diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/passes/OptimizeInstructions.cpp | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp index dbee3f457..1e51adea9 100644 --- a/src/passes/OptimizeInstructions.cpp +++ b/src/passes/OptimizeInstructions.cpp @@ -537,7 +537,6 @@ struct OptimizeInstructions } } } - // math operations on a constant power of 2 right side can be optimized if (right->type == Type::i32) { BinaryOp op; int32_t c = right->value.geti32(); @@ -550,6 +549,15 @@ struct OptimizeInstructions Bits::getMaxBits(binary->left, this) <= 31) { binary->op = op; } + if (c < 0 && c > std::numeric_limits<int32_t>::min() && + binary->op == DivUInt32) { + // u32(x) / C ==> u32(x) >= C iff C > 2^31 + // We avoid applying this for C == 2^31 due to conflict + // with other rule which transform to more prefereble + // right shift operation. + binary->op = c == -1 ? EqInt32 : GeUInt32; + return binary; + } if (Bits::isPowerOf2((uint32_t)c)) { switch (binary->op) { case MulInt32: @@ -572,6 +580,19 @@ struct OptimizeInstructions Bits::getMaxBits(binary->left, this) <= 63) { binary->op = op; } + if (getPassOptions().shrinkLevel == 0 && c < 0 && + c > std::numeric_limits<int64_t>::min() && + binary->op == DivUInt64) { + // u64(x) / C ==> u64(u64(x) >= C) iff C > 2^63 + // We avoid applying this for C == 2^31 due to conflict + // with other rule which transform to more prefereble + // right shift operation. + // And apply this only for shrinkLevel == 0 due to it + // increasing size by one byte. + binary->op = c == -1LL ? EqInt64 : GeUInt64; + binary->type = Type::i32; + return Builder(*getModule()).makeUnary(ExtendUInt32, binary); + } if (Bits::isPowerOf2((uint64_t)c)) { switch (binary->op) { case MulInt64: @@ -1398,12 +1419,6 @@ private: curr->op = Abstract::getBinary(type, Abstract::Ne); return curr; } - // (unsigned)x / -1 ==> x == -1 - // TODO: i64 as well if sign-extension is enabled - if (matches(curr, binary(DivUInt32, any(), ival(-1)))) { - curr->op = Abstract::getBinary(type, Abstract::Eq); - return curr; - } // x * -1 ==> 0 - x if (matches(curr, binary(Abstract::Mul, any(&left), ival(-1)))) { right->value = Literal::makeZero(type); |