tree-optimization/84201 - add --param vect-induction-float

This adds a --param to allow disabling of vectorization of
floating point inductions.  Ontop of -Ofast this should allow
549.fotonik3d_r to not miscompare.

2022-03-08  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84201
	* params.opt (-param=vect-induction-float): Add.
	* doc/invoke.texi (vect-induction-float): Document.
	* tree-vect-loop.cc (vectorizable_induction): Honor
	param_vect_induction_float.

	* gcc.dg/vect/pr84201.c: New testcase.

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b01ffab566af148e792e9aedc31aa0b19e730452..a0fa5e1cf434202b6832d7f289f41b6251ce076d 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -14989,6 +14989,9 @@ in an inner loop relative to the loop being vectorized.  The factor applied
 is the maximum of the estimated number of iterations of the inner loop and
 this parameter.  The default value of this parameter is 50.
 
+@item vect-induction-float
+Enable loop vectorization of floating point inductions.
+
 @item avoid-fma-max-bits
 Maximum number of bits for which we avoid creating FMAs.
 

diff --git a/gcc/params.opt b/gcc/params.opt
index f76f783991660abf9d30a79fa235c4df926fcd68..9561aa61a50260d08997c43c4fa2f1c8d867772d 100644 (file)
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -1176,6 +1176,10 @@ Controls how loop vectorizer uses partial vectors.  0 means never, 1 means only
 Common Joined UInteger Var(param_vect_inner_loop_cost_factor) Init(50) IntegerRange(1, 10000) Param Optimization
 The maximum factor which the loop vectorizer applies to the cost of statements in an inner loop relative to the loop being vectorized.
 
+-param=vect-induction-float=
+Common Joined UInteger Var(param_vect_induction_float) Init(1) IntegerRage(0, 1) Param Optimization
+Enable loop vectorization of floating point inductions.
+
 -param=vrp1-mode=
 Common Joined Var(param_vrp1_mode) Enum(vrp_mode) Init(VRP_MODE_VRP) Param Optimization
 --param=vrp1-mode=[vrp|ranger] Specifies the mode VRP1 should operate in.

diff --git a/gcc/testsuite/gcc.dg/vect/pr84201.c b/gcc/testsuite/gcc.dg/vect/pr84201.c
new file mode 100644 (file)
index 0000000..1cc6d1f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr84201.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-Ofast --param vect-induction-float=0" } */
+
+void foo (float *a, float f, float s, int n)
+{
+  for (int i = 0; i < n; ++i)
+    {
+      a[i] = f;
+      f += s;
+    }
+}
+
+void bar (double *a, double f, double s, int n)
+{
+  for (int i = 0; i < n; ++i)
+    {
+      a[i] = f;
+      f += s;
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "vectorized 0 loops" 2 "vect" } } */

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 1f30fc82ca14822c821806bd66d9f83f0c178e8c..7fcec12a3e9efa35fcd4e3584d054b439e57442a 100644 (file)
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -8175,6 +8175,14 @@ vectorizable_induction (loop_vec_info loop_vinfo,
       return false;
     }
 
+  if (FLOAT_TYPE_P (vectype) && !param_vect_induction_float)
+    {
+      if (dump_enabled_p ())
+       dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+                        "floating point induction vectorization disabled\n");
+      return false;
+    }
+
   step_expr = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_info);
   gcc_assert (step_expr != NULL_TREE);
   tree step_vectype = get_same_sized_vectype (TREE_TYPE (step_expr), vectype);