diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/passes/OptimizeInstructions.cpp | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp index 51a188c15..83bee9a0f 100644 --- a/src/passes/OptimizeInstructions.cpp +++ b/src/passes/OptimizeInstructions.cpp @@ -1965,17 +1965,16 @@ private: curr->left = inner->left; return curr; } - // signed(x - y) <=> 0 => x <=> y + // x - y == 0 => x == y + // x - y != 0 => x != y + // This is not true for signed comparisons like x -y < 0 due to overflow + // effects (e.g. 8 - 0x80000000 < 0 is not the same as 8 < 0x80000000). if (matches(curr, binary(&op, binary(&inner, Abstract::Sub, any(), any()), ival(0))) && (op == Abstract::getBinary(type, Abstract::Eq) || - op == Abstract::getBinary(type, Abstract::Ne) || - op == Abstract::getBinary(type, Abstract::LeS) || - op == Abstract::getBinary(type, Abstract::LtS) || - op == Abstract::getBinary(type, Abstract::GeS) || - op == Abstract::getBinary(type, Abstract::GtS))) { + op == Abstract::getBinary(type, Abstract::Ne))) { curr->right = inner->right; curr->left = inner->left; return curr; |