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| author | isharipo <iskander.sharipov@intel.com> | 2017-11-20 20:56:05 +0300 |
|---|---|---|
| committer | Ilya Tocar <ilya.tocar@intel.com> | 2017-11-21 20:29:59 +0000 |
| commit | 49322ca9ede175cbd62de601ddc1170edcaae1a7 (patch) | |
| tree | 1932737f4ed66c5d33c5990baca5353e521af9d3 /src/cmd/asm | |
| parent | 78615844f536c6664909e3269652f4938fd2b027 (diff) | |
| download | go-49322ca9ede175cbd62de601ddc1170edcaae1a7.tar.xz | |
cmd/internal/obj/x86: fix /is4 encoding for VBLEND
Fixes VBLENDVP{D/S}, VPBLENDVB encoding for /is4 imm8[7:4]
encoded register operand.
Explanation:
`reg[r]+regrex[r]+1` will yield correct values for 8..15 reg indexes,
but for 0..7 it gives `index+1` results.
There was no test that used lower 8 register with /is4 encoding,
so the bug passed the tests.
The proper solution is to get 4th bit from regrex with a proper shift:
`reg[r]|(regrex[r]<<1)`.
Instead of inlining `reg[r]|(regrex[r]<<1)` expr,
using new `regIndex(r)` function.
Test that reproduces this issue is added to
amd64enc_extra.s test suite.
Bug came from https://golang.org/cl/70650.
Change-Id: I846a25e88d5e6df88df9d9c3f5fe94ec55416a33
Reviewed-on: https://go-review.googlesource.com/78815
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
Diffstat (limited to 'src/cmd/asm')
| -rw-r--r-- | src/cmd/asm/internal/asm/testdata/amd64enc_extra.s | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s b/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s index 6b4d7c7356..a5bcb0f9bc 100644 --- a/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s +++ b/src/cmd/asm/internal/asm/testdata/amd64enc_extra.s @@ -233,5 +233,7 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$0 VPGATHERQQ Y0, (R13)(Y1*1), Y2 // c4c2fd91540d00 VPGATHERQQ Y0, 16(R13)(Y1*1), Y2 // c4c2fd91540d10 VPGATHERQQ Y0, 512(R13)(Y1*1), Y2 // c4c2fd91940d00020000 + // Test low-8 register for /is4 "hr" operand. + VPBLENDVB X0, (BX), X1, X2 // c4e3714c1300 // End of tests. RET |