WIP, for gains estimation

src/rewriter.fs

@@ -413,6 +413,27 @@ let private simplifyBlock stmts =
             Some (ForE (Some e, cond, inc, body))
         | (Expr e, While (cond, body)) -> // a=0;while(i<5);  ->  for(a=0;i<5;);
             Some (ForE(Some e, Some cond, None, body))
+        | (Expr (FunCall(Op "=", [Var d1; e1])),
+           Expr (FunCall(Op "=", [Var d2; FunCall(Var func, [Var d3; e2])])))
+           when d1 = d2 && d1 = d3 -> // d=e1;d=f(d,e2);  ->  d=f(e1,e2);
+            // Particularly useful for:  d=min(d,f1());d=min(d,f2());  ->  d=min(min(d,f1()),f2());
+            // conditions to perform the replacement:
+            // [A] d is a local. if it's not, a function call in e2 (or even f) could modify it
+            // [B] d3 must be the only use of d in the FunCall to f
+            // [C] f doesn't take d3 as "out" or "inout".
+            if not (List.contains func.Name ["min"; "max"]) then // takes care of [C]
+                None
+            else
+                let e2UsesD = false//failwith "TODO: visiter e2 savoir s'il utilise d" // [B]
+                if e2UsesD then
+                    None
+                else
+                    let dIsALocal = true//failwith "TODO: savoir si d est une locale, mais pour ça il faut avoir accumulé la liste des decls locales de la fonction en cours" // [A]
+                    if not dIsALocal then
+                        None
+                    else
+                        failwith "les gains sont pas fous en compressé, en fait..."
+                        Some (Expr (FunCall(Op "=", [Var d1; FunCall(Var func, [e1; e2])])))
         | _ -> None)
 
     // Inline inner decl-less blocks. (Presence of decl could lead to redefinitions.)  a();{b();}c();  ->  a();b();c();

tests/compression_results.log

@@ -2,22 +2,22 @@ clod.frag...                              8960 => 1545.563
 audio-flight-v2.frag                      4650 =>  902.661
 buoy.frag                                 4242 =>  632.431
 controllable-machinery.frag               7771 => 1227.917
-ed-209.frag                               7932 => 1361.638
+ed-209.frag                               7916 => 1363.067
 elevated.hlsl                             3416 =>  603.918
 endeavour.frag                            2661 =>  541.942
 from-the-seas-to-the-stars.frag          14367 => 2342.623
 frozen-wasteland.frag                     4609 =>  812.410
-kinder_painter.frag                       2905 =>  450.888
+kinder_painter.frag                       2901 =>  450.835
 leizex.frag                               2327 =>  515.566
 lunaquatic.frag                           5231 => 1055.816
 mandelbulb.frag                           2419 =>  546.857
 ohanami.frag                              3292 =>  736.461
 orchard.frag                              5647 => 1033.964
 oscars_chair.frag                         4651 =>  986.364
-robin.frag                                6343 => 1057.981
+robin.frag                                6327 => 1057.611
 slisesix.frag                             4587 =>  937.138
 terrarium.frag                            3634 =>  747.342
-the_real_party_is_in_your_pocket.frag    12243 => 1814.824
+the_real_party_is_in_your_pocket.frag    12187 => 1823.704
 valley_ball.glsl                          4386 =>  888.496
 yx_long_way_from_home.frag                3030 =>  615.535
-Total: 119303 => 21358.334
+Total: 119211 => 21368.221

tests/real/ed-209.frag.expected

@@ -143,9 +143,7 @@ MarchData gunPod(vec3 p)
   float bump=sign(sin(pp.z*33.3))*.003,d=sdBox(pp,vec3(.1-bump,.38-bump,.34))-.02;
   pp=p-vec3(0,0,-.6);
   pp.x=abs(pp.x)-.1;
-  d=min(d,sdCappedCylinder(pp,.06,.15));
-  d=min(d,sdCappedCylinder(pp+vec3(0,.12,-.05),.06,.05));
-  d=min(d,sdBox(p+vec3(0,0,.54),vec3(.1,.06,.04)));
+  d=min(min(min(d,sdCappedCylinder(pp,.06,.15)),sdCappedCylinder(pp+vec3(0,.12,-.05),.06,.05)),sdBox(p+vec3(0,0,.54),vec3(.1,.06,.04)));
   if(d<r.d)
     d=max(d,-sdCappedCylinder(pp+vec3(0,0,.1),.03,.2)),r.d=d,r.mat=vec3(.02);
   float fs=fireShock();
@@ -277,9 +275,7 @@ MarchData room(vec3 p)
   if(r.d==backWall)
     {
       float ocp;
-      ocp=min(abs(sdOctogon(xy,2.6)),abs(sdOctogon(xy,1.9)));
-      ocp=max(ocp,min(.7-abs(xy.x+1.2),-xy.y));
-      ocp=min(ocp,max(abs(sdOctogon(xy,1.2)),min(xy.x,.7-abs(xy.y))));
+      ocp=min(max(min(abs(sdOctogon(xy,2.6)),abs(sdOctogon(xy,1.9))),min(.7-abs(xy.x+1.2),-xy.y)),max(abs(sdOctogon(xy,1.2)),min(xy.x,.7-abs(xy.y))));
       if(ocp<.3)
         r.mat=vec3(.39,.57,.71);
     }

tests/real/kinder_painter.expected

@@ -138,8 +138,7 @@
    "b=n(z,f,v,m);"
    "d=dot(b,r.xyz);"
    "s.xyz=reflect(y,b);"
-   "i=dot(s.xyz,r.xyz);"
-   "i=max(i,0.);"
+   "i=max(dot(s.xyz,r.xyz),0.);"
    "i*=i;"
    "i*=i;"
    "if(x(v,r.xyz,r.w))"