[PATCH] PR tree-optimization/68413 : Only check for integer cond reduction on analysis stage

[PATCH] PR tree-optimization/68413 : Only check for integer cond reduction on analysis stage

[Alan Hayward]

[-- Attachment #1: Type: text/plain, Size: 676 bytes --]

When vectorising a integer induction condition reduction,
is_nonwrapping_integer_induction ends up with different values for base
during the analysis and build phases. In the first it is an INTEGER_CST,
in the second the loop has been vectorised out and the base is now a
variable.

This results in the analysis and build stage detecting the
STMT_VINFO_VEC_REDUCTION_TYPE as different types.

The easiest way to fix this is to only check for integer induction
conditions on the analysis stage.


gcc/
	PR tree-optimization/68413
	* tree-vect-loop.c (vectorizable_reduction): Only check for
	integer cond reduction on analysis stage.




Thanks,
Alan.


[-- Attachment #2: analysisonlycondcheck.patch --]
[-- Type: application/octet-stream, Size: 2930 bytes --]

diff --git a/gcc/testsuite/gcc.dg/vect/pr65947-1.c b/gcc/testsuite/gcc.dg/vect/pr65947-1.c
index 1e7a05dc8cc6f00fee265b9b8ad65beaa520f1e8..09fb6a5b446bac66e6509c704827231b10bec569 100644
--- a/gcc/testsuite/gcc.dg/vect/pr65947-1.c
+++ b/gcc/testsuite/gcc.dg/vect/pr65947-1.c
@@ -37,4 +37,4 @@ main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "LOOP VECTORIZED" 2 "vect" { xfail { ! vect_max_reduc } } } } */
-/* { dg-final { scan-tree-dump-times "condition expression based on integer induction." 4 "vect" { xfail { ! vect_max_reduc } } } } */
+/* { dg-final { scan-tree-dump-times "condition expression based on integer induction." 2 "vect" { xfail { ! vect_max_reduc } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/pr65947-4.c b/gcc/testsuite/gcc.dg/vect/pr65947-4.c
index f4e7fdc97c89866b19838593cb84fc1754f87494..73ce780c08114b929f970afdc8d262efb8960562 100644
--- a/gcc/testsuite/gcc.dg/vect/pr65947-4.c
+++ b/gcc/testsuite/gcc.dg/vect/pr65947-4.c
@@ -37,5 +37,5 @@ main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "LOOP VECTORIZED" 2 "vect" { xfail { ! vect_max_reduc } } } } */
-/* { dg-final { scan-tree-dump-times "condition expression based on integer induction." 4 "vect" { xfail { ! vect_max_reduc } } } } */
+/* { dg-final { scan-tree-dump-times "condition expression based on integer induction." 2 "vect" { xfail { ! vect_max_reduc } } } } */
 
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 4630c86724e9f5df2b33eee4c60d3e7021b777b9..920dcd0ce5675753942d34db29c836e0e0737c26 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -5418,7 +5418,7 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
           reduc_index = i;
         }
 
-      if (i == 1 && code == COND_EXPR && dt == vect_induction_def
+      if (!vec_stmt && i == 1 && code == COND_EXPR && dt == vect_induction_def
 	  && is_nonwrapping_integer_induction (def_stmt, loop))
 	{
 	  if (dump_enabled_p ())
@@ -5452,14 +5452,20 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
       return false;
     }
 
-  gimple *tmp = vect_is_simple_reduction
-		  (loop_vinfo, reduc_def_stmt,
-		  !nested_cycle, &dummy, false,
-		  &STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info));
+  enum vect_reduction_type v_reduc_type;
+  gimple *tmp = vect_is_simple_reduction (loop_vinfo, reduc_def_stmt,
+					  !nested_cycle, &dummy, false,
+					  &v_reduc_type);
 
-  if (cond_expr_is_nonwrapping_integer_induction
-      && STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) == COND_REDUCTION)
-    STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = INTEGER_INDUC_COND_REDUCTION;
+  if (!vec_stmt)
+    {
+      if (cond_expr_is_nonwrapping_integer_induction
+	  && v_reduc_type == COND_REDUCTION)
+	STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)
+		= INTEGER_INDUC_COND_REDUCTION;
+      else
+	STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = v_reduc_type;
+    }
 
   if (orig_stmt)
     gcc_assert (tmp == orig_stmt

Re: [PATCH] PR tree-optimization/68413 : Only check for integer cond reduction on analysis stage

[Richard Biener]

On Fri, Nov 20, 2015 at 10:24 AM, Alan Hayward <alan.hayward@arm.com> wrote:
> When vectorising a integer induction condition reduction,
> is_nonwrapping_integer_induction ends up with different values for base
> during the analysis and build phases. In the first it is an INTEGER_CST,
> in the second the loop has been vectorised out and the base is now a
> variable.
>
> This results in the analysis and build stage detecting the
> STMT_VINFO_VEC_REDUCTION_TYPE as different types.
>
> The easiest way to fix this is to only check for integer induction
> conditions on the analysis stage.

I don't like this.  For the evolution part we have added
STMT_VINFO_LOOP_PHI_EVOLUTION_PART.  If you now need
the original initial value as well then just save it.

Or if you really want to go with the hack then please do not call
is_nonwrapping_integer_induction with vec_stmt != NULL but
initialize cond_expr_is_nonwrapping_integer_induction from
STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)

The hack also lacks a comment.

Richard.

> gcc/
>         PR tree-optimization/68413
>         * tree-vect-loop.c (vectorizable_reduction): Only check for
>         integer cond reduction on analysis stage.
>
>
>
>
> Thanks,
> Alan.
>

Re: [PATCH] PR tree-optimization/68413 : Only check for integer cond reduction on analysis stage

[Alan Hayward]

[-- Attachment #1: Type: text/plain, Size: 1532 bytes --]



On 20/11/2015 11:00, "Richard Biener" <richard.guenther@gmail.com> wrote:

>On Fri, Nov 20, 2015 at 10:24 AM, Alan Hayward <alan.hayward@arm.com>
>wrote:
>> When vectorising a integer induction condition reduction,
>> is_nonwrapping_integer_induction ends up with different values for base
>> during the analysis and build phases. In the first it is an INTEGER_CST,
>> in the second the loop has been vectorised out and the base is now a
>> variable.
>>
>> This results in the analysis and build stage detecting the
>> STMT_VINFO_VEC_REDUCTION_TYPE as different types.
>>
>> The easiest way to fix this is to only check for integer induction
>> conditions on the analysis stage.
>
>I don't like this.  For the evolution part we have added
>STMT_VINFO_LOOP_PHI_EVOLUTION_PART.  If you now need
>the original initial value as well then just save it.
>
>Or if you really want to go with the hack then please do not call
>is_nonwrapping_integer_induction with vec_stmt != NULL but
>initialize cond_expr_is_nonwrapping_integer_induction from
>STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)
>
>The hack also lacks a comment.
>

Ok. I've gone for a combination of both:

I now cache the base in STMT_VINFO_LOOP_PHI_EVOLUTION_BASE.

I've removed the vec_stmt != NULL checks.

I've moved the call to is_nonwrapping_integer_induction until after the
vect_is_simple_reduction check. I never liked that I had
is_nonwrapping_integer_induction early in the function, and think this
looks better.


Alan.


[-- Attachment #2: analysisonlycondcheck2.patch --]
[-- Type: application/octet-stream, Size: 5319 bytes --]

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 4630c86724e9f5df2b33eee4c60d3e7021b777b9..a2dfd2d07d1214949702b2ccffb7319c05901125 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -790,6 +790,8 @@ vect_analyze_scalar_cycles_1 (loop_vec_info loop_vinfo, struct loop *loop)
 	      dump_generic_expr (MSG_NOTE, TDF_SLIM, access_fn);
               dump_printf (MSG_NOTE, "\n");
 	    }
+	  STMT_VINFO_LOOP_PHI_EVOLUTION_BASE (stmt_vinfo)
+	    = initial_condition_in_loop_num (access_fn, loop->num);
 	  STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_vinfo)
 	    = evolution_part_in_loop_num (access_fn, loop->num);
 	}
@@ -803,6 +805,7 @@ vect_analyze_scalar_cycles_1 (loop_vec_info loop_vinfo, struct loop *loop)
 	  continue;
 	}
 
+      gcc_assert (STMT_VINFO_LOOP_PHI_EVOLUTION_BASE (stmt_vinfo) != NULL_TREE);
       gcc_assert (STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_vinfo) != NULL_TREE);
 
       if (dump_enabled_p ())
@@ -5138,7 +5141,7 @@ static bool
 is_nonwrapping_integer_induction (gimple *stmt, struct loop *loop)
 {
   stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt);
-  tree base = PHI_ARG_DEF_FROM_EDGE (stmt, loop_preheader_edge (loop));
+  tree base = STMT_VINFO_LOOP_PHI_EVOLUTION_BASE (stmt_vinfo);
   tree step = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_vinfo);
   tree lhs_type = TREE_TYPE (gimple_phi_result (stmt));
   widest_int ni, max_loop_value, lhs_max;
@@ -5273,7 +5276,7 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
   tree def0, def1, tem, op0, op1 = NULL_TREE;
   bool first_p = true;
   tree cr_index_scalar_type = NULL_TREE, cr_index_vector_type = NULL_TREE;
-  bool cond_expr_is_nonwrapping_integer_induction = false;
+  gimple *cond_expr_induction_def_stmt = NULL;
 
   /* In case of reduction chain we switch to the first stmt in the chain, but
      we don't update STMT_INFO, since only the last stmt is marked as reduction
@@ -5418,15 +5421,8 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
           reduc_index = i;
         }
 
-      if (i == 1 && code == COND_EXPR && dt == vect_induction_def
-	  && is_nonwrapping_integer_induction (def_stmt, loop))
-	{
-	  if (dump_enabled_p ())
-	    dump_printf_loc (MSG_NOTE, vect_location,
-			     "condition expression based on integer "
-			     "induction.\n");
-	  cond_expr_is_nonwrapping_integer_induction = true;
-	}
+      if (i == 1 && code == COND_EXPR && dt == vect_induction_def)
+	cond_expr_induction_def_stmt = def_stmt;
     }
 
   is_simple_use = vect_is_simple_use (ops[i], loop_vinfo, &def_stmt, &dt, &tem);
@@ -5452,14 +5448,23 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
       return false;
     }
 
-  gimple *tmp = vect_is_simple_reduction
-		  (loop_vinfo, reduc_def_stmt,
-		  !nested_cycle, &dummy, false,
-		  &STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info));
+  enum vect_reduction_type v_reduc_type;
+  gimple *tmp = vect_is_simple_reduction (loop_vinfo, reduc_def_stmt,
+					  !nested_cycle, &dummy, false,
+					  &v_reduc_type);
 
-  if (cond_expr_is_nonwrapping_integer_induction
-      && STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) == COND_REDUCTION)
-    STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = INTEGER_INDUC_COND_REDUCTION;
+  /* If we have a condition reduction, see if we can simplify it further.  */
+  if (v_reduc_type == COND_REDUCTION
+      && cond_expr_induction_def_stmt != NULL
+      && is_nonwrapping_integer_induction (cond_expr_induction_def_stmt, loop))
+    {
+      if (dump_enabled_p ())
+	dump_printf_loc (MSG_NOTE, vect_location,
+			 "condition expression based on integer induction.\n");
+      STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = INTEGER_INDUC_COND_REDUCTION;
+    }
+  else
+   STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = v_reduc_type;
 
   if (orig_stmt)
     gcc_assert (tmp == orig_stmt
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 1b5c95c10f4d1f03f1a68abb1e862a8c708f75c7..b0c84d5e4ad5156ee3bafe9060ba5123e8a96f08 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -518,11 +518,12 @@ typedef struct _stmt_vec_info {
   tree dr_step;
   tree dr_aligned_to;
 
-  /* For loop PHI nodes, the evolution part of it.  This makes sure
+  /* For loop PHI nodes, the base and evolution part of it.  This makes sure
      this information is still available in vect_update_ivs_after_vectorizer
      where we may not be able to re-analyze the PHI nodes evolution as
-     peeling for the prologue loop can make it unanalyzable.  The evolution
-     part is still correct though.  */
+     peeling for the prologue loop can make it unanalyzable.  The base and
+     evolution parts are still correct though.  */
+  tree loop_phi_evolution_base;
   tree loop_phi_evolution_part;
 
   /* Used for various bookkeeping purposes, generally holding a pointer to
@@ -645,6 +646,7 @@ STMT_VINFO_BB_VINFO (stmt_vec_info stmt_vinfo)
 #define STMT_VINFO_GROUP_GAP(S)            (S)->gap
 #define STMT_VINFO_GROUP_SAME_DR_STMT(S)   (S)->same_dr_stmt
 #define STMT_VINFO_GROUPED_ACCESS(S)      ((S)->first_element != NULL && (S)->data_ref_info)
+#define STMT_VINFO_LOOP_PHI_EVOLUTION_BASE(S) (S)->loop_phi_evolution_base
 #define STMT_VINFO_LOOP_PHI_EVOLUTION_PART(S) (S)->loop_phi_evolution_part
 #define STMT_VINFO_MIN_NEG_DIST(S)	(S)->min_neg_dist
 

Re: [PATCH] PR tree-optimization/68413 : Only check for integer cond reduction on analysis stage

[Richard Biener]

On Fri, Nov 20, 2015 at 1:33 PM, Alan Hayward <alan.hayward@arm.com> wrote:
>
>
> On 20/11/2015 11:00, "Richard Biener" <richard.guenther@gmail.com> wrote:
>
>>On Fri, Nov 20, 2015 at 10:24 AM, Alan Hayward <alan.hayward@arm.com>
>>wrote:
>>> When vectorising a integer induction condition reduction,
>>> is_nonwrapping_integer_induction ends up with different values for base
>>> during the analysis and build phases. In the first it is an INTEGER_CST,
>>> in the second the loop has been vectorised out and the base is now a
>>> variable.
>>>
>>> This results in the analysis and build stage detecting the
>>> STMT_VINFO_VEC_REDUCTION_TYPE as different types.
>>>
>>> The easiest way to fix this is to only check for integer induction
>>> conditions on the analysis stage.
>>
>>I don't like this.  For the evolution part we have added
>>STMT_VINFO_LOOP_PHI_EVOLUTION_PART.  If you now need
>>the original initial value as well then just save it.
>>
>>Or if you really want to go with the hack then please do not call
>>is_nonwrapping_integer_induction with vec_stmt != NULL but
>>initialize cond_expr_is_nonwrapping_integer_induction from
>>STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)
>>
>>The hack also lacks a comment.
>>
>
> Ok. I've gone for a combination of both:
>
> I now cache the base in STMT_VINFO_LOOP_PHI_EVOLUTION_BASE.
>
> I've removed the vec_stmt != NULL checks.
>
> I've moved the call to is_nonwrapping_integer_induction until after the
> vect_is_simple_reduction check. I never liked that I had
> is_nonwrapping_integer_induction early in the function, and think this
> looks better.

It looks better but the comment for loop_phi_evolution_base is wrong.
The value is _not_ "correct" after prologue peeling (unless you
update it there to a non-constant expr).  It is conservatively "correct"
for is_nonwrapping_integer_induction though.  Which is why I'd
probably rename it to STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED
to reflect this (and similar to STMT_VINFO_NITERS_UNCHANGED).

Ok with that change.

Thanks,
Richard.

>
> Alan.
>

Re: [PATCH] PR tree-optimization/68413 : Only check for integer cond reduction on analysis stage

[Alan Hayward]

[-- Attachment #1: Type: text/plain, Size: 2246 bytes --]



On 20/11/2015 13:47, "Richard Biener" <richard.guenther@gmail.com> wrote:

>On Fri, Nov 20, 2015 at 1:33 PM, Alan Hayward <alan.hayward@arm.com>
>wrote:
>>
>>
>>On 20/11/2015 11:00, "Richard Biener" <richard.guenther@gmail.com> wrote:
>>
>>>On Fri, Nov 20, 2015 at 10:24 AM, Alan Hayward <alan.hayward@arm.com>
>>>wrote:
>>>>When vectorising a integer induction condition reduction,
>>>>is_nonwrapping_integer_induction ends up with different values for base
>>>>during the analysis and build phases. In the first it is an
>>>>INTEGER_CST,
>>>>in the second the loop has been vectorised out and the base is now a
>>>>variable.
>>>>
>>>>This results in the analysis and build stage detecting the
>>>>STMT_VINFO_VEC_REDUCTION_TYPE as different types.
>>>>
>>>>The easiest way to fix this is to only check for integer induction
>>>>conditions on the analysis stage.
>>>
>>>I don't like this.  For the evolution part we have added
>>>STMT_VINFO_LOOP_PHI_EVOLUTION_PART.  If you now need
>>>the original initial value as well then just save it.
>>>
>>>Or if you really want to go with the hack then please do not call
>>>is_nonwrapping_integer_induction with vec_stmt != NULL but
>>>initialize cond_expr_is_nonwrapping_integer_induction from
>>>STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)
>>>
>>>The hack also lacks a comment.
>>>
>>
>>Ok. I've gone for a combination of both:
>>
>>I now cache the base in STMT_VINFO_LOOP_PHI_EVOLUTION_BASE.
>>
>>I've removed the vec_stmt != NULL checks.
>>
>>I've moved the call to is_nonwrapping_integer_induction until after the
>>vect_is_simple_reduction check. I never liked that I had
>>is_nonwrapping_integer_induction early in the function, and think this
>>looks better.
>
>It looks better but the comment for loop_phi_evolution_base is wrong.
>The value is _not_ "correct" after prologue peeling (unless you
>update it there to a non-constant expr).  It is conservatively "correct"
>for is_nonwrapping_integer_induction though.  Which is why I'd
>probably rename it to STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED
>to reflect this (and similar to STMT_VINFO_NITERS_UNCHANGED).
>
>Ok with that change.

Updated as requested and submitted.

Alan.


[-- Attachment #2: analysisonlycondcheck3.patch --]
[-- Type: application/octet-stream, Size: 5362 bytes --]

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 4630c86724e9f5df2b33eee4c60d3e7021b777b9..e4e77da1e1619c529783e806532751ba74448669 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -790,6 +790,8 @@ vect_analyze_scalar_cycles_1 (loop_vec_info loop_vinfo, struct loop *loop)
 	      dump_generic_expr (MSG_NOTE, TDF_SLIM, access_fn);
               dump_printf (MSG_NOTE, "\n");
 	    }
+	  STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED (stmt_vinfo)
+	    = initial_condition_in_loop_num (access_fn, loop->num);
 	  STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_vinfo)
 	    = evolution_part_in_loop_num (access_fn, loop->num);
 	}
@@ -803,6 +805,8 @@ vect_analyze_scalar_cycles_1 (loop_vec_info loop_vinfo, struct loop *loop)
 	  continue;
 	}
 
+      gcc_assert (STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED (stmt_vinfo)
+		  != NULL_TREE);
       gcc_assert (STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_vinfo) != NULL_TREE);
 
       if (dump_enabled_p ())
@@ -5138,7 +5142,7 @@ static bool
 is_nonwrapping_integer_induction (gimple *stmt, struct loop *loop)
 {
   stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt);
-  tree base = PHI_ARG_DEF_FROM_EDGE (stmt, loop_preheader_edge (loop));
+  tree base = STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED (stmt_vinfo);
   tree step = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_vinfo);
   tree lhs_type = TREE_TYPE (gimple_phi_result (stmt));
   widest_int ni, max_loop_value, lhs_max;
@@ -5273,7 +5277,7 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
   tree def0, def1, tem, op0, op1 = NULL_TREE;
   bool first_p = true;
   tree cr_index_scalar_type = NULL_TREE, cr_index_vector_type = NULL_TREE;
-  bool cond_expr_is_nonwrapping_integer_induction = false;
+  gimple *cond_expr_induction_def_stmt = NULL;
 
   /* In case of reduction chain we switch to the first stmt in the chain, but
      we don't update STMT_INFO, since only the last stmt is marked as reduction
@@ -5418,15 +5422,8 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
           reduc_index = i;
         }
 
-      if (i == 1 && code == COND_EXPR && dt == vect_induction_def
-	  && is_nonwrapping_integer_induction (def_stmt, loop))
-	{
-	  if (dump_enabled_p ())
-	    dump_printf_loc (MSG_NOTE, vect_location,
-			     "condition expression based on integer "
-			     "induction.\n");
-	  cond_expr_is_nonwrapping_integer_induction = true;
-	}
+      if (i == 1 && code == COND_EXPR && dt == vect_induction_def)
+	cond_expr_induction_def_stmt = def_stmt;
     }
 
   is_simple_use = vect_is_simple_use (ops[i], loop_vinfo, &def_stmt, &dt, &tem);
@@ -5452,14 +5449,23 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
       return false;
     }
 
-  gimple *tmp = vect_is_simple_reduction
-		  (loop_vinfo, reduc_def_stmt,
-		  !nested_cycle, &dummy, false,
-		  &STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info));
+  enum vect_reduction_type v_reduc_type;
+  gimple *tmp = vect_is_simple_reduction (loop_vinfo, reduc_def_stmt,
+					  !nested_cycle, &dummy, false,
+					  &v_reduc_type);
 
-  if (cond_expr_is_nonwrapping_integer_induction
-      && STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) == COND_REDUCTION)
-    STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = INTEGER_INDUC_COND_REDUCTION;
+  /* If we have a condition reduction, see if we can simplify it further.  */
+  if (v_reduc_type == COND_REDUCTION
+      && cond_expr_induction_def_stmt != NULL
+      && is_nonwrapping_integer_induction (cond_expr_induction_def_stmt, loop))
+    {
+      if (dump_enabled_p ())
+	dump_printf_loc (MSG_NOTE, vect_location,
+			 "condition expression based on integer induction.\n");
+      STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = INTEGER_INDUC_COND_REDUCTION;
+    }
+  else
+   STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) = v_reduc_type;
 
   if (orig_stmt)
     gcc_assert (tmp == orig_stmt
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 1b5c95c10f4d1f03f1a68abb1e862a8c708f75c7..b5ba3e63c5545d1d4d388b133f22674f1d44ba58 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -518,11 +518,13 @@ typedef struct _stmt_vec_info {
   tree dr_step;
   tree dr_aligned_to;
 
-  /* For loop PHI nodes, the evolution part of it.  This makes sure
+  /* For loop PHI nodes, the base and evolution part of it.  This makes sure
      this information is still available in vect_update_ivs_after_vectorizer
      where we may not be able to re-analyze the PHI nodes evolution as
      peeling for the prologue loop can make it unanalyzable.  The evolution
-     part is still correct though.  */
+     part is still correct after peeling, but the base may have changed from
+     the version here.  */
+  tree loop_phi_evolution_base_unchanged;
   tree loop_phi_evolution_part;
 
   /* Used for various bookkeeping purposes, generally holding a pointer to
@@ -645,6 +647,7 @@ STMT_VINFO_BB_VINFO (stmt_vec_info stmt_vinfo)
 #define STMT_VINFO_GROUP_GAP(S)            (S)->gap
 #define STMT_VINFO_GROUP_SAME_DR_STMT(S)   (S)->same_dr_stmt
 #define STMT_VINFO_GROUPED_ACCESS(S)      ((S)->first_element != NULL && (S)->data_ref_info)
+#define STMT_VINFO_LOOP_PHI_EVOLUTION_BASE_UNCHANGED(S) (S)->loop_phi_evolution_base_unchanged
 #define STMT_VINFO_LOOP_PHI_EVOLUTION_PART(S) (S)->loop_phi_evolution_part
 #define STMT_VINFO_MIN_NEG_DIST(S)	(S)->min_neg_dist