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Merge pull request from GHSA-xm67-587q-r2vw

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This commit fixes an off-by-one error in the subtraction of indices when
shuffling a vector with itself. Lanes 16-and-above are mapped to select
from the first vector since the first and second element are the same,
but the subtraction was with 15 rather than 16 by accident.
This commit is contained in:
Alex Crichton
2023-03-08 13:00:00 -06:00
committed by GitHub
parent e8331661cb
commit 5dc2bbccbb
3 changed files with 10 additions and 2 deletions
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2
cranelift/codegen/src/isa/x64/lower/isle.rs
View File

@@ -752,7 +752,7 @@ impl Context for IsleContext<'_, '_, MInst, X64Backend> {
fn shuffle_0_31_mask(&mut self, mask: &VecMask) -> VCodeConstant {
let mask = mask
.iter()
.map(|&b| if b > 15 { b.wrapping_sub(15) } else { b })
.map(|&b| if b > 15 { b.wrapping_sub(16) } else { b })
.map(|b| if b > 15 { 0b10000000 } else { b })
.collect();
self.lower_ctx

3
cranelift/filetests/filetests/isa/x64/simd-lane-access-compile.clif
View File

@@ -101,7 +101,8 @@ block0:
; addb %al, (%rax)
; addb %al, (%rax)
; addb %al, (%rax)
; addb %al, (%rcx, %rax)
; addb %al, (%rbx)
; addl %eax, (%rax)
; addb %al, (%rax)
; addb %al, (%rax)
; addb %al, (%rax)

7
cranelift/filetests/filetests/runtests/simd-shuffle.clif
View File

@@ -19,3 +19,10 @@ block0(v0: i8x16, v1: i8x16):
return v2
}
; run: %shuffle_zeros([1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16], [17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32]) == [4 1 0 0 5 7 13 12 24 14 25 5 3 0 18 6]
function %shuffle1(i8x16) -> i8x16 {
block0(v0: i8x16):
v1 = shuffle v0, v0, [8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23]
return v1
}
; run: %shuffle1([0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15]) == [8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7]