RE: [PATCH] Enhance final_value_replacement_loop to handle bitop with an invariant induction.[PR105735]

["Kong, Lingling" <lingling.kong@intel.com>]

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Hi Richard,

Thanks you so much for reviewing this patch.  I really appreciate it. For these review comments, I have made some changes.

> That's a single-stmt match, you shouldn't use match.pd matching for this.
> Instead just do
> 
>   if (is_gimple_assign (stmt)
>       && ((code = gimple_assign_rhs_code (stmt)), true)
>       && (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code ==
> BIT_XOR_EXPR))

Yes, I fixed it and dropped modification for match.pd.

> and pick gimple_assign_rhs{1,2} (stmt) as the operands.  The :c in bit_op:c is
> redundant btw. - while the name suggests "with invariant" you don't actually
> check for that.  But again, given canonicalization rules the invariant will be rhs2
> so above add
> 
>         && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST

For " with invariant", this needed op1 is invariant, and I used `expr_invariant_in_loop_p (loop, match_op[0])` for check.
And op2 just be PHI is ok. If op2 is INTEGER_CST, existing gcc can be directly optimized and do not need modification.

> you probably need dg-require-effective-target longlong, but is it necessary to
> use long long for the testcases in the first place?
> The IV seems to be unused, if it should match the variables bit size use sizeof
> (type) * 8

Yes, It is not necessary to use long long for the testcases. I changed type to unsigned int.

> > +  inv = PHI_ARG_DEF_FROM_EDGE (header_phi, loop_preheader_edge
> > + (loop));  return fold_build2 (code1, type, inv, match_op[0]); }
> 
> The } goes to the next line.

Sorry, It might be something wrong with my use of gcc send-email format.

> > +      tree bitinv_def;
> > +      if ((bitinv_def
> 
> please use else if here

Sorry, If use the else if here, there is no corresponding above if. I'm not sure if you mean change bitwise induction expression if to else if.

Do you agree with these changes?  Thanks again for taking a look.

Thanks,
Lingling

> -----Original Message-----
> From: Richard Biener <richard.guenther@gmail.com>
> Sent: Tuesday, August 23, 2022 3:27 PM
> To: Kong, Lingling <lingling.kong@intel.com>
> Cc: Liu, Hongtao <hongtao.liu@intel.com>; gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] Enhance final_value_replacement_loop to handle bitop
> with an invariant induction.[PR105735]
> 
> On Thu, Aug 18, 2022 at 8:48 AM Kong, Lingling via Gcc-patches <gcc-
> patches@gcc.gnu.org> wrote:
> >
> > Hi,
> >
> > This patch is for pr105735/pr101991. It will enable below optimization:
> > {
> > -  long unsigned int bit;
> > -
> > -  <bb 2> [local count: 32534376]:
> > -
> > -  <bb 3> [local count: 1041207449]:
> > -  # tmp_10 = PHI <tmp_7(5), tmp_4(D)(2)>
> > -  # bit_12 = PHI <bit_8(5), 0(2)>
> > -  tmp_7 = bit2_6(D) & tmp_10;
> > -  bit_8 = bit_12 + 1;
> > -  if (bit_8 != 32)
> > -    goto <bb 5>; [96.97%]
> > -  else
> > -    goto <bb 4>; [3.03%]
> > -
> > -  <bb 5> [local count: 1009658865]:
> > -  goto <bb 3>; [100.00%]
> > -
> > -  <bb 4> [local count: 32534376]:
> > -  # tmp_11 = PHI <tmp_7(3)>
> > -  return tmp_11;
> > +  tmp_11 = tmp_4(D) & bit2_6(D);
> > +  return tmp_11;
> >
> > }
> >
> > Ok for master ?
> >
> > gcc/ChangeLog:
> >
> >         PR middle-end/105735
> >         * match.pd (bitop_with_inv_p): New match.
> >         * tree-scalar-evolution.cc (gimple_bitop_with_inv_p): Declare.
> >         (analyze_and_compute_bitop_with_inv_effect): New function.
> >         (final_value_replacement_loop): Enhanced to handle bitop
> >         with inv induction.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * gcc.target/i386/pr105735-1.c: New test.
> >         * gcc.target/i386/pr105735-2.c: New test.
> > ---
> >  gcc/match.pd                               |  4 +
> >  gcc/testsuite/gcc.target/i386/pr105735-1.c | 88 ++++++++++++++++++++++
> gcc/testsuite/gcc.target/i386/pr105735-2.c | 28 +++++++
> >  gcc/tree-scalar-evolution.cc               | 59 +++++++++++++++
> >  4 files changed, 179 insertions(+)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/pr105735-1.c
> >  create mode 100644 gcc/testsuite/gcc.target/i386/pr105735-2.c
> >
> > diff --git a/gcc/match.pd b/gcc/match.pd index
> > 562138a8034..cfe593ebb02 100644
> > --- a/gcc/match.pd
> > +++ b/gcc/match.pd
> > @@ -8050,6 +8050,10 @@ and,
> >   (bit_not
> >    (nop_convert1? (bit_xor@0 (convert2? (lshift integer_onep@1 @2))
> > @3))))
> >
> > +(for bit_op (bit_and bit_ior bit_xor)  (match (bitop_with_inv_p @0
> > +@1)
> > +  (bit_op:c @0 @1)))
> > +
> 
> That's a single-stmt match, you shouldn't use match.pd matching for this.
> Instead just do
> 
>   if (is_gimple_assign (stmt)
>       && ((code = gimple_assign_rhs_code (stmt)), true)
>       && (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code ==
> BIT_XOR_EXPR))
>    ..
> 
> and pick gimple_assign_rhs{1,2} (stmt) as the operands.  The :c in bit_op:c is
> redundant btw. - while the name suggests "with invariant" you don't actually
> check for that.  But again, given canonicalization rules the invariant will be rhs2
> so above add
> 
>         && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST
> 
> for example.
> 
> >  /* n - (((n > C1) ? n : C1) & -C2) ->  n & C1 for unsigned case.
> >     n - (((n > C1) ? n : C1) & -C2) ->  (n <= C1) ? n : (n & C1) for
> > signed case.  */  (simplify diff --git
> > a/gcc/testsuite/gcc.target/i386/pr105735-1.c
> > b/gcc/testsuite/gcc.target/i386/pr105735-1.c
> > new file mode 100644
> > index 00000000000..8d2123ed351
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr105735-1.c
> > @@ -0,0 +1,88 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O1 -fdump-tree-sccp-details" } */
> > +/* { dg-final { scan-tree-dump-times {final value replacement} 8 "sccp"
> > +} } */
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +foo (unsigned long long tmp, unsigned long long bit2) {
> 
> you probably need dg-require-effective-target longlong, but is it necessary to
> use long long for the testcases in the first place?
> The IV seems to be unused, if it should match the variables bit size use sizeof
> (type) * 8
> 
> > +  for (int bit = 0; bit < 64; bit++)
> > +    tmp &= bit2;
> > +  return tmp;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +foo1 (unsigned long long tmp, unsigned long long bit2) {
> > +  for (int bit = 63; bit >= 0; bit -=3)
> > +    tmp &= bit2;
> > +  return tmp;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +foo2 (unsigned long long tmp, unsigned long long bit2) {
> > +  for (int bit = 0; bit < 64; bit++)
> > +    tmp |= bit2;
> > +  return tmp;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +foo3 (unsigned long long tmp, unsigned long long bit2) {
> > +  for (int bit = 63; bit >= 0; bit -=3)
> > +    tmp |= bit2;
> > +  return tmp;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +foo4 (unsigned long long tmp, unsigned long long bit2) {
> > +  for (int bit = 0; bit < 64; bit++)
> > +    tmp ^= bit2;
> > +  return tmp;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +foo5 (unsigned long long tmp, unsigned long long bit2) {
> > +  for (int bit = 0; bit < 63; bit++)
> > +    tmp ^= bit2;
> > +  return tmp;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +f (unsigned long long tmp, long long bit, unsigned long long bit2) {
> > +  unsigned long long res = tmp;
> > +  for (long long i = 0; i < bit; i++)
> > +    res &= bit2;
> > +  return res;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +f1 (unsigned long long tmp, long long bit, unsigned long long bit2) {
> > +  unsigned long long res = tmp;
> > +  for (long long i = 0; i < bit; i++)
> > +    res |= bit2;
> > +  return res;
> > +}
> > +
> > +unsigned long long
> > +__attribute__((noipa))
> > +f2 (unsigned long long tmp, long long bit, unsigned long long bit2) {
> > +  unsigned long long res = tmp;
> > +  for (long long i = 0; i < bit; i++)
> > +    res ^= bit2;
> > +  return res;
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.target/i386/pr105735-2.c
> > b/gcc/testsuite/gcc.target/i386/pr105735-2.c
> > new file mode 100644
> > index 00000000000..79c1d300b1b
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr105735-2.c
> > @@ -0,0 +1,28 @@
> > +/* { dg-do run } */
> > +/* { dg-options "-O1" } */
> > +
> > +#include "pr105735-1.c"
> > +
> > +int main()
> > +{
> > +  unsigned long long tmp = 0x1101101ULL;
> > +  unsigned long long bit2 = 0x1111111011110111ULL;
> > +  if (foo (tmp, bit2) != 0x1100101ULL)
> > +    __builtin_abort ();
> > +  if (foo1 (tmp, bit2) != 0x1100101ULL)
> > +    __builtin_abort ();
> > +  if (foo2 (tmp, bit2) != 0x1111111011111111ULL)
> > +    __builtin_abort ();
> > +  if (foo3 (tmp, bit2) != 0x1111111011111111ULL)
> > +    __builtin_abort ();
> > +  if (foo4 (tmp, bit2) != 0x1101101ULL)
> > +    __builtin_abort ();
> > +  if (foo5 (tmp, bit2) != 0x1111111010011010ULL)
> > +    __builtin_abort ();
> > +  if (f (tmp, 64, bit2) != 0x1100101ULL)
> > +    __builtin_abort ();
> > +  if (f1 (tmp, 64, bit2) != 0x1111111011111111ULL)
> > +    __builtin_abort ();
> > +  if (f2 (tmp, 64, bit2) != 0x1101101ULL)
> > +    __builtin_abort ();
> > +}
> > diff --git a/gcc/tree-scalar-evolution.cc
> > b/gcc/tree-scalar-evolution.cc index fc59d035b19..81220f08d2e 100644
> > --- a/gcc/tree-scalar-evolution.cc
> > +++ b/gcc/tree-scalar-evolution.cc
> > @@ -3635,6 +3635,53 @@ enum bit_op_kind
> >    return fold_build2 (code1, type, inv, wide_int_to_tree (type,
> > bits));  }
> >
> > +/* Match.pd function to match bitop with invariant expression
> > +  .i.e.
> > +  tmp_7 = _0 & _1; */
> > +extern bool gimple_bitop_with_inv_p (tree, tree *, tree (*)(tree));
> > +
> > +/* Return the inductive expression of bitop with invariant if possible,
> > +   otherwise returns DEF.  */
> > +static tree
> > +analyze_and_compute_bitop_with_inv_effect (class loop* loop, tree phidef,
> > +                                          tree niter) {
> > +  tree match_op[2],inv;
> > +  tree type = TREE_TYPE (phidef);
> > +  gphi* header_phi = NULL;
> > +  /* match thing like op0 (match[0]), op1(match[1]), phidef(PHIDEF)
> > +
> > +    op1 =  PHI <phidef, inv>
> > +    phidef = op0 & op1
> > +    if op0 is an invariant, it could change to
> > +    phidef = op0 & inv.  */
> > +  if (!gimple_bitop_with_inv_p (phidef, &match_op[0], NULL)
> > +      || TREE_CODE (match_op[1]) != SSA_NAME
> > +      || !expr_invariant_in_loop_p (loop, match_op[0])
> > +      || !(header_phi = dyn_cast <gphi *> (SSA_NAME_DEF_STMT
> (match_op[1])))
> > +      || gimple_phi_num_args (header_phi) != 2)
> > +    return NULL_TREE;
> > +
> > +  if (PHI_ARG_DEF_FROM_EDGE (header_phi, loop_latch_edge (loop)) !=
> phidef)
> > +    return NULL_TREE;
> > +
> > +  enum tree_code code1
> > +    = gimple_assign_rhs_code (SSA_NAME_DEF_STMT (phidef));
> > +
> > +  if (code1 == BIT_XOR_EXPR)
> > +    {
> > +       if (!tree_fits_uhwi_p (niter))
> > +       return NULL_TREE;
> > +       unsigned HOST_WIDE_INT niter_num;
> > +       niter_num = tree_to_uhwi (niter);
> > +       if (niter_num % 2 != 0)
> > +       match_op[0] =  build_zero_cst (type);
> > +    }
> > +
> > +  inv = PHI_ARG_DEF_FROM_EDGE (header_phi, loop_preheader_edge
> > + (loop));  return fold_build2 (code1, type, inv, match_op[0]); }
> 
> The } goes to the next line.
> 
> > +
> >  /* Do final value replacement for LOOP, return true if we did
> > anything.  */
> >
> >  bool
> > @@ -3687,6 +3734,18 @@ final_value_replacement_loop (class loop *loop)
> >                                               &folded_casts);
> >        def = compute_overall_effect_of_inner_loop (ex_loop, def);
> >
> > +      /* Handle bitop with invariant induction expression.
> > +
> > +       .i.e
> > +       for (int i =0 ;i < 32; i++)
> > +         tmp &= bit2;
> > +       if bit2 is an invariant in loop which could simple to
> > +       tmp &= bit2.  */
> > +      tree bitinv_def;
> > +      if ((bitinv_def
> 
> please use else if here
> 
> otherwise looks OK.
> 
> > +          = analyze_and_compute_bitop_with_inv_effect (loop, phidef, niter)))
> > +       def = bitinv_def;
> > +
> >        /* Handle bitwise induction expression.
> >
> >          .i.e.
> > --
> > 2.18.2
> >

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From df3b32abaf6fde1afde190a7db781b465baaa2a7 Mon Sep 17 00:00:00 2001
From: konglin1 <lingling.kong@intel.com>
Date: Mon, 1 Aug 2022 17:48:05 +0800
Subject: [PATCH] Enhance final_value_replacement_loop to handle bitop with an
 invariant induction.

This patch will enable below optimization:

{
-  long unsigned int bit;
-
-  <bb 2> [local count: 32534376]:
-
-  <bb 3> [local count: 1041207449]:
-  # tmp_10 = PHI <tmp_7(5), tmp_4(D)(2)>
-  # bit_12 = PHI <bit_8(5), 0(2)>
-  tmp_7 = bit2_6(D) & tmp_10;
-  bit_8 = bit_12 + 1;
-  if (bit_8 != 32)
-    goto <bb 5>; [96.97%]
-  else
-    goto <bb 4>; [3.03%]
-
-  <bb 5> [local count: 1009658865]:
-  goto <bb 3>; [100.00%]
-
-  <bb 4> [local count: 32534376]:
-  # tmp_11 = PHI <tmp_7(3)>
-  return tmp_11;
+  tmp_11 = tmp_4 (D) & bit2_6 (D);
+  return tmp_11;

}

gcc/ChangeLog:

	PR middle-end/105735
	* tree-scalar-evolution.cc
	(analyze_and_compute_bitop_with_inv_effect): New function.
	(final_value_replacement_loop): Enhanced to handle bitop
	with inv induction.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr105735-1.c: New test.
	* gcc.target/i386/pr105735-2.c: New test.
---
 gcc/testsuite/gcc.target/i386/pr105735-1.c | 88 ++++++++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr105735-2.c | 28 +++++++
 gcc/tree-scalar-evolution.cc               | 70 +++++++++++++++++
 3 files changed, 186 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr105735-1.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr105735-2.c

diff --git a/gcc/testsuite/gcc.target/i386/pr105735-1.c b/gcc/testsuite/gcc.target/i386/pr105735-1.c
new file mode 100644
index 00000000000..69de6b2911a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr105735-1.c
@@ -0,0 +1,88 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-sccp-details" } */
+/* { dg-final { scan-tree-dump-times {final value replacement} 8 "sccp" } } */
+
+unsigned int
+__attribute__((noipa))
+foo (unsigned int tmp, unsigned int bit2)
+{
+  for (int bit = 0; bit < 64; bit++)
+    tmp &= bit2;
+  return tmp;
+}
+
+unsigned int
+__attribute__((noipa))
+foo1 (unsigned int tmp, unsigned int bit2)
+{
+  for (int bit = 63; bit >= 0; bit -=3)
+    tmp &= bit2;
+  return tmp;
+}
+
+unsigned int
+__attribute__((noipa))
+foo2 (unsigned int tmp, unsigned int bit2)
+{
+  for (int bit = 0; bit < 64; bit++)
+    tmp |= bit2;
+  return tmp;
+}
+
+unsigned int
+__attribute__((noipa))
+foo3 (unsigned int tmp, unsigned int bit2)
+{
+  for (int bit = 63; bit >= 0; bit -=3)
+    tmp |= bit2;
+  return tmp;
+}
+
+unsigned int
+__attribute__((noipa))
+foo4 (unsigned int tmp, unsigned int bit2)
+{
+  for (int bit = 0; bit < 64; bit++)
+    tmp ^= bit2;
+  return tmp;
+}
+
+unsigned int
+__attribute__((noipa))
+foo5 (unsigned int tmp, unsigned int bit2)
+{
+  for (int bit = 0; bit < 63; bit++)
+    tmp ^= bit2;
+  return tmp;
+}
+
+unsigned int
+__attribute__((noipa))
+f (unsigned int tmp, int bit, unsigned int bit2)
+{
+  unsigned int res = tmp;
+  for (int i = 0; i < bit; i++)
+    res &= bit2;
+  return res;
+}
+
+unsigned int
+__attribute__((noipa))
+f1 (unsigned int tmp, int bit, unsigned int bit2)
+{
+  unsigned int res = tmp;
+  for (int i = 0; i < bit; i++)
+    res |= bit2;
+  return res;
+}
+
+unsigned int
+__attribute__((noipa))
+f2 (unsigned int tmp, int bit, unsigned int bit2)
+{
+  unsigned int res = tmp;
+  for (int i = 0; i < bit; i++)
+    res ^= bit2;
+  return res;
+}
+
diff --git a/gcc/testsuite/gcc.target/i386/pr105735-2.c b/gcc/testsuite/gcc.target/i386/pr105735-2.c
new file mode 100644
index 00000000000..66cc5fba1e7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr105735-2.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O1" } */
+
+#include "pr105735-1.c"
+
+int main()
+{
+  unsigned int tmp = 0x1101;
+  unsigned int bit2 = 0x111101;
+  if (foo (tmp, bit2) != 0x1101)
+    __builtin_abort (); 
+  if (foo1 (tmp, bit2) != 0x1101)
+    __builtin_abort ();
+  if (foo2 (tmp, bit2) != 0x111101)
+    __builtin_abort ();
+  if (foo3 (tmp, bit2) != 0x111101)
+    __builtin_abort ();
+  if (foo4 (tmp, bit2) != 0x1101)
+    __builtin_abort ();
+  if (foo5 (tmp, bit2) != 0x110000)
+    __builtin_abort ();
+  if (f (tmp, 64, bit2) != 0x1101)
+    __builtin_abort ();
+  if (f1 (tmp, 64, bit2) != 0x111101)
+    __builtin_abort ();
+  if (f2 (tmp, 64, bit2) != 0x1101)
+    __builtin_abort ();
+}
diff --git a/gcc/tree-scalar-evolution.cc b/gcc/tree-scalar-evolution.cc
index fc59d035b19..2e5ac7f5792 100644
--- a/gcc/tree-scalar-evolution.cc
+++ b/gcc/tree-scalar-evolution.cc
@@ -3635,6 +3635,64 @@ enum bit_op_kind
   return fold_build2 (code1, type, inv, wide_int_to_tree (type, bits));
 }
 
+/* Match.pd function to match bitop with invariant expression
+  .i.e.
+  tmp_7 = _0 & _1; */
+extern bool gimple_bitop_with_inv_p (tree, tree *, tree (*)(tree));
+
+/* Return the inductive expression of bitop with invariant if possible,
+   otherwise returns DEF.  */
+static tree
+analyze_and_compute_bitop_with_inv_effect (class loop* loop, tree phidef,
+					   tree niter)
+{
+  tree match_op[2],inv;
+  tree type = TREE_TYPE (phidef);
+  gphi* header_phi = NULL;
+  enum tree_code code;
+  /* match thing like op0 (match[0]), op1 (match[1]), phidef (PHIDEF)
+
+    op1 =  PHI <phidef, inv>
+    phidef = op0 & op1
+    if op0 is an invariant, it could change to
+    phidef = op0 & inv.  */
+  gimple *def;
+  def = SSA_NAME_DEF_STMT (phidef);
+  if (!(is_gimple_assign (def)
+      && ((code = gimple_assign_rhs_code (def)), true)
+      && (code == BIT_AND_EXPR || code == BIT_IOR_EXPR
+	  || code == BIT_XOR_EXPR)))
+    return NULL_TREE;
+
+  match_op[0] = gimple_assign_rhs1 (def);
+  match_op[1] = gimple_assign_rhs2 (def);
+
+  if (TREE_CODE (match_op[1]) != SSA_NAME
+      || !expr_invariant_in_loop_p (loop, match_op[0])
+      || !(header_phi = dyn_cast <gphi *> (SSA_NAME_DEF_STMT (match_op[1])))
+      || gimple_phi_num_args (header_phi) != 2)
+    return NULL_TREE;
+
+  if (PHI_ARG_DEF_FROM_EDGE (header_phi, loop_latch_edge (loop)) != phidef)
+    return NULL_TREE;
+
+  enum tree_code code1
+    = gimple_assign_rhs_code (def);
+
+  if (code1 == BIT_XOR_EXPR)
+    {
+       if (!tree_fits_uhwi_p (niter))
+	return NULL_TREE;
+       unsigned HOST_WIDE_INT niter_num;
+       niter_num = tree_to_uhwi (niter);
+       if (niter_num % 2 != 0)
+	match_op[0] =  build_zero_cst (type);
+    }
+
+  inv = PHI_ARG_DEF_FROM_EDGE (header_phi, loop_preheader_edge (loop));
+  return fold_build2 (code1, type, inv, match_op[0]);
+}
+
 /* Do final value replacement for LOOP, return true if we did anything.  */
 
 bool
@@ -3687,6 +3745,18 @@ final_value_replacement_loop (class loop *loop)
 					      &folded_casts);
       def = compute_overall_effect_of_inner_loop (ex_loop, def);
 
+      /* Handle bitop with invariant induction expression.
+
+	.i.e
+	for (int i =0 ;i < 32; i++)
+	  tmp &= bit2;
+	if bit2 is an invariant in loop which could simple to
+	tmp &= bit2.  */
+      tree bitinv_def;
+      if ((bitinv_def
+	   = analyze_and_compute_bitop_with_inv_effect (loop, phidef, niter)))
+	def = bitinv_def;
+
       /* Handle bitwise induction expression.
 
 	 .i.e.
-- 
2.18.2