406 lines
13 KiB
Python
406 lines
13 KiB
Python
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#!/usr/bin/env python
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"""A shuffle-select vector fuzz tester.
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This is a python program to fuzz test the LLVM shufflevector and select
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instructions. It generates a function with a random sequnece of shufflevectors
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while optionally attaching it with a select instruction (regular or zero merge),
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maintaining the element mapping accumulated across the function. It then
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generates a main function which calls it with a different value in each element
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and checks that the result matches the expected mapping.
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Take the output IR printed to stdout, compile it to an executable using whatever
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set of transforms you want to test, and run the program. If it crashes, it found
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a bug (an error message with the expected and actual result is printed).
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"""
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from __future__ import print_function
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import random
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import uuid
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import argparse
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# Possibility of one undef index in generated mask for shufflevector instruction
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SHUF_UNDEF_POS = 0.15
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# Possibility of one undef index in generated mask for select instruction
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SEL_UNDEF_POS = 0.15
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# Possibility of adding a select instruction to the result of a shufflevector
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ADD_SEL_POS = 0.4
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# If we are adding a select instruction, this is the possibility of a
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# merge-select instruction (1 - MERGE_SEL_POS = possibility of zero-merge-select
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# instruction.
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MERGE_SEL_POS = 0.5
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test_template = r'''
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define internal fastcc {ty} @test({inputs}) noinline nounwind {{
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entry:
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{instructions}
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ret {ty} {last_name}
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}}
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'''
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error_template = r'''@error.{lane} = private unnamed_addr global [64 x i8] c"FAIL: lane {lane}, expected {exp}, found %d\0A{padding}"'''
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main_template = r'''
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define i32 @main() {{
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entry:
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; Create a scratch space to print error messages.
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%str = alloca [64 x i8]
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%str.ptr = getelementptr inbounds [64 x i8], [64 x i8]* %str, i32 0, i32 0
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; Build the input vector and call the test function.
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%v = call fastcc {ty} @test({inputs})
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br label %test.0
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{check_die}
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}}
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declare i32 @strlen(i8*)
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declare i32 @write(i32, i8*, i32)
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declare i32 @sprintf(i8*, i8*, ...)
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declare void @llvm.trap() noreturn nounwind
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'''
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check_template = r'''
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test.{lane}:
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%v.{lane} = extractelement {ty} %v, i32 {lane}
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%cmp.{lane} = {i_f}cmp {ordered}ne {scalar_ty} %v.{lane}, {exp}
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br i1 %cmp.{lane}, label %die.{lane}, label %test.{n_lane}
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'''
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undef_check_template = r'''
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test.{lane}:
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; Skip this lane, its value is undef.
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br label %test.{n_lane}
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'''
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die_template = r'''
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die.{lane}:
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; Capture the actual value and print an error message.
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call i32 (i8*, i8*, ...) @sprintf(i8* %str.ptr, i8* getelementptr inbounds ([64 x i8], [64 x i8]* @error.{lane}, i32 0, i32 0), {scalar_ty} %v.{lane})
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%length.{lane} = call i32 @strlen(i8* %str.ptr)
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call i32 @write(i32 2, i8* %str.ptr, i32 %length.{lane})
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call void @llvm.trap()
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unreachable
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'''
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class Type:
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def __init__(self, is_float, elt_width, elt_num):
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self.is_float = is_float # Boolean
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self.elt_width = elt_width # Integer
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self.elt_num = elt_num # Integer
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def dump(self):
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if self.is_float:
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str_elt = 'float' if self.elt_width == 32 else 'double'
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else:
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str_elt = 'i' + str(self.elt_width)
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if self.elt_num == 1:
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return str_elt
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else:
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return '<' + str(self.elt_num) + ' x ' + str_elt + '>'
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def get_scalar_type(self):
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return Type(self.is_float, self.elt_width, 1)
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# Class to represent any value (variable) that can be used.
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class Value:
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def __init__(self, name, ty, value = None):
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self.ty = ty # Type
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self.name = name # String
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self.value = value # list of integers or floating points
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# Class to represent an IR instruction (shuffle/select).
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class Instruction(Value):
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def __init__(self, name, ty, op0, op1, mask):
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Value.__init__(self, name, ty)
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self.op0 = op0 # Value
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self.op1 = op1 # Value
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self.mask = mask # list of integers
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def dump(self): pass
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def calc_value(self): pass
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# Class to represent an IR shuffle instruction
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class ShufInstr(Instruction):
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shuf_template = ' {name} = shufflevector {ty} {op0}, {ty} {op1}, <{num} x i32> {mask}\n'
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def __init__(self, name, ty, op0, op1, mask):
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Instruction.__init__(self, '%shuf' + name, ty, op0, op1, mask)
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def dump(self):
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str_mask = [('i32 ' + str(idx)) if idx != -1 else 'i32 undef' for idx in self.mask]
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str_mask = '<' + (', ').join(str_mask) + '>'
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return self.shuf_template.format(name = self.name, ty = self.ty.dump(), op0 = self.op0.name,
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op1 = self.op1.name, num = self.ty.elt_num, mask = str_mask)
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def calc_value(self):
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if self.value != None:
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print('Trying to calculate the value of a shuffle instruction twice')
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exit(1)
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result = []
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for i in range(len(self.mask)):
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index = self.mask[i]
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if index < self.ty.elt_num and index >= 0:
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result.append(self.op0.value[index])
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elif index >= self.ty.elt_num:
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index = index % self.ty.elt_num
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result.append(self.op1.value[index])
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else: # -1 => undef
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result.append(-1)
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self.value = result
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# Class to represent an IR select instruction
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class SelectInstr(Instruction):
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sel_template = ' {name} = select <{num} x i1> {mask}, {ty} {op0}, {ty} {op1}\n'
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def __init__(self, name, ty, op0, op1, mask):
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Instruction.__init__(self, '%sel' + name, ty, op0, op1, mask)
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def dump(self):
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str_mask = [('i1 ' + str(idx)) if idx != -1 else 'i1 undef' for idx in self.mask]
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str_mask = '<' + (', ').join(str_mask) + '>'
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return self.sel_template.format(name = self.name, ty = self.ty.dump(), op0 = self.op0.name,
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op1 = self.op1.name, num = self.ty.elt_num, mask = str_mask)
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def calc_value(self):
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if self.value != None:
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print('Trying to calculate the value of a select instruction twice')
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exit(1)
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result = []
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for i in range(len(self.mask)):
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index = self.mask[i]
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if index == 1:
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result.append(self.op0.value[i])
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elif index == 0:
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result.append(self.op1.value[i])
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else: # -1 => undef
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result.append(-1)
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self.value = result
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# Returns a list of Values initialized with actual numbers according to the
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# provided type
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def gen_inputs(ty, num):
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inputs = []
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for i in range(num):
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inp = []
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for j in range(ty.elt_num):
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if ty.is_float:
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inp.append(float(i*ty.elt_num + j))
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else:
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inp.append((i*ty.elt_num + j) % (1 << ty.elt_width))
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inputs.append(Value('%inp' + str(i), ty, inp))
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return inputs
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# Returns a random vector type to be tested
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# In case one of the dimensions (scalar type/number of elements) is provided,
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# fill the blank dimension and return appropriate Type object.
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def get_random_type(ty, num_elts):
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if ty != None:
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if ty == 'i8':
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is_float = False
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width = 8
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elif ty == 'i16':
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is_float = False
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width = 16
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elif ty == 'i32':
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is_float = False
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width = 32
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elif ty == 'i64':
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is_float = False
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width = 64
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elif ty == 'f32':
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is_float = True
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width = 32
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elif ty == 'f64':
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is_float = True
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width = 64
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int_elt_widths = [8, 16, 32, 64]
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float_elt_widths = [32, 64]
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if num_elts == None:
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num_elts = random.choice(range(2, 65))
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if ty == None:
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# 1 for integer type, 0 for floating-point
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if random.randint(0,1):
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is_float = False
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width = random.choice(int_elt_widths)
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else:
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is_float = True
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width = random.choice(float_elt_widths)
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return Type(is_float, width, num_elts)
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# Generate mask for shufflevector IR instruction, with SHUF_UNDEF_POS possibility
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# of one undef index.
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def gen_shuf_mask(ty):
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mask = []
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for i in range(ty.elt_num):
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if SHUF_UNDEF_POS/ty.elt_num > random.random():
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mask.append(-1)
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else:
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mask.append(random.randint(0, ty.elt_num*2 - 1))
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return mask
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# Generate mask for select IR instruction, with SEL_UNDEF_POS possibility
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# of one undef index.
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def gen_sel_mask(ty):
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mask = []
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for i in range(ty.elt_num):
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if SEL_UNDEF_POS/ty.elt_num > random.random():
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mask.append(-1)
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else:
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mask.append(random.randint(0, 1))
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return mask
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# Generate shuffle instructions with optional select instruction after.
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def gen_insts(inputs, ty):
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int_zero_init = Value('zeroinitializer', ty, [0]*ty.elt_num)
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float_zero_init = Value('zeroinitializer', ty, [0.0]*ty.elt_num)
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insts = []
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name_idx = 0
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while len(inputs) > 1:
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# Choose 2 available Values - remove them from inputs list.
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[idx0, idx1] = sorted(random.sample(range(len(inputs)), 2))
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op0 = inputs[idx0]
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op1 = inputs[idx1]
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# Create the shuffle instruction.
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shuf_mask = gen_shuf_mask(ty)
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shuf_inst = ShufInstr(str(name_idx), ty, op0, op1, shuf_mask)
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shuf_inst.calc_value()
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# Add the new shuffle instruction to the list of instructions.
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insts.append(shuf_inst)
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# Optionally, add select instruction with the result of the previous shuffle.
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if random.random() < ADD_SEL_POS:
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# Either blending with a random Value or with an all-zero vector.
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if random.random() < MERGE_SEL_POS:
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op2 = random.choice(inputs)
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else:
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op2 = float_zero_init if ty.is_float else int_zero_init
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select_mask = gen_sel_mask(ty)
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select_inst = SelectInstr(str(name_idx), ty, shuf_inst, op2, select_mask)
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select_inst.calc_value()
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# Add the select instructions to the list of instructions and to the available Values.
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insts.append(select_inst)
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inputs.append(select_inst)
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else:
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# If the shuffle instruction is not followed by select, add it to the available Values.
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inputs.append(shuf_inst)
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del inputs[idx1]
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del inputs[idx0]
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name_idx += 1
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return insts
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def main():
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument('--seed', default=str(uuid.uuid4()),
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help='A string used to seed the RNG')
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parser.add_argument('--max-num-inputs', type=int, default=20,
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help='Specify the maximum number of vector inputs for the test. (default: 20)')
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parser.add_argument('--min-num-inputs', type=int, default=10,
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help='Specify the minimum number of vector inputs for the test. (default: 10)')
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parser.add_argument('--type', default=None,
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help='''
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Choose specific type to be tested.
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i8, i16, i32, i64, f32 or f64.
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(default: random)''')
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parser.add_argument('--num-elts', default=None, type=int,
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help='Choose specific number of vector elements to be tested. (default: random)')
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args = parser.parse_args()
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print('; The seed used for this test is ' + args.seed)
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assert args.min_num_inputs < args.max_num_inputs , "Minimum value greater than maximum."
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assert args.type in [None, 'i8', 'i16', 'i32', 'i64', 'f32', 'f64'], "Illegal type."
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assert args.num_elts == None or args.num_elts > 0, "num_elts must be a positive integer."
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random.seed(args.seed)
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ty = get_random_type(args.type, args.num_elts)
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inputs = gen_inputs(ty, random.randint(args.min_num_inputs, args.max_num_inputs))
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inputs_str = (', ').join([inp.ty.dump() + ' ' + inp.name for inp in inputs])
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inputs_values = [inp.value for inp in inputs]
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insts = gen_insts(inputs, ty)
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assert len(inputs) == 1, "Only one value should be left after generating phase"
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res = inputs[0]
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# print the actual test function by dumping the generated instructions.
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insts_str = ''.join([inst.dump() for inst in insts])
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print(test_template.format(ty = ty.dump(), inputs = inputs_str,
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instructions = insts_str, last_name = res.name))
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# Print the error message templates as global strings
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for i in range(len(res.value)):
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pad = ''.join(['\\00']*(31 - len(str(i)) - len(str(res.value[i]))))
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print(error_template.format(lane = str(i), exp = str(res.value[i]),
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padding = pad))
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# Prepare the runtime checks and failure handlers.
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scalar_ty = ty.get_scalar_type()
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check_die = ''
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i_f = 'f' if ty.is_float else 'i'
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ordered = 'o' if ty.is_float else ''
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for i in range(len(res.value)):
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if res.value[i] != -1:
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# Emit runtime check for each non-undef expected value.
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check_die += check_template.format(lane = str(i), n_lane = str(i+1),
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ty = ty.dump(), i_f = i_f, scalar_ty = scalar_ty.dump(),
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exp = str(res.value[i]), ordered = ordered)
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# Emit failure handler for each runtime check with proper error message
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check_die += die_template.format(lane = str(i), scalar_ty = scalar_ty.dump())
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else:
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# Ignore lanes with undef result
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check_die += undef_check_template.format(lane = str(i), n_lane = str(i+1))
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check_die += '\ntest.' + str(len(res.value)) + ':\n'
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check_die += ' ret i32 0'
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# Prepare the input values passed to the test function.
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inputs_values = [', '.join([scalar_ty.dump() + ' ' + str(i) for i in inp]) for inp in inputs_values]
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inputs = ', '.join([ty.dump() + ' <' + inp + '>' for inp in inputs_values])
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print(main_template.format(ty = ty.dump(), inputs = inputs, check_die = check_die))
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if __name__ == '__main__':
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main()
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