tree-optimization/122680 - avoid range query during vect transform

Range queries during analysis on the original loop might not yield
the same result as those on the epilog during transform.  Separate
analysis from transform here.

	PR tree-optimization/122680
	* tree-vect-stmts.cc (vectorizable_conversion): Avoid range
	queries during transform.

	* gcc.dg/vect/pr122680.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/vect/pr122680.c b/gcc/testsuite/gcc.dg/vect/pr122680.c
new file mode 100644 (file)
index 0000000..3e25a3f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr122680.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3" } */
+/* { dg-additional-options "-mavx2" { target avx2 } } */
+
+void
+foo (float *buf)
+{
+  for (unsigned long i = 0, j = 100; i < 100; i++, j--)
+    buf[i] = j;
+}

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index b0f15902c8195c2b7650a5a2b41de389fce7f342..d08f5f19fd4449def710b0fe94108b87118352c2 100644 (file)
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -5580,23 +5580,26 @@ vectorizable_conversion (vec_info *vinfo,
         truncate it to cvt_type and the do FLOAT_EXPR.  */
       else if (code == FLOAT_EXPR)
        {
-         wide_int op_min_value, op_max_value;
-         tree def;
-         /* ???  Merge ranges in case of more than one lane.  */
-         if (SLP_TREE_LANES (slp_op0) != 1
-             || !(def = vect_get_slp_scalar_def (slp_op0, 0))
-             || !vect_get_range_info (def, &op_min_value, &op_max_value))
-           goto unsupported;
+         if (cost_vec)
+           {
+             wide_int op_min_value, op_max_value;
+             tree def;
+
+             /* ???  Merge ranges in case of more than one lane.  */
+             if (SLP_TREE_LANES (slp_op0) != 1
+                 || !(def = vect_get_slp_scalar_def (slp_op0, 0))
+                 || !vect_get_range_info (def, &op_min_value, &op_max_value))
+               goto unsupported;
+
+             if ((wi::min_precision (op_max_value, SIGNED)
+                  > GET_MODE_BITSIZE (lhs_mode))
+                 || (wi::min_precision (op_min_value, SIGNED)
+                     > GET_MODE_BITSIZE (lhs_mode)))
+               goto unsupported;
+           }
 
          cvt_type
            = build_nonstandard_integer_type (GET_MODE_BITSIZE (lhs_mode), 0);
-         if (cvt_type == NULL_TREE
-             || (wi::min_precision (op_max_value, SIGNED)
-                 > TYPE_PRECISION (cvt_type))
-             || (wi::min_precision (op_min_value, SIGNED)
-                 > TYPE_PRECISION (cvt_type)))
-           goto unsupported;
-
          cvt_type = get_same_sized_vectype (cvt_type, vectype_out);
          if (cvt_type == NULL_TREE)
            goto unsupported;