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Simplify jump table instructions and add missing conversion;

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This makes non-legalized jump table instructions operate on operands with
pointer-sized types. This means we need to extend smaller types into the
pointer-sized operand, when the two don't match.
This commit is contained in:
Benjamin Bouvier
2019-08-01 17:05:38 +02:00
parent f0d7438728
commit 627ba24b59
5 changed files with 27 additions and 27 deletions
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21
cranelift/codegen/meta/src/shared/instructions.rs
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@@ -269,15 +269,9 @@ pub fn define(
.is_branch(true),
);
// The index into the br_table can be any type; legalizer will convert it to the right type.
let x = &operand_doc("x", iB, "index into jump table");
let Entry = &TypeVar::new(
"Entry",
"A scalar integer type",
TypeSetBuilder::new().ints(Interval::All).build(),
);
let entry = &operand_doc("entry", Entry, "entry of jump table");
let entry = &operand_doc("entry", iAddr, "entry of jump table");
let JT = &operand("JT", jump_table);
ig.push(
@@ -305,6 +299,9 @@ pub fn define(
.is_branch(true),
);
// These are the instructions which br_table legalizes to: they perform address computations,
// using pointer-sized integers, so their type variables are more constrained.
let x = &operand_doc("x", iAddr, "index into jump table");
let Size = &operand_doc("Size", uimm8, "Size in bytes");
ig.push(
@@ -2644,11 +2641,11 @@ pub fn define(
Cast the bits in `x` as a different type of the same bit width.
This instruction does not change the data's representation but allows
data in registers to be used as different types, e.g. an i32x4 as a
b8x16. The only constraint on the result `a` is that it can be
data in registers to be used as different types, e.g. an i32x4 as a
b8x16. The only constraint on the result `a` is that it can be
`raw_bitcast` back to the original type. Also, in a raw_bitcast between
vector types with the same number of lanes, the value of each result
lane is a raw_bitcast of the corresponding operand lane. TODO there is
vector types with the same number of lanes, the value of each result
lane is a raw_bitcast of the corresponding operand lane. TODO there is
currently no mechanism for enforcing the bit width constraint.
"#,
)