Remove unsafe vec optimization (#234)

The optimization tried to remove a useless call to vec, e.g. replace
vec2(v.xy) with v.xy This is not safe when the argument is not a vec2,
e.g. it's an ivec2.

Fixes #233

Author: laurentlb

src/options.fs

@@ -3,7 +3,7 @@
 open System.IO
 open Argu
 
-let version = "1.3.3" // Shader Minifier version
+let version = "1.3.4" // Shader Minifier version
 let debugMode = false
 
 type OutputFormat =

src/rewriter.fs

@@ -225,12 +225,7 @@ let private simplifyVec constr args =
 
     let args = combineSwizzles args |> List.map useInts
     let args = mergeAllEquals args args
-    match args with
-    | [Dot (_, field) as arg] when field.Length > 1 && isFieldSwizzle field ->
-        // vec3(v.xxy)  =>  v.xxy
-        // However, vec3(v.x) should be preserved.
-        arg
-    | _ -> FunCall (Var constr, args)
+    FunCall (Var constr, args)
 
 let private simplifyExpr (didInline: bool ref) env = function
     | FunCall(Var v, passedArgs) as e when v.ToBeInlined ->

tests/compression_results.log

@@ -1,8 +1,8 @@
 clod.frag...                              8960 => 1545.563
 audio-flight-v2.frag                      4650 =>  902.661
-buoy.frag                                 4239 =>  632.427
+buoy.frag                                 4245 =>  633.229
 controllable-machinery.frag               7773 => 1227.926
-ed-209.frag                               7926 => 1363.748
+ed-209.frag                               7938 => 1360.765
 elevated.hlsl                             3416 =>  603.918
 endeavour.frag                            2661 =>  541.942
 from-the-seas-to-the-stars.frag          14370 => 2345.702
@@ -12,12 +12,12 @@ leizex.frag                               2327 =>  515.566
 lunaquatic.frag                           5231 => 1055.816
 mandelbulb.frag                           2419 =>  546.857
 ohanami.frag                              3292 =>  736.461
-orchard.frag                              5643 => 1034.091
+orchard.frag                              5649 => 1035.594
 oscars_chair.frag                         4653 =>  984.586
 robin.frag                                6343 => 1057.981
 slisesix.frag                             4587 =>  937.138
 terrarium.frag                            3634 =>  747.342
 the_real_party_is_in_your_pocket.frag    12248 => 1815.043
 valley_ball.glsl                          4386 =>  888.496
 yx_long_way_from_home.frag                3030 =>  615.535
-Total: 119302 => 21362.097
+Total: 119326 => 21361.418

tests/real/ed-209.frag.expected

@@ -57,7 +57,7 @@ float sdOctogon(vec2 p,float r)
 {
   const vec3 k=vec3(-.9238795325,.3826834323,.4142135623);
   p=abs(p);
-  p-=2.*min(dot(k.xy,p),0.)*k.xy;
+  p-=2.*min(dot(vec2(k.xy),p),0.)*vec2(k.xy);
   p-=2.*min(dot(vec2(-k.x,k.y),p),0.)*vec2(-k.x,k.y);
   p-=vec2(clamp(p.x,-k.z*r,k.z*r),r);
   return length(p)*sign(p.y);

tests/unit/vectors.frag.expected

@@ -1,8 +1,8 @@
 float swizzles()
 {
   vec2 v1=vec2(1);
-  vec3 v2=v1.xyx,v3=vec3(v1.x,v2.xx);
-  vec4 v4=v1.xxyx,v5=vec4(1,v2.zy,2),v6=vec4(v1.xy,v2.xy);
+  vec3 v2=vec3(v1.xyx),v3=vec3(v1.x,v2.xx);
+  vec4 v4=vec4(v1.xxyx),v5=vec4(1,v2.zy,2),v6=vec4(v1.xy,v2.xy);
   return v1.x+v2.x+v3.x+v4.x+v5.x+v6.x;
 }
 vec4 constructor()