[PATCH] Don't flush all call_used_reg_set regs on call in var-tracking, just regs_invalidated_by_call (PR debug/43593)

[Jakub Jelinek]

Hi!

E.g. stack pointer and a bunch of other regs don't need to be
flushed in dataflow_set_clear_at_call and as the attached testcase
shows it helps debug info quality on both i?86 and x86-64 (also
hit several times on cc1/cc1plus itself).  SP etc. are in call_used_regs
just because it must include all fixed regs, aren't really call used
and we have a special regset for what we really want -
regs_invalidated_by_call.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2010-03-30  Jakub Jelinek  <jakub@redhat.com>

	PR debug/43593
	* var-tracking.c (dataflow_set_clear_at_call): Invalidate
	just regs_invalidated_by_call instead all call_used_reg_set
	registers.

	* gcc.dg/guality/pr43593.c: New test.

--- gcc/var-tracking.c.jj	2010-03-30 10:23:29.000000000 +0200
+++ gcc/var-tracking.c	2010-03-30 12:09:37.000000000 +0200
@@ -4255,7 +4255,7 @@ dataflow_set_clear_at_call (dataflow_set
   int r;
 
   for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
-    if (TEST_HARD_REG_BIT (call_used_reg_set, r))
+    if (TEST_HARD_REG_BIT (regs_invalidated_by_call, r))
       var_regno_delete (set, r);
 
   if (MAY_HAVE_DEBUG_INSNS)
--- gcc/testsuite/gcc.dg/guality/pr43593.c.jj	2010-03-30 22:02:14.000000000 +0200
+++ gcc/testsuite/gcc.dg/guality/pr43593.c	2010-03-30 22:08:21.000000000 +0200
@@ -0,0 +1,24 @@
+/* PR debug/43593 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+
+void __attribute__((noinline))
+bar (int *p)
+{
+  asm volatile ("" : : "r" (p) : "memory");
+}
+
+int __attribute__((noinline))
+foo (void)
+{
+  int i, *j = &i;
+  bar (j);
+  return 6 + i;	/* { dg-final { gdb-test 16 "j" "&i" } } */
+}
+
+int
+main (void)
+{
+  foo ();
+  return 0;
+}

	Jakub