Simplify a+-b and a--b (#354)

laurentlb · Apr 21, 2024 · d8b025a · d8b025a
1 parent b53f9d9
commit d8b025a
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Showing 4 changed files with 13 additions and 4 deletions.
diff --git a/src/rewriter.fs b/src/rewriter.fs
@@ -113,6 +113,12 @@ module private RewriterImpl =
         | FunCall(Op "-", [Int (i1, su)]) -> Int (-i1, su)
         | FunCall(Op "-", [FunCall(Op "-", [e])]) -> e
         | FunCall(Op "+", [e]) -> e
+        // e1 - - e2 -> e1 + e2
+        | FunCall(Op "-", [e1; FunCall(Op "-", [e2])]) ->
+            FunCall(Op "+", [e1; e2]) |> env.fExpr env
+        // e1 + - e2 -> e1 - e2
+        | FunCall(Op "+", [e1; FunCall(Op "-", [e2])]) ->
+            FunCall(Op "-", [e1; e2]) |> env.fExpr env
 
         | FunCall(Op ",", [e1; FunCall(Op ",", [e2; e3])]) ->
             FunCall(Op ",", [env.fExpr env (FunCall(Op ",", [e1; e2])); e3])

diff --git a/tests/compression_results.log b/tests/compression_results.log
@@ -6,7 +6,7 @@ controllable-machinery.frag               7708 => 1220.329
 ed-209.frag                               7766 => 1341.089
 elevated.hlsl                             3405 =>  603.218
 endeavour.frag                            2605 =>  534.116
-from-the-seas-to-the-stars.frag          14292 => 2328.094
+from-the-seas-to-the-stars.frag          14252 => 2317.681
 frozen-wasteland.frag                     4578 =>  806.452
 kinder_painter.frag                       2865 =>  445.014
 leizex.frag                               2298 =>  510.191
@@ -17,8 +17,8 @@ orchard.frag                              5537 => 1022.773
 oscars_chair.frag                         4651 =>  986.364
 robin.frag                                6295 => 1052.336
 slisesix.frag                             4573 =>  931.855
-terrarium.frag                            3624 =>  745.827
+terrarium.frag                            3611 =>  744.367
 the_real_party_is_in_your_pocket.frag    12111 => 1794.687
 valley_ball.glsl                          4386 =>  888.496
 yx_long_way_from_home.frag                2947 =>  606.406
-Total: 135069 => 23627.076
+Total: 135016 => 23615.203
diff --git a/tests/unit/simplify.expected b/tests/unit/simplify.expected
@@ -1,5 +1,6 @@
 #version 330
 
+int i;
 float bar(float x)
 {
   float a=6.;
@@ -19,7 +20,7 @@ float baz(float a)
   b+=sin(a);
   float c=b+5.;
   c+=sin(b);
-  return-c+-c+c;
+  return-c-c+c;
 }
 out vec3 output;
 void notMain(float x)

diff --git a/tests/unit/simplify.frag b/tests/unit/simplify.frag
@@ -1,5 +1,7 @@
 #version 330
 
+int i;
+
 float bar(float x)
 {
 	float a = x;