* flow.c (mark_used_reg): Use reg_set_p to determine if a register

        was modified in the current insn.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@33030 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 12 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 87194541bed..97c0cfa819f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2000-04-08  Richard Henderson  <rth@cygnus.com>
+
+	* flow.c (mark_used_reg): Use reg_set_p to determine if a register
+	was modified in the current insn.
+
 2000-04-08  Richard Earnshaw (rearnsha@arm.com)
 
 	* arm/thumb.md: Delete.
diff --git a/gcc/flow.c b/gcc/flow.c
index ea386232ea7..e900617c9b2 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -4520,11 +4520,17 @@ mark_used_reg (pbi, new_live, reg, cond, insn)
 
   /* Record and count the insns in which a reg dies.  If it is used in
      this insn and was dead below the insn then it dies in this insn.
+
      If it was set in this insn, we do not make a REG_DEAD note;
-     likewise if we already made such a note.  */
+     likewise if we already made such a note.  Recall that dead_or_set_p
+     checks for complete overlap, and thus is not suitable for the first
+     case.  But it does handle the existing note case.  Also recall that
+     reg_set_p, when presented with the complete insn, will try to infer
+     things about a call_insn that we do not wish.  */
 
   if ((pbi->flags & PROP_DEATH_NOTES)
       && some_was_dead
+      && ! reg_set_p (reg, PATTERN (insn))
       && ! dead_or_set_p (insn, reg))
     {
       int n;