vectorizer: Fix up -fsimd-cost-model= handling

>	* testsuite/libgomp.c++/scan-10.C: Add option -fvect-cost-model=cheap.

I don't think this is the right thing to do.
This just means that at some point between 2013 when -fsimd-cost-model has
been introduced and now -fsimd-cost-model= option at least partially stopped
working properly.
As documented, -fsimd-cost-model= overrides the -fvect-cost-model= setting
for OpenMP simd loops (loop->force_vectorize is true) if specified differently
from default.
In tree-vectorizer.h we have:
static inline bool
unlimited_cost_model (loop_p loop)
{
  if (loop != NULL && loop->force_vectorize
      && flag_simd_cost_model != VECT_COST_MODEL_DEFAULT)
    return flag_simd_cost_model == VECT_COST_MODEL_UNLIMITED;
  return (flag_vect_cost_model == VECT_COST_MODEL_UNLIMITED);
}
and use it in various places, but we also just use flag_vect_cost_model
in lots of places (and in one spot use flag_simd_cost_model, not sure if
we are sure it is a force_vectorize loop or what).

So, IMHO we should change the above inline function to
loop_cost_model and let it return the cost model and then just
reimplement unlimited_cost_model as
return loop_cost_model (loop) == VECT_COST_MODEL_UNLIMITED;
and then adjust the direct uses of the flag and revert these changes.

2021-10-12  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* tree-vectorizer.h (loop_cost_model): New function.
	(unlimited_cost_model): Use it.
	* tree-vect-loop.c (vect_analyze_loop_costing): Use loop_cost_model
	call instead of flag_vect_cost_model.
	* tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Likewise.
	(vect_prune_runtime_alias_test_list): Likewise.  Also use it instead
	of flag_simd_cost_model.
gcc/testsuite/
	* gcc.dg/gomp/simd-2.c: Remove option -fvect-cost-model=cheap.
	* gcc.dg/gomp/simd-3.c: Likewise.
libgomp/
	* testsuite/libgomp.c/scan-11.c: Remove option -fvect-cost-model=cheap.
	* testsuite/libgomp.c/scan-12.c: Likewise.
	* testsuite/libgomp.c/scan-13.c: Likewise.
	* testsuite/libgomp.c/scan-14.c: Likewise.
	* testsuite/libgomp.c/scan-15.c: Likewise.
	* testsuite/libgomp.c/scan-16.c: Likewise.
	* testsuite/libgomp.c/scan-17.c: Likewise.
	* testsuite/libgomp.c/scan-18.c: Likewise.
	* testsuite/libgomp.c/scan-19.c: Likewise.
	* testsuite/libgomp.c/scan-20.c: Likewise.
	* testsuite/libgomp.c/scan-21.c: Likewise.
	* testsuite/libgomp.c/scan-22.c: Likewise.
	* testsuite/libgomp.c++/scan-9.C: Likewise.
	* testsuite/libgomp.c++/scan-10.C: Likewise.
	* testsuite/libgomp.c++/scan-11.C: Likewise.
	* testsuite/libgomp.c++/scan-12.C: Likewise.
	* testsuite/libgomp.c++/scan-13.C: Likewise.
	* testsuite/libgomp.c++/scan-14.C: Likewise.
	* testsuite/libgomp.c++/scan-15.C: Likewise.
	* testsuite/libgomp.c++/scan-16.C: Likewise.

5 files changed, 22 insertions, 12 deletions

diff --git a/gcc/testsuite/gcc.dg/gomp/simd-2.c b/gcc/testsuite/gcc.dg/gomp/simd-2.c
index f491212..85acb98 100644
--- a/gcc/testsuite/gcc.dg/gomp/simd-2.c
+++ b/gcc/testsuite/gcc.dg/gomp/simd-2.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fopenmp -fvect-cost-model=cheap -fdump-tree-vect-details" } */
+/* { dg-options "-O2 -fopenmp -fdump-tree-vect-details" } */
 /* { dg-additional-options "-msse2" { target { i?86-*-* x86_64-*-* } } } */
 /* { dg-additional-options "-mavx" { target avx } } */
 /* { dg-final { scan-tree-dump-times "vectorized \[1-9]\[0-9]* loops in function" 5 "vect" { target i?86-*-* x86_64-*-* aarch64-*-* } } } */
diff --git a/gcc/testsuite/gcc.dg/gomp/simd-3.c b/gcc/testsuite/gcc.dg/gomp/simd-3.c
index c75060c..86fee85 100644
--- a/gcc/testsuite/gcc.dg/gomp/simd-3.c
+++ b/gcc/testsuite/gcc.dg/gomp/simd-3.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fopenmp -fvect-cost-model=cheap -fdump-tree-vect-details" } */
+/* { dg-options "-O2 -fopenmp -fdump-tree-vect-details" } */
 /* { dg-additional-options "-msse2" { target { i?86-*-* x86_64-*-* } } } */
 /* { dg-additional-options "-mavx" { target avx } } */
 /* { dg-final { scan-tree-dump-times "vectorized \[1-9]\[0-9]* loops in function" 5 "vect" { target i?86-*-* x86_64-*-* aarch64-*-* } } } */
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c
index 07b5ba1..1e13148 100644
--- a/gcc/tree-vect-data-refs.c
+++ b/gcc/tree-vect-data-refs.c
@@ -2236,7 +2236,7 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
         {
           unsigned max_allowed_peel
 	    = param_vect_max_peeling_for_alignment;
-	  if (flag_vect_cost_model <= VECT_COST_MODEL_CHEAP)
+	  if (loop_cost_model (loop) <= VECT_COST_MODEL_CHEAP)
 	    max_allowed_peel = 0;
           if (max_allowed_peel != (unsigned)-1)
             {
@@ -2334,7 +2334,7 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
   do_versioning
     = (optimize_loop_nest_for_speed_p (loop)
        && !loop->inner /* FORNOW */
-       && flag_vect_cost_model > VECT_COST_MODEL_CHEAP);
+       && loop_cost_model (loop) > VECT_COST_MODEL_CHEAP);
 
   if (do_versioning)
     {
@@ -3751,7 +3751,9 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
   unsigned int count = (comp_alias_ddrs.length ()
 			+ check_unequal_addrs.length ());
 
-  if (count && flag_vect_cost_model == VECT_COST_MODEL_VERY_CHEAP)
+  if (count
+      && (loop_cost_model (LOOP_VINFO_LOOP (loop_vinfo))
+	  == VECT_COST_MODEL_VERY_CHEAP))
     return opt_result::failure_at
       (vect_location, "would need a runtime alias check\n");
 
@@ -3760,7 +3762,7 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
 		     "improved number of alias checks from %d to %d\n",
 		     may_alias_ddrs.length (), count);
   unsigned limit = param_vect_max_version_for_alias_checks;
-  if (flag_simd_cost_model == VECT_COST_MODEL_CHEAP)
+  if (loop_cost_model (LOOP_VINFO_LOOP (loop_vinfo)) == VECT_COST_MODEL_CHEAP)
     limit = param_vect_max_version_for_alias_checks * 6 / 10;
   if (count > limit)
     return opt_result::failure_at
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index e94356d..961c162 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -1850,7 +1850,7 @@ vect_analyze_loop_costing (loop_vec_info loop_vinfo)
 
   /* If using the "very cheap" model. reject cases in which we'd keep
      a copy of the scalar code (even if we might be able to vectorize it).  */
-  if (flag_vect_cost_model == VECT_COST_MODEL_VERY_CHEAP
+  if (loop_cost_model (loop) == VECT_COST_MODEL_VERY_CHEAP
       && (LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo)
 	  || LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)
 	  || LOOP_VINFO_PEELING_FOR_NITER (loop_vinfo)))
@@ -1922,7 +1922,7 @@ vect_analyze_loop_costing (loop_vec_info loop_vinfo)
   /* If the vector loop needs multiple iterations to be beneficial then
      things are probably too close to call, and the conservative thing
      would be to stick with the scalar code.  */
-  if (flag_vect_cost_model == VECT_COST_MODEL_VERY_CHEAP
+  if (loop_cost_model (loop) == VECT_COST_MODEL_VERY_CHEAP
       && min_profitable_estimate > (int) vect_vf_for_cost (loop_vinfo))
     {
       if (dump_enabled_p ())
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index ed4a7ff..4aa84ac 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -1701,14 +1701,22 @@ get_dr_vinfo_offset (vec_info *vinfo,
 }
 
 
+/* Return the vect cost model for LOOP.  */
+static inline enum vect_cost_model
+loop_cost_model (loop_p loop)
+{
+  if (loop != NULL
+      && loop->force_vectorize
+      && flag_simd_cost_model != VECT_COST_MODEL_DEFAULT)
+    return flag_simd_cost_model;
+  return flag_vect_cost_model;
+}
+
 /* Return true if the vect cost model is unlimited.  */
 static inline bool
 unlimited_cost_model (loop_p loop)
 {
-  if (loop != NULL && loop->force_vectorize
-      && flag_simd_cost_model != VECT_COST_MODEL_DEFAULT)
-    return flag_simd_cost_model == VECT_COST_MODEL_UNLIMITED;
-  return (flag_vect_cost_model == VECT_COST_MODEL_UNLIMITED);
+  return loop_cost_model (loop) == VECT_COST_MODEL_UNLIMITED;
 }
 
 /* Return true if the loop described by LOOP_VINFO is fully-masked and