Fix reg-alloc error reported by Andreas Schwab to Trillian list.

	* config/ia64/ia64.c (find_gr_spill): Subtract frame_pointer_needed
	from 80 in try_locals code.
	(ia64_expand_prologue): Add comment pointing to find_gr_spill change.

From-SVN: r40447

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 88a11cdb55603e71b6247c2a5da8ce96fe766939..0fcf77fcd6392b67402957194e9df3fb818701b2 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2001-03-13  Jim Wilson  <wilson@redhat.com>
+
+       * config/ia64/ia64.c (find_gr_spill): Subtract frame_pointer_needed
+       from 80 in try_locals code.
+       (ia64_expand_prologue): Add comment pointing to find_gr_spill change.
+
 2001-03-13  Zack Weinberg  <zackw@stanford.edu>
 
        * aclocal.m4 (gcc_AC_COMPILE_CHECK_SIZEOF, gcc_AC_C_CHAR_BIT,

diff --git a/gcc/config/ia64/ia64.c b/gcc/config/ia64/ia64.c
index 2b72959bdbb7777e5237dbe08787658618832797..fb8a5847ec2fe728995c930ca7787005f70536b4 100644 (file)
--- a/gcc/config/ia64/ia64.c
+++ b/gcc/config/ia64/ia64.c
@@ -1214,7 +1214,10 @@ find_gr_spill (try_locals)
   if (try_locals)
     {
       regno = current_frame_info.n_local_regs;
-      if (regno < 80)
+      /* If there is a frame pointer, then we can't use loc79, because
+        that is HARD_FRAME_POINTER_REGNUM.  In particular, see the
+        reg_name switching code in ia64_expand_prologue.  */
+      if (regno < (80 - frame_pointer_needed))
        {
          current_frame_info.n_local_regs = regno + 1;
          return LOC_REG (0) + regno;
@@ -1874,6 +1877,10 @@ ia64_expand_prologue ()
   /* Set the frame pointer register name.  The regnum is logically loc79,
      but of course we'll not have allocated that many locals.  Rather than
      worrying about renumbering the existing rtxs, we adjust the name.  */
+  /* ??? This code means that we can never use one local register when
+     there is a frame pointer.  loc79 gets wasted in this case, as it is
+     renamed to a register that will never be used.  See also the try_locals
+     code in find_gr_spill.  */
   if (current_frame_info.reg_fp)
     {
       const char *tmp = reg_names[HARD_FRAME_POINTER_REGNUM];