Fragment shader working so strange

the fragment shader is working so strange, can someone explain me whats going on.

this one compiles fine but crashes when i use it-

#version 330 core
const float PI = 3.14159265359;
out vec4 coloroutfinal;


in vec3 fragpos;
uniform vec3 lightpos;
uniform vec3 camerapos;


vec3 wi;
vec3 normal;
float cosT;
uniform vec3 lightcolor;
vec3 incidentlight;


uniform float metallic;
uniform float roughness;
uniform vec3 albedo;
uniform float ao;

vec3 fresnel(float cosT,vec3 Fo);
float ND(vec3 H,vec3 N,float roughness);
float G(vec3 L,vec3 N,vec3 V,float roughness);

void main()
{
  coloroutfinal=vec4(1.0);

}


vec3 fresnel(float cosT,vec3 Fo)
{
  return Fo+(1.0-Fo)*pow((1-cosT),5);
}

float ND(vec3 H,vec3 N,float roughness)
{
   float roughness4=pow(roughness,4);
   float cosT=max(dot(N,H),0.0);
   float cosT2=cosT*cosT;
   float num=roughness4;
   float denom=cosT2*(1.0-roughness4)+1.0;
   return num/denom;
}

float GP(float cosT,float roughness)
{
roughness-=1.0;
   float r2=roughness*roughness;
   float k=r2/8;

float num=cosT;
float denom=cosT*(1.0-k)+k;
 return num/denom;

}

float G(vec3 L,vec3 N,vec3 V,float roughness)
{
  float cosTL=max(dot(N,L),0.0);
  float cosTV=max(dot(N,V),0.0);

  float GL=GP(cosTL,roughness);
  float GV=GP(cosTV,roughness);
  return GL*GV;
}

but this one is just the same as above but no function definitions but works fine(renders my object in white)-

#version 330 core
const float PI = 3.14159265359;
out vec4 coloroutfinal;


in vec3 fragpos;
uniform vec3 lightpos;
uniform vec3 camerapos;


vec3 wi;
vec3 normal;
float cosT;
uniform vec3 lightcolor;
vec3 incidentlight;


uniform float metallic;
uniform float roughness;
uniform vec3 albedo;
uniform float ao;

vec3 fresnel(float cosT,vec3 Fo);
float ND(vec3 H,vec3 N,float roughness);
float G(vec3 L,vec3 N,vec3 V,float roughness);

void main()
{
  coloroutfinal=vec4(1.0);

}

I never call the function so how are they interfearing. also both the shaders compile and link fine.

can someone point me to the mistake?