013 138bc75d-0d04-0410-961f-82ee72b054a4

Author: hjl

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2017-10-23  H.J. Lu  <[email protected]>
+
+	PR target/82673
+	* config/i386/i386.c (ix86_finalize_stack_frame_flags): Skip
+	DF_REF_INSN if DF_REF_INSN_INFO is false.
+
 2017-10-23  Jan Hubicka  <[email protected]>
 
 	* i386.c (dimode_scalar_chain::compute_convert_gain): Use

gcc/config/i386/i386.c

@@ -12692,10 +12692,13 @@ ix86_finalize_stack_frame_flags (void)
 	      for (ref = DF_REG_USE_CHAIN (HARD_FRAME_POINTER_REGNUM);
 		   ref; ref = next)
 		{
-		  rtx_insn *insn = DF_REF_INSN (ref);
+		  next = DF_REF_NEXT_REG (ref);
+		  if (!DF_REF_INSN_INFO (ref))
+		    continue;
+
 		  /* Make sure the next ref is for a different instruction,
 		     so that we're not affected by the rescan.  */
-		  next = DF_REF_NEXT_REG (ref);
+		  rtx_insn *insn = DF_REF_INSN (ref);
 		  while (next && DF_REF_INSN (next) == insn)
 		    next = DF_REF_NEXT_REG (next);
 

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2017-10-23  H.J. Lu  <[email protected]>
+
+	PR target/82673
+	* gcc.target/i386/pr82673.c: New test.
+
 2017-10-23  Jakub Jelinek  <[email protected]>
 
 	* lib/scanasm.exp (dg-function-on-line): Accept optional column info.

gcc/testsuite/gcc.target/i386/pr82673.c

@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O0 -fno-omit-frame-pointer -fvar-tracking-assignments" } */
+
+register long *B asm ("ebp");
+
+long y = 20;
+
+void
+bar (void) /* { dg-error "frame pointer required, but reserved" } */
+{
+  B = &y;
+} /* { dg-error "bp cannot be used in asm here" } */