backport: re PR tree-optimization/77916 (ICE in verify_gimple_in_cfg: invalid (pointe...

[gcc]

2016-10-23  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	Backport from mainline
	2016-10-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/77916
	* gimple-ssa-strength-reduction.c (create_add_on_incoming_edge):
	Don't allow a MINUS_EXPR for pointer arithmetic for either known
	or unknown strides.
	(record_increment): Increments of -1 for unknown strides just use
	a multiply initializer like other negative values.
	(analyze_increments): Remove stopgap solution for -1 increment
	applied to pointer arithmetic.
	(insert_initializers): Requirement of initializer for -1 should be
	based on pointer-typedness of the candidate basis.

[gcc/testsuite]

2016-10-23  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	Backport from mainline
	2016-10-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/77916
	* gcc.dg/torture/pr77916.c: New.

From-SVN: r241462

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 880196d4bd193570b35d7fac968263b018afa5de..3260d52317fe52ac93c08b460ecc2362eb3f5486 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,19 @@
+2016-10-23  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+       Backport from mainline
+       2016-10-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+       PR tree-optimization/77916
+       * gimple-ssa-strength-reduction.c (create_add_on_incoming_edge):
+       Don't allow a MINUS_EXPR for pointer arithmetic for either known
+       or unknown strides.
+       (record_increment): Increments of -1 for unknown strides just use
+       a multiply initializer like other negative values.
+       (analyze_increments): Remove stopgap solution for -1 increment
+       applied to pointer arithmetic.
+       (insert_initializers): Requirement of initializer for -1 should be
+       based on pointer-typedness of the candidate basis.
+
 2016-10-19  Uros Bizjak  <ubizjak@gmail.com>
 
        PR target/77991

diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index cc56a6e86e7dcbe3412ca75a96ad224d4c6dc1b1..b9598a127d6daddfae12a487c8f909fa5b2f83fe 100644 (file)
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -2191,35 +2191,41 @@ create_add_on_incoming_edge (slsr_cand_t c, tree basis_name,
   basis_type = TREE_TYPE (basis_name);
   lhs = make_temp_ssa_name (basis_type, NULL, "slsr");
 
+  /* Occasionally people convert integers to pointers without a 
+     cast, leading us into trouble if we aren't careful.  */
+  enum tree_code plus_code
+    = POINTER_TYPE_P (basis_type) ? POINTER_PLUS_EXPR : PLUS_EXPR;
+
   if (known_stride)
     {
       tree bump_tree;
-      enum tree_code code = PLUS_EXPR;
+      enum tree_code code = plus_code;
       widest_int bump = increment * wi::to_widest (c->stride);
-      if (wi::neg_p (bump))
+      if (wi::neg_p (bump) && !POINTER_TYPE_P (basis_type))
        {
          code = MINUS_EXPR;
          bump = -bump;
        }
 
-      bump_tree = wide_int_to_tree (basis_type, bump);
+      tree stride_type = POINTER_TYPE_P (basis_type) ? sizetype : basis_type;
+      bump_tree = wide_int_to_tree (stride_type, bump);
       new_stmt = gimple_build_assign (lhs, code, basis_name, bump_tree);
     }
   else
     {
       int i;
-      bool negate_incr = (!address_arithmetic_p && wi::neg_p (increment));
+      bool negate_incr = !POINTER_TYPE_P (basis_type) && wi::neg_p (increment);
       i = incr_vec_index (negate_incr ? -increment : increment);
       gcc_assert (i >= 0);
 
       if (incr_vec[i].initializer)
        {
-         enum tree_code code = negate_incr ? MINUS_EXPR : PLUS_EXPR;
+         enum tree_code code = negate_incr ? MINUS_EXPR : plus_code;
          new_stmt = gimple_build_assign (lhs, code, basis_name,
                                          incr_vec[i].initializer);
        }
       else if (increment == 1)
-       new_stmt = gimple_build_assign (lhs, PLUS_EXPR, basis_name, c->stride);
+       new_stmt = gimple_build_assign (lhs, plus_code, basis_name, c->stride);
       else if (increment == -1)
        new_stmt = gimple_build_assign (lhs, MINUS_EXPR, basis_name,
                                        c->stride);
@@ -2538,13 +2544,13 @@ record_increment (slsr_cand_t c, widest_int increment, bool is_phi_adjust)
       /* Optimistically record the first occurrence of this increment
         as providing an initializer (if it does); we will revise this
         opinion later if it doesn't dominate all other occurrences.
-         Exception:  increments of -1, 0, 1 never need initializers;
+        Exception:  increments of 0, 1 never need initializers;
         and phi adjustments don't ever provide initializers.  */
       if (c->kind == CAND_ADD
          && !is_phi_adjust
          && c->index == increment
          && (wi::gts_p (increment, 1)
-             || wi::lts_p (increment, -1))
+             || wi::lts_p (increment, 0))
          && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR
              || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR))
        {
@@ -2857,11 +2863,6 @@ analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed)
                   && !POINTER_TYPE_P (first_dep->cand_type)))
        incr_vec[i].cost = COST_NEUTRAL;
 
-      /* FIXME: We don't handle pointers with a -1 increment yet.
-         They are usually unprofitable anyway.  */
-      else if (incr == -1 && POINTER_TYPE_P (first_dep->cand_type))
-       incr_vec[i].cost = COST_INFINITE;
-      
       /* FORNOW: If we need to add an initializer, give up if a cast from
         the candidate's type to its stride's type can lose precision.
         This could eventually be handled better by expressly retaining the
@@ -3148,7 +3149,7 @@ insert_initializers (slsr_cand_t c)
       if (!profitable_increment_p (i)
          || incr == 1
          || (incr == -1
-             && gimple_assign_rhs_code (c->cand_stmt) != POINTER_PLUS_EXPR)
+             && (!POINTER_TYPE_P (lookup_cand (c->basis)->cand_type)))
          || incr == 0)
        continue;
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 020ee03d14d2d5679d48ae98e32935f9ae00c01f..b97119d3adfd0f0ec1b359d562dfbe9420e39ef7 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2016-10-23  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+       Backport from mainline
+       2016-10-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+       PR tree-optimization/77916
+       * gcc.dg/torture/pr77916.c: New.
+
 2016-10-19  Uros Bizjak  <ubizjak@gmail.com>
 
        PR target/77991

diff --git a/gcc/testsuite/gcc.dg/torture/pr77916.c b/gcc/testsuite/gcc.dg/torture/pr77916.c
new file mode 100644 (file)
index 0000000..f29f099
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr77916.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -Wno-int-conversion" } */
+
+/* PR77916: This failed with "error: invalid (pointer) operands to plus/minus"
+   after SLSR.  */
+
+typedef struct
+{
+  void *f1;
+} S;
+
+S *a;
+int b;
+
+void
+fn1 (void)
+{
+  for (; b; b++, a++)
+    a->f1 = b;
+}