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x64: Mask shift amounts for small types (#4752)

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* x64: Mask shift amounts for small types

* cranelift: Disable i128 shifts in fuzzer again

They are fixed. But we had a bunch of fuzzgen issues come in, and we don't want to accidentaly mark them as fixed

* cranelift: Avoid masking shifts for 32 and 64 bit cases

* cranelift: Add const shift tests and fix them

* cranelift: Remove const `rotl` cases

Now that `put_masked_in_imm8_gpr` works properly we can simplify rotl/rotr
This commit is contained in:
Afonso Bordado
2022-08-24 18:31:38 +01:00
committed by GitHub
parent 9cb987c678
commit d394edcefe
10 changed files with 1920 additions and 117 deletions
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7
cranelift/codegen/src/isa/x64/inst.isle
View File

@@ -1057,7 +1057,12 @@
;;
;; This is used when lowering various shifts and rotates.
(decl put_masked_in_imm8_gpr (Value Type) Imm8Gpr)
(extern constructor put_masked_in_imm8_gpr put_masked_in_imm8_gpr)
(rule (put_masked_in_imm8_gpr (u64_from_iconst amt) ty)
(const_to_type_masked_imm8 amt ty))
(rule (put_masked_in_imm8_gpr amt (fits_in_16 ty))
(x64_and $I64 (value_regs_get_gpr amt 0) (RegMemImm.Imm (shift_mask ty))))
(rule (put_masked_in_imm8_gpr amt ty)
(value_regs_get_gpr amt 0))
;; Condition codes
(type CC extern

10
cranelift/codegen/src/isa/x64/lower.isle
View File

@@ -793,11 +793,6 @@
(rule (lower (has_type (fits_in_64 ty) (rotl src amt)))
(x64_rotl ty src (put_masked_in_imm8_gpr amt ty)))
(rule (lower (has_type (fits_in_64 ty)
(rotl src (u64_from_iconst amt))))
(x64_rotl ty src
(const_to_type_masked_imm8 amt ty)))
;; `i128`.
@@ -819,11 +814,6 @@
(rule (lower (has_type (fits_in_64 ty) (rotr src amt)))
(x64_rotr ty src (put_masked_in_imm8_gpr amt ty)))
(rule (lower (has_type (fits_in_64 ty)
(rotr src (u64_from_iconst amt))))
(x64_rotr ty src
(const_to_type_masked_imm8 amt ty)))
;; `i128`.

21
cranelift/codegen/src/isa/x64/lower/isle.rs
View File

@@ -154,23 +154,6 @@ impl Context for IsleContext<'_, '_, MInst, Flags, IsaFlags, 6> {
RegMem::reg(self.put_in_reg(val))
}
fn put_masked_in_imm8_gpr(&mut self, val: Value, ty: Type) -> Imm8Gpr {
let inputs = self.lower_ctx.get_value_as_source_or_const(val);
if let Some(c) = inputs.constant {
let mask = 1_u64.checked_shl(ty.bits()).map_or(u64::MAX, |x| x - 1);
return Imm8Gpr::new(Imm8Reg::Imm8 {
imm: (c & mask) as u8,
})
.unwrap();
}
Imm8Gpr::new(Imm8Reg::Reg {
reg: self.put_in_regs(val).regs()[0],
})
.unwrap()
}
#[inline]
fn encode_fcmp_imm(&mut self, imm: &FcmpImm) -> u8 {
imm.encode()
@@ -272,7 +255,7 @@ impl Context for IsleContext<'_, '_, MInst, Flags, IsaFlags, 6> {
#[inline]
fn const_to_type_masked_imm8(&mut self, c: u64, ty: Type) -> Imm8Gpr {
let mask = 1_u64.checked_shl(ty.bits()).map_or(u64::MAX, |x| x - 1);
let mask = self.shift_mask(ty) as u64;
Imm8Gpr::new(Imm8Reg::Imm8 {
imm: (c & mask) as u8,
})
@@ -281,6 +264,8 @@ impl Context for IsleContext<'_, '_, MInst, Flags, IsaFlags, 6> {
#[inline]
fn shift_mask(&mut self, ty: Type) -> u32 {
debug_assert!(ty.lane_bits().is_power_of_two());
ty.lane_bits() - 1
}