skia2/resources/sksl/folding/ShortCircuitBoolFolding.sksl
John Stiles 639e812d9f Remove usage of sqrt() as an optimization barrier in tests.
In the majority of cases, a uniform is an equally good substitute, and
replacing `sqrt(N)` with `unknownInput` actually makes the test clearer.

Change-Id: I7bcb477571972d7aa2ce8c49b3674471f7310748
Bug: skia:12034
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/411306
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
2021-05-24 17:18:54 +00:00

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uniform half4 colorRed, colorGreen;
uniform half unknownInput;
bool test() {
bool expr = unknownInput > 0;
int ok = 0, bad = 0;
// Test boolean short-circuiting with constants on the left side.
if (true && expr) { ++ok; } else { ++bad; } // -> (expr)
if (false && expr) { ++bad; } else { ++ok; } // -> (false) -> block removed
if (true ^^ expr) { ++bad; } else { ++ok; } // -> unchanged
if (false ^^ expr) { ++ok; } else { ++bad; } // -> (expr)
if (true || expr) { ++ok; } else { ++bad; } // -> (true)
if (false || expr) { ++ok; } else { ++bad; } // -> (expr)
if (true == expr) { ++ok; } else { ++bad; } // -> (expr)
if (false == expr) { ++bad; } else { ++ok; } // -> unchanged
if (true != expr) { ++bad; } else { ++ok; } // -> unchanged
if (false != expr) { ++ok; } else { ++bad; } // -> (expr)
// Test boolean short-circuiting with constants on the right side.
if (expr && true ) { ++ok; } else { ++bad; } // -> (expr)
if (expr && false) { ++bad; } else { ++ok; } // -> (false) -> block removed
if (expr ^^ true ) { ++bad; } else { ++ok; } // -> unchanged
if (expr ^^ false) { ++ok; } else { ++bad; } // -> (expr)
if (expr || true ) { ++ok; } else { ++bad; } // -> (true)
if (expr || false) { ++ok; } else { ++bad; } // -> (expr)
if (expr == true ) { ++ok; } else { ++bad; } // -> (expr)
if (expr == false) { ++bad; } else { ++ok; } // -> unchanged
if (expr != true ) { ++bad; } else { ++ok; } // -> unchanged
if (expr != false) { ++ok; } else { ++bad; } // -> (expr)
// Test that side-effects in the left-side expression prevent right-side expr elimination.
float a = unknownInput + 2, b = unknownInput * 2;
true || bool(a = b); // -> true
if (a == b) { ++bad; } else { ++ok; }
bool(a = b) || true; // -> unchanged
if (a == b) { ++ok; } else { ++bad; }
return ok == 22 && bad == 0;
}
half4 main(float2 coords) {
return test() ? colorGreen : colorRed;
}