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| author | Max Graey <maxgraey@gmail.com> | 2020-11-11 01:56:14 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-11-10 15:56:14 -0800 |
| commit | bb124f995527f650d98bdac30b00b125b76fab9c (patch) | |
| tree | 05c63599a575cf40b1aff5ed5c4da7211324bb28 | |
| parent | 236296d8563e0f90c3b57f32f1f8f63bac414b89 (diff) | |
| download | binaryen-bb124f995527f650d98bdac30b00b125b76fab9c.tar.gz binaryen-bb124f995527f650d98bdac30b00b125b76fab9c.tar.bz2 binaryen-bb124f995527f650d98bdac30b00b125b76fab9c.zip | |
Optimize i32(x) % C_pot in boolean context (#3307)
bool(i32(x) % C_pot) -> bool(i32(x) & (C_pot - 1))
bool(i32(x) % min_s) -> bool(i32(x) & max_s)
For all other situations we already do this for (i32|i64).rem_s
| -rw-r--r-- | src/passes/OptimizeInstructions.cpp | 19 | ||||
| -rw-r--r-- | test/passes/optimize-instructions_all-features.txt | 20 | ||||
| -rw-r--r-- | test/passes/optimize-instructions_all-features.wast | 18 |
3 files changed, 55 insertions, 2 deletions
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp index 3952c765f..51a188c15 100644 --- a/src/passes/OptimizeInstructions.cpp +++ b/src/passes/OptimizeInstructions.cpp @@ -431,8 +431,8 @@ struct OptimizeInstructions curr->cast<Binary>()->right = y; return curr; } - // i32(x) <<>> (y & 32) ==> x - // i64(x) <<>> (y & 64) ==> x + // i32(x) <<>> (y & C) ==> x, where (C & 31) == 0 + // i64(x) <<>> (y & C) ==> x, where (C & 63) == 0 if (((c->type == Type::i32 && (c->value.geti32() & 31) == 0) || (c->type == Type::i64 && (c->value.geti64() & 63LL) == 0LL)) && !effects(y).hasSideEffects()) { @@ -1052,6 +1052,21 @@ private: // return binary; // } } + } else if (binary->op == RemSInt32) { + // bool(i32(x) % C_pot) ==> bool(x & (C_pot - 1)) + // bool(i32(x) % min_s) ==> bool(x & max_s) + if (auto* c = binary->right->dynCast<Const>()) { + if (c->value.isSignedMin() || + Bits::isPowerOf2(c->value.abs().geti32())) { + binary->op = AndInt32; + if (c->value.isSignedMin()) { + c->value = Literal::makeSignedMax(Type::i32); + } else { + c->value = c->value.abs().sub(Literal::makeOne(Type::i32)); + } + return binary; + } + } } if (auto* ext = Properties::getSignExtValue(binary)) { // use a cheaper zero-extent, we just care about the boolean value diff --git a/test/passes/optimize-instructions_all-features.txt b/test/passes/optimize-instructions_all-features.txt index a5cc470fb..88b053835 100644 --- a/test/passes/optimize-instructions_all-features.txt +++ b/test/passes/optimize-instructions_all-features.txt @@ -4005,6 +4005,26 @@ (i32.const 0) ) ) + (drop + (if (result i32) + (i32.and + (local.get $x) + (i32.const 3) + ) + (i32.const 1) + (i32.const 0) + ) + ) + (drop + (if (result i32) + (i32.and + (local.get $x) + (i32.const 2147483647) + ) + (i32.const 1) + (i32.const 0) + ) + ) ) (func $optimize-bitwise-oprations (param $x i32) (param $y i32) (param $z i64) (param $w i64) (drop diff --git a/test/passes/optimize-instructions_all-features.wast b/test/passes/optimize-instructions_all-features.wast index b28536519..5804c1b2a 100644 --- a/test/passes/optimize-instructions_all-features.wast +++ b/test/passes/optimize-instructions_all-features.wast @@ -4517,6 +4517,24 @@ ) (i32.const 0) )) + ;; (signed)x % 4 ? 1 : 0 + (drop (if (result i32) + (i32.rem_s + (local.get $x) + (i32.const 4) + ) + (i32.const 1) + (i32.const 0) + )) + ;; (signed)x % min_s ? 1 : 0 + (drop (if (result i32) + (i32.rem_s + (local.get $x) + (i32.const 0x80000000) + ) + (i32.const 1) + (i32.const 0) + )) ) (func $optimize-bitwise-oprations (param $x i32) (param $y i32) (param $z i64) (param $w i64) ;; ~(1 << x) -> rotl(-2, x) |