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Fix/128 bit ints operations #349

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Merged
merged 2 commits into from
Oct 8, 2023
Merged

Fix/128 bit ints operations #349

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b3fecae
Fix 128-bit non-native integers comparison
antoyo Oct 7, 2023
b3c10d4
Fix 128-bit non-native integers negation
antoyo Oct 7, 2023
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2 changes: 2 additions & 0 deletions Readme.md
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Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,8 @@ $ LIBRARY_PATH=$(cat gcc_path) LD_LIBRARY_PATH=$(cat gcc_path) rustc +$(cat $CG_
<dd>Display the time it took to perform codegen for a crate</dd>
<dt>CG_RUSTFLAGS</dt>
<dd>Send additional flags to rustc. Can be used to build the sysroot without unwinding by setting `CG_RUSTFLAGS=-Cpanic=abort`.</dd>
<dt>CG_GCCJIT_DUMP_TO_FILE</dt>
<dd>Dump a C-like representation to /tmp/gccjit_dumps and enable debug info in order to debug this C-like representation.</dd>
</dl>

## Licensing
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73 changes: 55 additions & 18 deletions src/int.rs
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Expand Up @@ -36,7 +36,6 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
self.cx.context.new_unary_op(None, operation, typ, a)
}
else {
// TODO(antoyo): use __negdi2 and __negti2 instead?
let element_type = typ.dyncast_array().expect("element type");
let values = [
self.cx.context.new_unary_op(None, UnaryOp::BitwiseNegate, element_type, self.low(a)),
Expand All @@ -52,9 +51,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
self.cx.context.new_unary_op(None, UnaryOp::Minus, a.get_type(), a)
}
else {
let param_a = self.context.new_parameter(None, a_type, "a");
let func = self.context.new_function(None, FunctionType::Extern, a_type, &[param_a], "__negti2", false);
self.context.new_call(None, func, &[a])
self.gcc_add(self.gcc_not(a), self.gcc_int(a_type, 1))
}
}

Expand Down Expand Up @@ -353,23 +350,63 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
(res.dereference(None).to_rvalue(), overflow)
}

pub fn gcc_icmp(&self, op: IntPredicate, mut lhs: RValue<'gcc>, mut rhs: RValue<'gcc>) -> RValue<'gcc> {
pub fn gcc_icmp(&mut self, op: IntPredicate, mut lhs: RValue<'gcc>, mut rhs: RValue<'gcc>) -> RValue<'gcc> {
let a_type = lhs.get_type();
let b_type = rhs.get_type();
if self.is_non_native_int_type(a_type) || self.is_non_native_int_type(b_type) {
let signed = a_type.is_compatible_with(self.i128_type);
let sign =
if signed {
""
}
else {
"u"
};
let func_name = format!("__{}cmpti2", sign);
let param_a = self.context.new_parameter(None, a_type, "a");
let param_b = self.context.new_parameter(None, b_type, "b");
let func = self.context.new_function(None, FunctionType::Extern, self.int_type, &[param_a, param_b], func_name, false);
let cmp = self.context.new_call(None, func, &[lhs, rhs]);
// This algorithm is based on compiler-rt's __cmpti2:
// https://github.com/llvm-mirror/compiler-rt/blob/f0745e8476f069296a7c71accedd061dce4cdf79/lib/builtins/cmpti2.c#L21
let result = self.current_func().new_local(None, self.int_type, "icmp_result");
let block1 = self.current_func().new_block("block1");
let block2 = self.current_func().new_block("block2");
let block3 = self.current_func().new_block("block3");
let block4 = self.current_func().new_block("block4");
let block5 = self.current_func().new_block("block5");
let block6 = self.current_func().new_block("block6");
let block7 = self.current_func().new_block("block7");
let block8 = self.current_func().new_block("block8");
let after = self.current_func().new_block("after");

let native_int_type = a_type.dyncast_array().expect("get element type");
// NOTE: cast low to its unsigned type in order to perform a comparison correctly (e.g.
// the sign is only on high).
let unsigned_type = native_int_type.to_unsigned(&self.cx);

let lhs_low = self.context.new_cast(None, self.low(lhs), unsigned_type);
let rhs_low = self.context.new_cast(None, self.low(rhs), unsigned_type);

let condition = self.context.new_comparison(None, ComparisonOp::LessThan, self.high(lhs), self.high(rhs));
self.llbb().end_with_conditional(None, condition, block1, block2);

block1.add_assignment(None, result, self.context.new_rvalue_zero(self.int_type));
block1.end_with_jump(None, after);

let condition = self.context.new_comparison(None, ComparisonOp::GreaterThan, self.high(lhs), self.high(rhs));
block2.end_with_conditional(None, condition, block3, block4);

block3.add_assignment(None, result, self.context.new_rvalue_from_int(self.int_type, 2));
block3.end_with_jump(None, after);

let condition = self.context.new_comparison(None, ComparisonOp::LessThan, lhs_low, rhs_low);
block4.end_with_conditional(None, condition, block5, block6);

block5.add_assignment(None, result, self.context.new_rvalue_zero(self.int_type));
block5.end_with_jump(None, after);

let condition = self.context.new_comparison(None, ComparisonOp::GreaterThan, lhs_low, rhs_low);
block6.end_with_conditional(None, condition, block7, block8);

block7.add_assignment(None, result, self.context.new_rvalue_from_int(self.int_type, 2));
block7.end_with_jump(None, after);

block8.add_assignment(None, result, self.context.new_rvalue_one(self.int_type));
block8.end_with_jump(None, after);

// NOTE: since jumps were added in a place rustc does not expect, the current block in the
// state need to be updated.
self.switch_to_block(after);

let cmp = result.to_rvalue();
let (op, limit) =
match op {
IntPredicate::IntEQ => {
Expand Down