Merge pull request #5427 from smrg-lm/topic/optimization_identity_cases

class library: Fix BinaryOpUGen optimization for a === b cases
supercollider · Aug 21, 2022 · 0f66e76 · 0f66e76
2 parents b106749 + 34f2140
commit 0f66e76
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Showing 2 changed files with 26 additions and 3 deletions.
diff --git a/SCClassLibrary/Common/Audio/BasicOpsUGen.sc b/SCClassLibrary/Common/Audio/BasicOpsUGen.sc
@@ -168,6 +168,7 @@ BinaryOpUGen : BasicOpUGen {
 	optimizeAddNeg {
 		var a, b, replacement;
 		#a, b = inputs;
+		if(a === b) { ^nil };  // non optimizable edge case.
 
 		if (b.isKindOf(UnaryOpUGen) and: { b.operator == 'neg' and: { b.descendants.size == 1 } }) {
 			// a + b.neg -> a - b
@@ -197,6 +198,7 @@ BinaryOpUGen : BasicOpUGen {
 	optimizeToMulAdd {
 		var a, b, replacement;
 		#a, b = inputs;
+		if(a === b) { ^nil };
 
 		if (a.isKindOf(BinaryOpUGen) and: { a.operator == '*'
 			and: { a.descendants.size == 1 }})
@@ -269,6 +271,7 @@ BinaryOpUGen : BasicOpUGen {
 	optimizeToSum4 {
 		var a, b, replacement;
 		#a, b = inputs;
+		if(a === b) { ^nil };
 		if(a.rate == \demand or: { b.rate == \demand }) { ^nil };
 
 		if (a.isKindOf(Sum3) and: { a.descendants.size == 1 }) {

diff --git a/testsuite/classlibrary/TestUGenMathOptimization.sc b/testsuite/classlibrary/TestUGenMathOptimization.sc
@@ -62,6 +62,11 @@ TestUGenMathOptimization : UnitTest {
 				var bcd = b + c + d;
 				(a + bcd) * (a / bcd);
 			} -> [SinOsc, LFNoise0, DC, Impulse, Sum3, '+', '/', '*', Out],
+			"a + b when a === b should not optimize",
+			{
+				var x = SinOsc.ar([100, 200, 300]).sum();
+				x + x
+			} -> [SinOsc, SinOsc, SinOsc, Sum3, '+', Out],
 		]);
 	}
 
@@ -81,7 +86,12 @@ TestUGenMathOptimization : UnitTest {
 				var ab = a * b;
 				// max is contrived to avoid Sum3 or other optimizations
 				max(ab + c, ab / c)
-			} -> [SinOsc, LFNoise0, '*', DC, '+', '/', 'max', Out]
+			} -> [SinOsc, LFNoise0, '*', DC, '+', '/', 'max', Out],
+			"a + b when a === b should not optimize",
+			{
+				var x = SinOsc.ar(100) * 0.1;
+				x + x
+			} -> [SinOsc, '*', '+', Out],
 		])
 	}
 
@@ -96,7 +106,12 @@ TestUGenMathOptimization : UnitTest {
 				var a = SinOsc.kr(0.1);
 				var b = Rand(0, 1).neg;
 				(a + b) * b
-			} -> [SinOsc, Rand, 'neg', '+', '*', Out]
+			} -> [SinOsc, Rand, 'neg', '+', '*', Out],
+			"a + b when a === b should not optimize",
+			{
+				var x = SinOsc.ar(100).neg;
+				x + x
+			} -> [SinOsc, 'neg', '+', Out],
 		])
 	}
 
@@ -109,7 +124,12 @@ TestUGenMathOptimization : UnitTest {
 				var a = SinOsc.kr(0.1);
 				var b = Rand(0, 1).neg;
 				(a - b) * b
-			} -> [SinOsc, Rand, 'neg', '-', '*', Out]
+			} -> [SinOsc, Rand, 'neg', '-', '*', Out],
+			"a - b when a === b results in a - a",
+			{
+				var x = SinOsc.ar(100).neg;
+				x - x
+			} -> [SinOsc, '-', Out],
 		])
 	}