re PR rtl-optimization/21254 (Incorrect code with -funroll-loops for multiple targets...

	PR rtl-optimization/21254
	* loop-iv.c (iv_number_of_iterations): Simplify infiniteness
	assumptions for loops that otherwise do not roll.
	(find_simple_exit): Prefer # of iterations that is guaranteed
	not to be infinite.
	* loop-unroll.c (decide_peel_once_rolling,
	decide_peel_completely): Check whether the loop is infinite.

From-SVN: r99332

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e98ebef3defb97ffe1b00dc541cf20ed526ab3e4..e579c1de34262f828ede0648d7a70d421b0149c5 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2005-05-06  Zdenek Dvorak  <dvorakz@suse.cz>
+
+       PR rtl-optimization/21254
+       * loop-iv.c (iv_number_of_iterations): Simplify infiniteness
+       assumptions for loops that otherwise do not roll.
+       (find_simple_exit): Prefer # of iterations that is guaranteed
+       not to be infinite.
+       * loop-unroll.c (decide_peel_once_rolling,
+       decide_peel_completely): Check whether the loop is infinite.
+
 2005-05-06  Pat Haugen  <pthaugen@us.ibm.com>
 
        * config/rs6000/sysv4.opt: Fix typo.

diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c
index 09ed73c6324287ac566e1fe403d066fb37f4ef0f..bacf8382b7f9440937419d84c74b7847b109c5d0 100644 (file)
--- a/gcc/loop-iv.c
+++ b/gcc/loop-iv.c
@@ -2148,7 +2148,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
            assumption = simplify_gen_relational (EQ, SImode, mode, tmp,
                                                  mode_mmax);
            if (assumption == const_true_rtx)
-             goto zero_iter;
+             goto zero_iter_simplify;
            iv0.base = simplify_gen_binary (PLUS, comp_mode,
                                            iv0.base, const1_rtx);
          }
@@ -2158,7 +2158,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
            assumption = simplify_gen_relational (EQ, SImode, mode, tmp,
                                                  mode_mmin);
            if (assumption == const_true_rtx)
-             goto zero_iter;
+             goto zero_iter_simplify;
            iv1.base = simplify_gen_binary (PLUS, comp_mode,
                                            iv1.base, constm1_rtx);
          }
@@ -2185,7 +2185,8 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
            {
              desc->infinite =
                      alloc_EXPR_LIST (0, const_true_rtx, NULL_RTX);
-             return;
+             /* Fill in the remaining fields somehow.  */
+             goto zero_iter_simplify;
            }
        }
       else
@@ -2195,7 +2196,8 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
            {
              desc->infinite =
                      alloc_EXPR_LIST (0, const_true_rtx, NULL_RTX);
-             return;
+             /* Fill in the remaining fields somehow.  */
+             goto zero_iter_simplify;
            }
        }
     }
@@ -2306,7 +2308,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
          assumption = simplify_gen_relational (reverse_condition (cond),
                                                SImode, mode, tmp0, tmp1);
          if (assumption == const_true_rtx)
-           goto zero_iter;
+           goto zero_iter_simplify;
          else if (assumption != const0_rtx)
            desc->noloop_assumptions =
                    alloc_EXPR_LIST (0, assumption, desc->noloop_assumptions);
@@ -2449,7 +2451,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
          delta = simplify_gen_binary (MINUS, mode, tmp1, delta);
        }
       if (assumption == const_true_rtx)
-       goto zero_iter;
+       goto zero_iter_simplify;
       else if (assumption != const0_rtx)
        desc->noloop_assumptions =
                alloc_EXPR_LIST (0, assumption, desc->noloop_assumptions);
@@ -2517,16 +2519,26 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
 
   return;
 
-fail:
-  desc->simple_p = false;
-  return;
+zero_iter_simplify:
+  /* Simplify the assumptions.  */
+  simplify_using_initial_values (loop, AND, &desc->assumptions);
+  if (desc->assumptions
+      && XEXP (desc->assumptions, 0) == const0_rtx)
+    goto fail;
+  simplify_using_initial_values (loop, IOR, &desc->infinite);
 
+  /* Fallthru.  */
 zero_iter:
   desc->const_iter = true;
   desc->niter = 0;
   desc->niter_max = 0;
+  desc->noloop_assumptions = NULL_RTX;
   desc->niter_expr = const0_rtx;
   return;
+
+fail:
+  desc->simple_p = false;
+  return;
 }
 
 /* Checks whether E is a simple exit from LOOP and stores its description
@@ -2603,12 +2615,21 @@ find_simple_exit (struct loop *loop, struct niter_desc *desc)
          if (!act.simple_p)
            continue;
 
-         /* Prefer constant iterations; the less the better.  */
          if (!any)
            any = true;
-         else if (!act.const_iter
-                  || (desc->const_iter && act.niter >= desc->niter))
-           continue;
+         else
+           {
+             /* Prefer constant iterations; the less the better.  */
+             if (!act.const_iter
+                 || (desc->const_iter && act.niter >= desc->niter))
+               continue;
+
+             /* Also if the actual exit may be infinite, while the old one
+                not, prefer the old one.  */
+             if (act.infinite && !desc->infinite)
+               continue;
+           }
+         
          *desc = act;
        }
     }

diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c
index 409df0caa6e712f25efd7427f5b4fc3888840a90..68512d02a5a796139c3ebb6c51cbe4400522874d 100644 (file)
--- a/gcc/loop-unroll.c
+++ b/gcc/loop-unroll.c
@@ -375,6 +375,7 @@ decide_peel_once_rolling (struct loop *loop, int flags ATTRIBUTE_UNUSED)
   /* Check number of iterations.  */
   if (!desc->simple_p
       || desc->assumptions
+      || desc->infinite
       || !desc->const_iter
       || desc->niter != 0)
     {
@@ -444,7 +445,8 @@ decide_peel_completely (struct loop *loop, int flags ATTRIBUTE_UNUSED)
   /* Check number of iterations.  */
   if (!desc->simple_p
       || desc->assumptions
-      || !desc->const_iter)
+      || !desc->const_iter
+      || desc->infinite)
     {
       if (dump_file)
        fprintf (dump_file,