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Fix legalization of icmp ugt (#1278)

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Previously, the same pattern (pmax + pcmpeq) as `uge` was used but this logic was incorrect for operands with equal values.
This commit is contained in:
Andrew Brown
2019-12-16 13:14:51 -08:00
committed by Sean Stangl
parent 6181f20326
commit 4433ad2858
3 changed files with 25 additions and 5 deletions
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12
cranelift/codegen/meta/src/isa/x86/legalize.rs
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@@ -335,6 +335,7 @@ pub(crate) fn define(shared: &mut SharedDefinitions, x86_instructions: &Instruct
let uimm8_zero = Literal::constant(&imm.uimm8, 0x00);
let uimm8_one = Literal::constant(&imm.uimm8, 0x01);
let u128_zeroes = constant(vec![0x00; 16]);
let u128_ones = constant(vec![0xff; 16]);
let b = var("b");
let c = var("c");
let d = var("d");
@@ -405,12 +406,11 @@ pub(crate) fn define(shared: &mut SharedDefinitions, x86_instructions: &Instruct
}
// SIMD bnot
let ones = constant(vec![0xff; 16]);
for ty in ValueType::all_lane_types().filter(allowed_simd_type) {
let bnot = bnot.bind(vector(ty, sse_vector_size));
narrow.legalize(
def!(y = bnot(x)),
vec![def!(a = vconst(ones)), def!(y = bxor(a, x))],
vec![def!(a = vconst(u128_ones)), def!(y = bxor(a, x))],
);
}
@@ -524,7 +524,11 @@ pub(crate) fn define(shared: &mut SharedDefinitions, x86_instructions: &Instruct
let icmp_ = icmp.bind(vector(*ty, sse_vector_size));
narrow.legalize(
def!(c = icmp_(ugt, a, b)),
vec![def!(x = x86_pmaxu(a, b)), def!(c = icmp(eq, a, x))],
vec![
def!(x = x86_pmaxu(a, b)),
def!(y = icmp(eq, x, b)),
def!(c = bnot(y)),
],
);
let icmp_ = icmp.bind(vector(*ty, sse_vector_size));
narrow.legalize(
@@ -574,7 +578,7 @@ pub(crate) fn define(shared: &mut SharedDefinitions, x86_instructions: &Instruct
narrow.legalize(
def!(b = fabs(a)),
vec![
def!(c = vconst(ones)),
def!(c = vconst(u128_ones)),
def!(d = ushr_imm(c, uimm8_one)), // Create a mask of all 1s except the MSB.
def!(e = bitcast_to_float(d)), // Cast mask to the floating-point type.
def!(b = band(a, e)), // Unset the MSB.