[Beignet] [PATCH] libocl: Directly scalarize built-in with vector input.

[Ruiling Song]

This revert the following commit:
"Re-apply "improve the build performance of vector type built-in function.""
commitId: 06cce8178649759e12a3a353f0550189d371871b.

I finally decide to do this because although below kind of program has less
instructions and less compile-time, but it will also introduce extra memory access,
which would cause bad run-time performance if the loop is not unrolled. If the loop
is unrolled, it would be similar like scalarized version.

OVERLOADABLE float16 func (float16 param0)
{
  union{
    float va[16];
    float16 vv16;
  }uret;
  union{
    float pa[16];
    float16 pv16;
  }usrc0;
  usrc0.pv16 = param0;
  for(int i =0; i < 16; i++)
    uret.va[i] = func(usrc0.pa[i]);
 return uret.vv16;
}

I did some experiment on the affected built-in. I fixed the GPU frequency at 1050,
and increase input data to 862000. The result is like below (obviously the scalarized
version has better performance):

bultin_asinh_float16:
loop version:      200ms
scalarized version: 150ms

builtin_sinh_float16:
loop version:      250ms
scalarized version: 160ms

And also this patch would reduce the generation of large integer. Although we support
large integer legalization, I find sometime it is hard to legalize in very efficient way
like large integer LE/GT.
---
 backend/src/libocl/script/gen_vector.py |   45 +++++--------------------------
 1 file changed, 6 insertions(+), 39 deletions(-)

diff --git a/backend/src/libocl/script/gen_vector.py b/backend/src/libocl/script/gen_vector.py
index 291dd87..ffc573a 100755
--- a/backend/src/libocl/script/gen_vector.py
+++ b/backend/src/libocl/script/gen_vector.py
@@ -289,42 +289,9 @@ class builtinProto():
             formatStr += ';'
             self.append(formatStr)
             return formatStr
-        if self.functionName != 'select' and ptypeSeqs[0] == ptypeSeqs[self.paramCount-1] and ptype[1] > 4:
-            formatStr += '\n{ \n  union{'
-            formatStr = self.append(formatStr, '    {0} va[{1}];'.format(vtype[0], vtype[1]))
-            formatStr = self.append(formatStr, '    {0}{1} vv{2};'.format(vtype[0], vtype[1], vtype[1]))
-            formatStr += '\n  }uret;'
-            formatStr += '\n  union{'
-            formatStr = self.append(formatStr, '    {0} pa[{1}];'.format(ptype[0], ptype[1]))
-            formatStr = self.append(formatStr, '    {0}{1} pv{2};'.format(ptype[0], ptype[1], ptype[1]))
-            formatStr += '\n  }'
-            for n in range(0, self.paramCount):
-              formatStr += 'usrc{0}'.format(n)
-              if n+1 != self.paramCount:
-                formatStr +=', '
-            formatStr += ';'
-
-            for n in range(0, self.paramCount):
-              formatStr = self.append(formatStr, '  usrc{0}.pv{1} = param{2};'.format(n, ptype[1], n))
-            formatStr = self.append(formatStr, '  for(int i =0; i < {0}; i++)'.format(ptype[1]))
-            formatStr += '\n    uret.va[i] = '
-            if self.prefix == 'relational' and self.functionName != 'bitselect' and self.functionName != 'select':
-              formatStr += '-'
-            formatStr += '{0}('.format(self.functionName)
-
-            for n in range(0, self.paramCount):
-              formatStr += 'usrc{0}.pa[i]'.format(n)
-              if n+1 != self.paramCount:
-                formatStr +=', '
-            formatStr += ');'
-            formatStr = self.append(formatStr, ' return uret.vv{0};'.format(vtype[1]))
-            formatStr += '\n}'
-            formatStr = self.append(formatStr)
-            return formatStr
-        else:
-          formatStr = self.append(formatStr, '{{return ({0}{1})('.format(vtype[0], vtype[1]))
-          self.indent = len(formatStr)
-          for j in range(0, vtype[1]):
+        formatStr = self.append(formatStr, '{{return ({0}{1})('.format(vtype[0], vtype[1]))
+        self.indent = len(formatStr)
+        for j in range(0, vtype[1]):
             if (j != 0):
                 formatStr += ','
                 if (j + 1) % 2 == 0:
@@ -359,10 +326,10 @@ class builtinProto():
 
             formatStr += ')'
 
-          formatStr += '); }\n'
-          self.append(formatStr)
+        formatStr += '); }\n'
+        self.append(formatStr)
 
-          return formatStr
+        return formatStr
 
     def output(self):
         for line in self.outputStr:
-- 
1.7.10.4