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#!/usr/bin/env python
# This example shows how to use LLVM intrinsics.
from llvm.core import *
from llvm.ee import *
# setup a function and a builder
mod = Module.new('test')
functy = Type.function(Type.void(), [])
func = mod.add_function(functy, "showme")
block = func.append_basic_block("entry")
b = Builder.new(block)
# let's do bswap on a 32-bit integer using llvm.bswap
val = Constant.int(Type.int(), 42)
bswap = Function.intrinsic(mod, INTR_BSWAP, [Type.int()])
b.call(bswap, [val])
print mod
# the output is:
#
# ; ModuleID = 'test'
#
# define void @showme() {
# entry:
# call i32 @llvm.bswap.i32( i32 42 ) ; <i32>:0 [#uses=0]
# }
#
# declare i32 @llvm.bswap.i32(i32) nounwind readnone
#
# mysin(x) = sqrt(1.0 - pow(cos(x), 2))
float = Type.float()
mysinty = Type.function( float, [float] )
mysin = mod.add_function(mysinty, "mysin")
block = mysin.append_basic_block("entry")
b = Builder.new(block)
sqrt = Function.intrinsic(mod, INTR_SQRT, [float])
pow = Function.intrinsic(mod, INTR_POWI, [float])
cos = Function.intrinsic(mod, INTR_COS, [float])
mysin.args[0].name = "x"
x = mysin.args[0]
one = Constant.real(float, "1")
cosx = b.call(cos, [x], "cosx")
cos2 = b.call(pow, [cosx, Constant.int(Type.int(), 2)], "cos2")
onemc2 = b.sub(one, cos2, "onemc2")
sin = b.call(sqrt, [onemc2], "sin")
b.ret(sin)
print mod
#
# ; ModuleID = 'test'
#
# define void @showme() {
# entry:
# call i32 @llvm.bswap.i32( i32 42 ) ; <i32>:0 [#uses=0]
# }
#
# declare i32 @llvm.bswap.i32(i32) nounwind readnone
#
# define float @mysin(float %x) {
# entry:
# %cosx = call float @llvm.cos.f32( float %x ) ; <float> [#uses=1]
# %cos2 = call float @llvm.powi.f32( float %cosx, i32 2 ) ; <float> [#uses=1]
# %onemc2 = sub float 1.000000e+00, %cos2 ; <float> [#uses=1]
# %sin = call float @llvm.sqrt.f32( float %onemc2 ) ; <float> [#uses=1]
# ret float %sin
# }
#
# declare float @llvm.sqrt.f32(float) nounwind readnone
#
# declare float @llvm.powi.f32(float, i32) nounwind readnone
#
# declare float @llvm.cos.f32(float) nounwind readnone
#
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