The demo can be located here, http://webglsamples.googlecode.com/hg/aquarium/aquarium.html .  The compiler fails to flatten an if statement in a fragment shader containing a discard.

uniform vec4 lightColor;
varying vec4 v_position;
varying vec2 v_texCoord;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;
uniform vec4 ambient;
uniform sampler2D diffuse;
uniform vec4 specular;
uniform float shininess;
uniform float specularFactor;
uniform float fogPower;
uniform float fogMult;
uniform float fogOffset;
uniform vec4 fogColor;
vec4 lit(in float l, in float h, in float m){
return vec4(1.0, max(l, 0.0), (((l > 0.0)) ? (pow(max(0.0, h), m)) : (0.0)), 1.0);
}
void main(){
vec4 diffuseColor = texture2D(diffuse, v_texCoord);
if ((diffuseColor[3] < 0.30000001))
{
discard;
}
vec3 normal = normalize(v_normal);
vec3 surfaceToLight = normalize(v_surfaceToLight);
vec3 surfaceToView = normalize(v_surfaceToView);
vec3 halfVector = normalize((surfaceToLight + surfaceToView));
vec4 litR = lit(dot(normal, surfaceToLight), dot(normal, halfVector), shininess);
vec4 outColor = vec4((lightColor * (((diffuseColor * litR[1]) + (diffuseColor * ambient)) + ((specular * litR[2]) * specularFactor))).xyz, diffuseColor[3]);
(outColor = mix(outColor, vec4(fogColor.xyz, diffuseColor[3]), clamp(((pow((v_position[2] / v_position[3]), fogPower) * fogMult) - fogOffset), 0.0, 1.0)));
(gl_FragColor = outColor);
}

I've attached a full log with INTEL_DEBUG=wm and MESA_GLSL=dump, the shader in question is program 100, shader 102.