re PR rtl-optimization/69052 (Performance regression after r229402.)

	PR tree-optimization/69052
	* loop-invariant.c (canonicalize_address): New function.
	(inv_can_prop_to_addr_use): Check validity of address expression
	which is canonicalized by above function.

	gcc/testsuite/ChangeLog
	PR tree-optimization/69052
	* gcc.target/i386/pr69052.c: New test.

From-SVN: r233907

gcc/ChangeLog

+2016-03-02  Bin Cheng  <bin.cheng@arm.com>
+
+	PR tree-optimization/69052
+	* loop-invariant.c (canonicalize_address): New function.
+	(inv_can_prop_to_addr_use): Check validity of address expression
+	which is canonicalized by above function.
+
 2016-03-02  Alan Modra  <amodra@gmail.com>
 
 	PR ipa/69990

gcc/loop-invariant.c

@@ -52,6 +52,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "cfgloop.h"
 #include "expr.h"
 #include "params.h"
+#include "rtl-iter.h"
 #include "dumpfile.h"
 
 /* The data stored for the loop.  */
@@ -754,6 +755,130 @@ create_new_invariant (struct def *def, rtx_insn *insn, bitmap depends_on,
   return inv;
 }
 
+/* Return a canonical version of X for the address, from the point of view,
+   that all multiplications are represented as MULT instead of the multiply
+   by a power of 2 being represented as ASHIFT.
+
+   Callers should prepare a copy of X because this function may modify it
+   in place.  */
+
+static void
+canonicalize_address_mult (rtx x)
+{
+  subrtx_var_iterator::array_type array;
+  FOR_EACH_SUBRTX_VAR (iter, array, x, NONCONST)
+    {
+      rtx sub = *iter;
+
+      if (GET_CODE (sub) == ASHIFT
+	  && CONST_INT_P (XEXP (sub, 1))
+	  && INTVAL (XEXP (sub, 1)) < GET_MODE_BITSIZE (GET_MODE (sub))
+	  && INTVAL (XEXP (sub, 1)) >= 0)
+	{
+	  HOST_WIDE_INT shift = INTVAL (XEXP (sub, 1));
+	  PUT_CODE (sub, MULT);
+	  XEXP (sub, 1) = gen_int_mode ((HOST_WIDE_INT) 1 << shift,
+					GET_MODE (sub));
+	  iter.skip_subrtxes ();
+	}
+    }
+}
+
+/* Maximum number of sub expressions in address.  We set it to
+   a small integer since it's unlikely to have a complicated
+   address expression.  */
+
+#define MAX_CANON_ADDR_PARTS (5)
+
+/* Collect sub expressions in address X with PLUS as the seperator.
+   Sub expressions are stored in vector ADDR_PARTS.  */
+
+static void
+collect_address_parts (rtx x, vec<rtx> *addr_parts)
+{
+  subrtx_var_iterator::array_type array;
+  FOR_EACH_SUBRTX_VAR (iter, array, x, NONCONST)
+    {
+      rtx sub = *iter;
+
+      if (GET_CODE (sub) != PLUS)
+	{
+	  addr_parts->safe_push (sub);
+	  iter.skip_subrtxes ();
+	}
+    }
+}
+
+/* Compare function for sorting sub expressions X and Y based on
+   precedence defined for communitive operations.  */
+
+static int
+compare_address_parts (const void *x, const void *y)
+{
+  const rtx *rx = (const rtx *)x;
+  const rtx *ry = (const rtx *)y;
+  int px = commutative_operand_precedence (*rx);
+  int py = commutative_operand_precedence (*ry);
+
+  return (py - px);
+}
+
+/* Return a canonical version address for X by following steps:
+     1) Rewrite ASHIFT into MULT recursively.
+     2) Divide address into sub expressions with PLUS as the
+	separator.
+     3) Sort sub expressions according to precedence defined
+	for communative operations.
+     4) Simplify CONST_INT_P sub expressions.
+     5) Create new canonicalized address and return.
+   Callers should prepare a copy of X because this function may
+   modify it in place.  */
+
+static rtx
+canonicalize_address (rtx x)
+{
+  rtx res;
+  unsigned int i, j;
+  machine_mode mode = GET_MODE (x);
+  auto_vec<rtx, MAX_CANON_ADDR_PARTS> addr_parts;
+
+  /* Rewrite ASHIFT into MULT.  */
+  canonicalize_address_mult (x);
+  /* Divide address into sub expressions.  */
+  collect_address_parts (x, &addr_parts);
+  /* Unlikely to have very complicated address.  */
+  if (addr_parts.length () < 2
+      || addr_parts.length () > MAX_CANON_ADDR_PARTS)
+    return x;
+
+  /* Sort sub expressions according to canonicalization precedence.  */
+  addr_parts.qsort (compare_address_parts);
+
+  /* Simplify all constant int summary if possible.  */
+  for (i = 0; i < addr_parts.length (); i++)
+    if (CONST_INT_P (addr_parts[i]))
+      break;
+
+  for (j = i + 1; j < addr_parts.length (); j++)
+    {
+      gcc_assert (CONST_INT_P (addr_parts[j]));
+      addr_parts[i] = simplify_gen_binary (PLUS, mode,
+					   addr_parts[i],
+					   addr_parts[j]);
+    }
+
+  /* Chain PLUS operators to the left for !CONST_INT_P sub expressions.  */
+  res = addr_parts[0];
+  for (j = 1; j < i; j++)
+    res = simplify_gen_binary (PLUS, mode, res, addr_parts[j]);
+
+  /* Pickup the last CONST_INT_P sub expression.  */
+  if (i < addr_parts.length ())
+    res = simplify_gen_binary (PLUS, mode, res, addr_parts[i]);
+
+  return res;
+}
+
 /* Given invariant DEF and its address USE, check if the corresponding
    invariant expr can be propagated into the use or not.  */
 
@@ -761,7 +886,7 @@ static bool
 inv_can_prop_to_addr_use (struct def *def, df_ref use)
 {
   struct invariant *inv;
-  rtx *pos = DF_REF_REAL_LOC (use), def_set;
+  rtx *pos = DF_REF_REAL_LOC (use), def_set, use_set;
   rtx_insn *use_insn = DF_REF_INSN (use);
   rtx_insn *def_insn;
   bool ok;
@@ -778,6 +903,29 @@ inv_can_prop_to_addr_use (struct def *def, df_ref use)
 
   validate_unshare_change (use_insn, pos, SET_SRC (def_set), true);
   ok = verify_changes (0);
+  /* Try harder with canonicalization in address expression.  */
+  if (!ok && (use_set = single_set (use_insn)) != NULL_RTX)
+    {
+      rtx src, dest, mem = NULL_RTX;
+
+      src = SET_SRC (use_set);
+      dest = SET_DEST (use_set);
+      if (MEM_P (src))
+	mem = src;
+      else if (MEM_P (dest))
+	mem = dest;
+
+      if (mem != NULL_RTX
+	  && !memory_address_addr_space_p (GET_MODE (mem),
+					   XEXP (mem, 0),
+					   MEM_ADDR_SPACE (mem)))
+	{
+	  rtx addr = canonicalize_address (copy_rtx (XEXP (mem, 0)));
+	  if (memory_address_addr_space_p (GET_MODE (mem),
+					   addr, MEM_ADDR_SPACE (mem)))
+	    ok = true;
+	}
+    }
   cancel_changes (0);
   return ok;
 }

gcc/testsuite/ChangeLog

+2016-03-02  Bin Cheng  <bin.cheng@arm.com>
+
+	PR tree-optimization/69052
+	* gcc.target/i386/pr69052.c: New test.
+
 2016-03-02  Alan Modra  <amodra@gmail.com>
 
 	* gcc.dg/pr69990.c: New.

gcc/testsuite/gcc.target/i386/pr69052.c

+/* { dg-do compile } */
+/* { dg-require-effective-target pie } */
+/* { dg-options "-O2 -fPIE -pie" } */
+
+int look_nbits[256], loop_sym[256];
+const int ind[] = {
+  0,  1,  8, 16,  9,  2,  3, 10, 17, 24, 32, 25, 18, 11,  4,  5,
+ 12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13,  6,  7, 14, 21, 28,
+ 35, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51,
+ 58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63
+};
+int out[256];
+extern void bar (int *, int *);
+void foo (int *l1, int *l2, int *v, int *v1, int *m1, int i)
+{
+  int L = i + 1, b = 20;
+  int result, k;
+
+  for (k = 1; k < 64; k++)
+    {
+      int look = (((L >> (b - 8))) & ((1 << 8) - 1));
+      int nb = l1[look];
+      int code;
+      int r;
+
+      if (nb)
+	{
+	  b -= nb;
+	  result = l2[look];
+	}
+      else
+	{
+	  nb = 9;
+	  code = (((L >> (b -= nb))) & ((1 << nb) - 1));
+	  result = v[(code + v1[nb])];
+	}
+      r = result >> 4;
+      result &= 15;
+      if (result)
+	{
+	  k += r;
+	  r = (((L >> (b -= result))) & ((1 << result) - 1));
+	  if (r < (1 << (result - 1)))
+	    result = r + (((-1) << result) + 1);
+	  else
+	    result = r;
+
+	  out[ind[k]] = result;
+	}
+      bar (&L, &b);
+    }
+}
+
+/* { dg-final { scan-assembler-not "leal\[ \t\]ind@GOTOFF\\(%\[^,\]*\\), %" { target ia32 } } } */