add IFCVT_MODIFY macros for the MD file to tweak the conditional execution support.

From-SVN: r34386

gcc/ChangeLog

+Sat Jun  3 19:05:30 2000  Michael Meissner  <meissner@redhat.com>
+
+	* ifcvt (process_insns): If IFCVT_MODIFY_INSN is defined, call it
+	with the pattern to do machine dependent work.
+	(cond_exec_process_if_block): If IFCVT_MODIFY_TESTS is defined,
+	use it to modify the true/false tests used in conditional
+	execution.  If IFCVT_MODIFY_FINAL and IFCVT_MODIFY_CANCEL are
+	defined, invoke them if the conversion to conditional execution
+	was successful or not.
+
+	* tm.texi (IFCVT_MODIFY_TESTS): Document.
+	(IFCVT_MODIFY_INSN): Ditto.
+	(IFCVT_MODIFY_FINAL): Ditto.
+	(IFCVT_MODIFY_CANCEL): Ditto.
+
 Sat Jun  3 15:26:13 2000  Matt Kraai <kraai@alumni.carnegiemellon.edu>
 
 	* toplev.c (main): Fix misspellings of possibility and language.

gcc/ifcvt.c

@@ -207,6 +207,7 @@ cond_exec_process_insns (start, end, test, prob_val, mod_ok)
 {
   int must_be_last = FALSE;
   rtx insn;
+  rtx pattern;
 
   for (insn = start; ; insn = NEXT_INSN (insn))
     {
@@ -239,9 +240,20 @@ cond_exec_process_insns (start, end, test, prob_val, mod_ok)
 	}
 
       /* Now build the conditional form of the instruction.  */
+      pattern = PATTERN (insn);
+
+      /* If the machine needs to modify the insn being conditionally executed,
+         say for example to force a constant integer operand into a temp
+         register, do so here.  */
+#ifdef IFCVT_MODIFY_INSN
+      IFCVT_MODIFY_INSN (pattern, insn);
+      if (! pattern)
+	return FALSE;
+#endif
+
       validate_change (insn, &PATTERN (insn),
 		       gen_rtx_COND_EXEC (VOIDmode, copy_rtx (test),
-					  PATTERN (insn)), 1);
+					  pattern), 1);
 
       if (GET_CODE (insn) == CALL_INSN && prob_val)
 	validate_change (insn, &REG_NOTES (insn),
@@ -369,6 +381,17 @@ cond_exec_process_if_block (test_bb, then_bb, else_bb, join_bb)
 			       GET_MODE (true_expr), XEXP (true_expr, 0),
 			       XEXP (true_expr, 1));
 
+#ifdef IFCVT_MODIFY_TESTS
+  /* If the machine description needs to modify the tests, such as setting a
+     conditional execution register from a comparison, it can do so here.  */
+  IFCVT_MODIFY_TESTS (true_expr, false_expr, test_bb, then_bb, else_bb,
+		      join_bb);
+
+  /* See if the conversion failed */
+  if (!true_expr || !false_expr)
+    goto fail;
+#endif
+
   true_prob_val = find_reg_note (test_bb->end, REG_BR_PROB, NULL_RTX);
   if (true_prob_val)
     {
@@ -398,6 +421,11 @@ cond_exec_process_if_block (test_bb, then_bb, else_bb, join_bb)
   if (! apply_change_group ())
     return FALSE;
 
+#ifdef IFCVT_MODIFY_FINAL
+  /* Do any machine dependent final modifications */
+  IFCVT_MODIFY_FINAL (test_bb, then_bb, else_bb, join_bb);
+#endif
+
   /* Conversion succeeded.  */
   if (rtl_dump_file)
     fprintf (rtl_dump_file, "%d insn%s converted to conditional execution.\n",
@@ -408,6 +436,11 @@ cond_exec_process_if_block (test_bb, then_bb, else_bb, join_bb)
   return TRUE;
 
  fail:
+#ifdef IFCVT_MODIFY_CANCEL
+  /* Cancel any machine dependent changes.  */
+  IFCVT_MODIFY_CANCEL (test_bb, then_bb, else_bb, join_bb);
+#endif
+
   cancel_changes (0);
   return FALSE;
 }

gcc/tm.texi

@@ -7973,4 +7973,29 @@ A C expression for the maximum number of instructions to execute via
 conditional execution instructions instead of a branch.  A value of
 @code{BRANCH_COST}+1 is the default if the machine does not use cc0, and
 1 if it does use cc0.
+
+@findex IFCVT_MODIFY_TESTS
+@item IFCVT_MODIFY_TESTS
+A C expression to modify the tests in @code{TRUE_EXPR}, and
+@code{FALSE_EXPPR} for use in converting insns in @code{TEST_BB},
+@code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB} basic blocks to
+conditional execution.  Set either @code{TRUE_EXPR} or @code{FALSE_EXPR}
+to a null pointer if the tests cannot be converted.
+
+@findex IFCVT_MODIFY_INSN
+@item IFCVT_MODIFY_INSN
+A C expression to modify the @code{PATTERN} of an @code{INSN} that is to
+be converted to conditional execution format.
+
+@findex IFCVT_MODIFY_FINAL
+@item IFCVT_MODIFY_FINAL
+A C expression to perform any final machine dependent modifications in
+converting code to conditional execution in the basic blocks
+@code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
+
+@findex IFCVT_MODIFY_CANCEL
+@item IFCVT_MODIFY_CANCEL
+A C expression to cancel any machine dependent modifications in
+converting code to conditional execution in the basic blocks
+@code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
 @end table