Re: Remove redundant AND from count reduction loop

[Richard Sandiford <richard.sandiford@arm.com>]

Richard Biener <richard.guenther@gmail.com> writes:
> On Thu, Jun 25, 2015 at 10:15 AM, Richard Sandiford
>> Index: gcc/match.pd
>> ===================================================================
>> --- gcc/match.pd        2015-06-24 20:24:31.344998571 +0100
>> +++ gcc/match.pd        2015-06-24 20:24:31.340998617 +0100
>> @@ -1014,6 +1014,26 @@ along with GCC; see the file COPYING3.
>>    (cnd (logical_inverted_value truth_valued_p@0) @1 @2)
>>    (cnd @0 @2 @1)))
>>
>> +/* A + (B vcmp C ? 1 : 0) -> A - (B vcmp C), since vector comparisons
>> +   return all-1 or all-0 results.  */
>> +/* ??? We could instead convert all instances of the vec_cond to negate,
>> +   but that isn't necessarily a win on its own.  */
>> +(simplify
>> + (plus:c @3 (view_convert? (vec_cond @0 integer_each_onep@1 integer_zerop@2)))
>> + (if (VECTOR_TYPE_P (type)
>> +      && TYPE_VECTOR_SUBPARTS (type) == TYPE_VECTOR_SUBPARTS (TREE_TYPE (@0))
>> +      && (TYPE_MODE (TREE_TYPE (type))
>> +          == TYPE_MODE (TREE_TYPE (TREE_TYPE (@0)))))
>> +  (minus @3 (view_convert @0))))
>> +
>> +/* ... likewise A - (B vcmp C ? 1 : 0) -> A + (B vcmp C).  */
>> +(simplify
>> + (minus @3 (view_convert? (vec_cond @0 integer_each_onep@1 integer_zerop@2)))
>> + (if (VECTOR_TYPE_P (type)
>> +      && TYPE_VECTOR_SUBPARTS (type) == TYPE_VECTOR_SUBPARTS (TREE_TYPE (@0))
>> +      && (TYPE_PRECISION (TREE_TYPE (type))
>> +          == TYPE_PRECISION (TREE_TYPE (TREE_TYPE (@0)))))
>
> Either TYPE_PRECISION or TYPE_MODE please ;)

Bah.  The main reason I hate cut-&-paste is that I'm so hopeless at it.

> I think that TYPE_MODE is more correct if you consider (minus V4SF
> (view_convert:V4SF (vec_cond V4SI V4SI V4SI)) where you would end up
> with a non-sensical TYPE_PRECISION query on V4SF.  So probably
> VECTOR_INTEGER_TYPE_P again, then TYPE_PRECISION is good.

Actually, they were both meant to be TYPE_MODE, as below.  Is this OK?

Thanks,
Richard


gcc/
	* match.pd: Add patterns for vec_conds between 1 and 0.

gcc/testsuite/
	* gcc.target/aarch64/vect-add-sub-cond.c: New test.

Index: gcc/match.pd
===================================================================
--- gcc/match.pd	2015-06-25 11:06:50.462827031 +0100
+++ gcc/match.pd	2015-06-25 11:07:23.742445798 +0100
@@ -1014,6 +1014,26 @@ along with GCC; see the file COPYING3.
   (cnd (logical_inverted_value truth_valued_p@0) @1 @2)
   (cnd @0 @2 @1)))
 
+/* A + (B vcmp C ? 1 : 0) -> A - (B vcmp C), since vector comparisons
+   return all-1 or all-0 results.  */
+/* ??? We could instead convert all instances of the vec_cond to negate,
+   but that isn't necessarily a win on its own.  */
+(simplify
+ (plus:c @3 (view_convert? (vec_cond @0 integer_each_onep@1 integer_zerop@2)))
+ (if (VECTOR_TYPE_P (type)
+      && TYPE_VECTOR_SUBPARTS (type) == TYPE_VECTOR_SUBPARTS (TREE_TYPE (@0))
+      && (TYPE_MODE (TREE_TYPE (type))
+          == TYPE_MODE (TREE_TYPE (TREE_TYPE (@0)))))
+  (minus @3 (view_convert @0))))
+
+/* ... likewise A - (B vcmp C ? 1 : 0) -> A + (B vcmp C).  */
+(simplify
+ (minus @3 (view_convert? (vec_cond @0 integer_each_onep@1 integer_zerop@2)))
+ (if (VECTOR_TYPE_P (type)
+      && TYPE_VECTOR_SUBPARTS (type) == TYPE_VECTOR_SUBPARTS (TREE_TYPE (@0))
+      && (TYPE_MODE (TREE_TYPE (type))
+          == TYPE_MODE (TREE_TYPE (TREE_TYPE (@0)))))
+  (plus @3 (view_convert @0))))
 
 /* Simplifications of comparisons.  */
 
Index: gcc/testsuite/gcc.target/aarch64/vect-add-sub-cond.c
===================================================================
--- /dev/null	2015-06-02 17:27:28.541944012 +0100
+++ gcc/testsuite/gcc.target/aarch64/vect-add-sub-cond.c	2015-06-25 11:06:50.458827055 +0100
@@ -0,0 +1,94 @@
+/* Make sure that vector comaprison results are not unnecessarily ANDed
+   with vectors of 1.  */
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-vectorize" } */
+
+#define COUNT1(X) if (X) count += 1
+#define COUNT2(X) if (X) count -= 1
+#define COUNT3(X) count += (X)
+#define COUNT4(X) count -= (X)
+
+#define COND1(X) (X)
+#define COND2(X) ((X) ? 1 : 0)
+#define COND3(X) ((X) ? -1 : 0)
+#define COND4(X) ((X) ? 0 : 1)
+#define COND5(X) ((X) ? 0 : -1)
+
+#define TEST_LT(X, Y) ((X) < (Y))
+#define TEST_LE(X, Y) ((X) <= (Y))
+#define TEST_GT(X, Y) ((X) > (Y))
+#define TEST_GE(X, Y) ((X) >= (Y))
+#define TEST_EQ(X, Y) ((X) == (Y))
+#define TEST_NE(X, Y) ((X) != (Y))
+
+#define COUNT_LOOP(ID, TYPE, CMP_ARRAY, TEST, COUNT) \
+  TYPE \
+  reduc_##ID (__typeof__ (CMP_ARRAY[0]) x) \
+  { \
+    TYPE count = 0; \
+    for (unsigned int i = 0; i < 1024; ++i) \
+      COUNT (TEST (CMP_ARRAY[i], x)); \
+    return count; \
+  }
+
+#define COND_LOOP(ID, ARRAY, CMP_ARRAY, TEST, COND) \
+  void \
+  plus_##ID (__typeof__ (CMP_ARRAY[0]) x) \
+  { \
+    for (unsigned int i = 0; i < 1024; ++i) \
+      ARRAY[i] += COND (TEST (CMP_ARRAY[i], x)); \
+  } \
+  void \
+  plusc_##ID (void) \
+  { \
+    for (unsigned int i = 0; i < 1024; ++i) \
+      ARRAY[i] += COND (TEST (CMP_ARRAY[i], 10)); \
+  } \
+  void \
+  minus_##ID (__typeof__ (CMP_ARRAY[0]) x) \
+  { \
+    for (unsigned int i = 0; i < 1024; ++i) \
+      ARRAY[i] -= COND (TEST (CMP_ARRAY[i], x)); \
+  } \
+  void \
+  minusc_##ID (void) \
+  { \
+    for (unsigned int i = 0; i < 1024; ++i) \
+      ARRAY[i] += COND (TEST (CMP_ARRAY[i], 1)); \
+  }
+
+#define ALL_LOOPS(ID, ARRAY, CMP_ARRAY, TEST) \
+  typedef __typeof__(ARRAY[0]) ID##_type; \
+  COUNT_LOOP (ID##_1, ID##_type, CMP_ARRAY, TEST, COUNT1) \
+  COUNT_LOOP (ID##_2, ID##_type, CMP_ARRAY, TEST, COUNT2) \
+  COUNT_LOOP (ID##_3, ID##_type, CMP_ARRAY, TEST, COUNT3) \
+  COUNT_LOOP (ID##_4, ID##_type, CMP_ARRAY, TEST, COUNT4) \
+  COND_LOOP (ID##_1, ARRAY, CMP_ARRAY, TEST, COND1) \
+  COND_LOOP (ID##_2, ARRAY, CMP_ARRAY, TEST, COND2) \
+  COND_LOOP (ID##_3, ARRAY, CMP_ARRAY, TEST, COND3) \
+  COND_LOOP (ID##_4, ARRAY, CMP_ARRAY, TEST, COND4) \
+  COND_LOOP (ID##_5, ARRAY, CMP_ARRAY, TEST, COND5)
+
+signed int asi[1024] __attribute__ ((aligned (16)));
+unsigned int aui[1024] __attribute__ ((aligned (16)));
+signed long long asl[1024] __attribute__ ((aligned (16)));
+unsigned long long aul[1024] __attribute__ ((aligned (16)));
+float af[1024] __attribute__ ((aligned (16)));
+double ad[1024] __attribute__ ((aligned (16)));
+
+ALL_LOOPS (si_si, aui, asi, TEST_LT)
+ALL_LOOPS (ui_si, aui, asi, TEST_LE)
+ALL_LOOPS (si_ui, aui, asi, TEST_GT)
+ALL_LOOPS (ui_ui, aui, asi, TEST_GE)
+ALL_LOOPS (sl_sl, asl, asl, TEST_NE)
+ALL_LOOPS (ul_ul, aul, aul, TEST_EQ)
+ALL_LOOPS (si_f, asi, af, TEST_LE)
+ALL_LOOPS (ui_f, aui, af, TEST_GT)
+ALL_LOOPS (sl_d, asl, ad, TEST_GE)
+ALL_LOOPS (ul_d, aul, ad, TEST_GT)
+
+/* { dg-final { scan-assembler-not "\tand\t" } } */
+/* { dg-final { scan-assembler-not "\tld\[^\t\]*\t\[wx\]" } } */
+/* { dg-final { scan-assembler-not "\tst\[^\t\]*\t\[wx\]" } } */
+/* { dg-final { scan-assembler "\tldr\tq" } } */
+/* { dg-final { scan-assembler "\tstr\tq" } } */