reload1.c (elimination_effects): Use function_invariant_p instead of CONSTANT_P when...

        * reload1.c (elimination_effects): Use function_invariant_p
        instead of CONSTANT_P when considering register equivalences.

From-SVN: r47226

gcc/ChangeLog

+2001-11-20  Brad Kaiser  <bkaiser@acelink.net>
+ 
+	* reload1.c (elimination_effects): Use function_invariant_p
+	instead of CONSTANT_P when considering register equivalences.
+
 2001-11-20  David O'Brien  <obrien@FreeBSD.org>
 
 	* config.gcc: Add FreeBSD/PowerPC target.

gcc/reload1.c

@@ -2699,7 +2699,7 @@ elimination_effects (x, mem_mode)
 	}
       else if (reg_renumber[regno] < 0 && reg_equiv_constant
 	       && reg_equiv_constant[regno]
-	       && ! CONSTANT_P (reg_equiv_constant[regno]))
+	       && ! function_invariant_p (reg_equiv_constant[regno]))
 	elimination_effects (reg_equiv_constant[regno], mem_mode);
       return;
 

gcc/testsuite/gcc.dg/20011119-1.c

+/* Test for reload failing to eliminate from argp to sp.  */
+/* { dg-do run { target i?86-*-* } } */
+/* { dg-options "-O2 -fomit-frame-pointer" } */
+
+static int ustrsize (const char *s);
+static int (*ucwidth) (int c);
+static int (*ugetxc) (const char **s);
+static int (*usetc) (char *s, int c);
+
+char *ustrzcat(char *dest, int size, const char *src)
+{
+   int pos = ustrsize(dest);
+   int c;
+
+   size -= pos + ucwidth(0);
+
+   while ((c = ugetxc(&src)) != 0) {
+      size -= ucwidth(c);
+      if (size < 0)
+         break;
+
+      pos += usetc(dest+pos, c);
+   }
+
+   usetc(dest+pos, 0);
+
+   return dest;
+}
+
+static int __attribute__((noinline))
+ustrsize (const char *s)
+{
+  return 0;
+}
+
+static int
+ucwidth_ (int c)
+{
+  return 1;
+}
+
+static int
+ugetxc_ (const char **s)
+{
+  return '\0';
+}
+
+static int
+usetc_ (char *s, int c)
+{
+  return 1;
+}
+
+int
+main()
+{
+  ucwidth = ucwidth_;
+  ugetxc = ugetxc_;
+  usetc = usetc_;
+  
+  /* ??? It is impossible to explicitly modify the hard frame pointer.
+     This will run afoul of code in flow.c that declines to mark regs
+     in eliminate_regs in regs_ever_used.  Apparently, we have to wait
+     for reload to decide that it won't need a frame pointer before a
+     variable can be allocated to %ebp.
+
+     So save, restore, and clobber %ebp by hand.  */
+
+  asm ("pushl %%ebp\n\t"
+       "movl $-1, %%ebp\n\t"
+       "pushl $0\n\t"
+       "pushl $0\n\t"
+       "pushl $0\n\t"
+       "call %P0\n\t"
+       "addl $12, %%esp\n\t"
+       "popl %%ebp"
+       : : "i"(ustrzcat));
+
+  return 0;
+}