[PATCH] i386: Skip DF_REF_INSN if DF_REF_INSN_INFO is false

[H.J. Lu]

We should check DF_REF_INSN_INFO before accessing DF_REF_INSN.

OK for trunk?

H.J.
---
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.
---
 gcc/config/i386/i386.c                  |  7 +++++--
 gcc/testsuite/gcc.target/i386/pr82673.c | 12 ++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr82673.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index b86504378ae..25c898866e2 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -12694,10 +12694,13 @@ 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);
 
diff --git a/gcc/testsuite/gcc.target/i386/pr82673.c 
b/gcc/testsuite/gcc.target/i386/pr82673.c
new file mode 100644
index 00000000000..cff4b34535b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr82673.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O0 -fno-omit-frame-pointer 
-fvar-tracking-assignments-toggle" } */
+
+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" } */
-- 
2.13.6