[PATCH] rs6000: Adjust loop_unroll_adjust to match middle-end change [PR 107692]

[Hongyu Wang <hongyu.wang@intel.com>]

Hi,

r13-3950-g071e428c24ee8c enables O2 small loop unrolling, but it breaks
-fno-unroll-loops for rs6000 with loop_unroll_adjust hook. Adjust the
option handling and target hook accordingly.

Bootstrapped & regtested on powerpc64le-linux-gnu, OK for trunk?

gcc/ChangeLog:

	PR target/107692
	* common/config/rs6000/rs6000-common.cc: Do not enable
	funroll-loops by default.
	* config/rs6000/rs6000.cc (rs6000_override_options_after_change):
	Remove flag override about loop unroll.
	(rs6000_loop_unroll_adjust): Turns off munroll-only-small-loops
	when explicit -f[no-]unroll-[all-]loops is set.
---
 gcc/common/config/rs6000/rs6000-common.cc |  6 +--
 gcc/config/rs6000/rs6000.cc               | 45 ++++++++++-------------
 2 files changed, 22 insertions(+), 29 deletions(-)

diff --git a/gcc/common/config/rs6000/rs6000-common.cc b/gcc/common/config/rs6000/rs6000-common.cc
index 8e393d08a23..7186d0c309c 100644
--- a/gcc/common/config/rs6000/rs6000-common.cc
+++ b/gcc/common/config/rs6000/rs6000-common.cc
@@ -34,9 +34,9 @@ static const struct default_options rs6000_option_optimization_table[] =
     { OPT_LEVELS_ALL, OPT_fsplit_wide_types_early, NULL, 1 },
     /* Enable -fsched-pressure for first pass instruction scheduling.  */
     { OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
-    /* Enable -munroll-only-small-loops with -funroll-loops to unroll small
-       loops at -O2 and above by default.  */
-    { OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_funroll_loops, NULL, 1 },
+
+    /* Enable -munroll-only-small-loops to unroll small loops at -O2 and
+       above by default.  */
     { OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_munroll_only_small_loops, NULL, 1 },
 
     /* -frename-registers leads to non-optimal codegen and performance
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index a85d7630b41..26e41b4b3b0 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -3392,22 +3392,6 @@ rs6000_md_asm_adjust (vec<rtx> & /*outputs*/, vec<rtx> & /*inputs*/,
 static void
 rs6000_override_options_after_change (void)
 {
-  /* Explicit -funroll-loops turns -munroll-only-small-loops off, and
-     turns -frename-registers on.  */
-  if ((OPTION_SET_P (flag_unroll_loops) && flag_unroll_loops)
-       || (OPTION_SET_P (flag_unroll_all_loops)
-	   && flag_unroll_all_loops))
-    {
-      if (!OPTION_SET_P (unroll_only_small_loops))
-	unroll_only_small_loops = 0;
-      if (!OPTION_SET_P (flag_rename_registers))
-	flag_rename_registers = 1;
-      if (!OPTION_SET_P (flag_cunroll_grow_size))
-	flag_cunroll_grow_size = 1;
-    }
-  else if (!OPTION_SET_P (flag_cunroll_grow_size))
-    flag_cunroll_grow_size = flag_peel_loops || optimize >= 3;
-
   /* If we are inserting ROP-protect instructions, disable shrink wrap.  */
   if (rs6000_rop_protect)
     flag_shrink_wrap = 0;
@@ -5540,17 +5524,26 @@ rs6000_cost_data::finish_cost (const vector_costs *scalar_costs)
 static unsigned
 rs6000_loop_unroll_adjust (unsigned nunroll, struct loop *loop)
 {
-   if (unroll_only_small_loops)
-    {
-      /* TODO: These are hardcoded values right now.  We probably should use
-	 a PARAM here.  */
-      if (loop->ninsns <= 6)
-	return MIN (4, nunroll);
-      if (loop->ninsns <= 10)
-	return MIN (2, nunroll);
+  if (!(flag_unroll_loops || flag_unroll_all_loops
+	|| loop->unroll))
+  {
+    unsigned nunroll_orig = nunroll;
+    nunroll = 1;
+    /* Any explicit -f{no-}unroll-{all-}loops turns off
+       -munroll-only-small-loops.  */
+    if (unroll_only_small_loops
+	&& !OPTION_SET_P (flag_unroll_loops))
+      {
+	/* TODO: These are hardcoded values right now.  We probably should use
+	   a PARAM here.  */
+	if (loop->ninsns <= 6)
+	  return MIN (4, nunroll_orig);
+	if (loop->ninsns <= 10)
+	  return MIN (2, nunroll_orig);
 
-      return 0;
-    }
+	return 0;
+      }
+  }
 
   return nunroll;
 }
-- 
2.18.1