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Catch NaN explicitly in expand_fcvt_to_uint().

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When the input is a NaN, we need to generate a different trap code, so
use the new trapff instruction to generate such a trap after the first
floating point comparison.
This commit is contained in:
Jakob Stoklund Olesen
2018-02-20 14:44:57 -08:00
parent b9b1d0fcd5
commit c846ec1626
1 changed files with 30 additions and 8 deletions
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38
lib/cretonne/src/isa/intel/enc_tables.rs
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@@ -449,21 +449,43 @@ fn expand_fcvt_to_uint(
ir::types::F64 => pos.ins().f64const(Ieee64::pow2(ty.lane_bits() - 1)),
_ => panic!("Can't convert {}", xty),
};
let is_large = pos.ins().fcmp(FloatCC::GreaterThanOrEqual, x, pow2nm1);
pos.ins().brnz(is_large, large, &[]);
let is_large = pos.ins().ffcmp(x, pow2nm1);
pos.ins().brff(
FloatCC::GreaterThanOrEqual,
is_large,
large,
&[],
);
// Now we know that x < 2^(N-1) or x is NaN.
// We need to generate a specific trap code when `x` is NaN, so reuse the flags from the
// previous comparison.
pos.ins().trapff(
FloatCC::Unordered,
is_large,
ir::TrapCode::BadConversionToInteger,
);
// Now we know that x < 2^(N-1) and not NaN.
let sres = pos.ins().x86_cvtt2si(ty, x);
let is_neg = pos.ins().icmp_imm(IntCC::SignedLessThan, sres, 0);
pos.ins().brz(is_neg, done, &[sres]);
pos.ins().trap(ir::TrapCode::BadConversionToInteger);
let is_neg = pos.ins().ifcmp_imm(sres, 0);
pos.ins().brif(
IntCC::SignedGreaterThanOrEqual,
is_neg,
done,
&[sres],
);
pos.ins().trap(ir::TrapCode::IntegerOverflow);
// Handle the case where x >= 2^(N-1) and not NaN.
pos.insert_ebb(large);
let adjx = pos.ins().fsub(x, pow2nm1);
let lres = pos.ins().x86_cvtt2si(ty, adjx);
let is_neg = pos.ins().icmp_imm(IntCC::SignedLessThan, lres, 0);
pos.ins().trapnz(is_neg, ir::TrapCode::IntegerOverflow);
let is_neg = pos.ins().ifcmp_imm(lres, 0);
pos.ins().trapif(
IntCC::SignedLessThan,
is_neg,
ir::TrapCode::IntegerOverflow,
);
let lfinal = pos.ins().iadd_imm(lres, 1 << (ty.lane_bits() - 1));
// Recycle the original instruction as a jump.