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| author | Richard Henderson | 2020-03-11 06:14:26 +0100 |
|---|---|---|
| committer | Richard Henderson | 2020-03-17 16:41:07 +0100 |
| commit | 312b426fea4d6dd322d7472c80010a8ba7a166d2 (patch) | |
| tree | 638325efa9778bcff81cf578f671bdc9690a6bc9 /tcg | |
| parent | Merge remote-tracking branch 'remotes/kraxel/tags/usb-20200317-pull-request' ... (diff) | |
| download | qemu-312b426fea4d6dd322d7472c80010a8ba7a166d2.tar.gz qemu-312b426fea4d6dd322d7472c80010a8ba7a166d2.tar.xz qemu-312b426fea4d6dd322d7472c80010a8ba7a166d2.zip | |
tcg/i386: Bound shift count expanding sari_vec
A given RISU testcase for SVE can produce
tcg-op-vec.c:511: do_shifti: Assertion `i >= 0 && i < (8 << vece)' failed.
because expand_vec_sari gave a shift count of 32 to a MO_32
vector shift.
In 44f1441dbe1, we changed from direct expansion of vector opcodes
to re-use of the tcg expanders. So while the comment correctly notes
that the hw will handle such a shift count, we now have to take our
own sanity checks into account. Which is easy in this particular case.
Fixes: 44f1441dbe1
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg')
| -rw-r--r-- | tcg/i386/tcg-target.inc.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index cdedcb2b25..223dba9c8c 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -3391,12 +3391,15 @@ static void expand_vec_sari(TCGType type, unsigned vece, case MO_64: if (imm <= 32) { - /* We can emulate a small sign extend by performing an arithmetic + /* + * We can emulate a small sign extend by performing an arithmetic * 32-bit shift and overwriting the high half of a 64-bit logical - * shift (note that the ISA says shift of 32 is valid). + * shift. Note that the ISA says shift of 32 is valid, but TCG + * does not, so we have to bound the smaller shift -- we get the + * same result in the high half either way. */ t1 = tcg_temp_new_vec(type); - tcg_gen_sari_vec(MO_32, t1, v1, imm); + tcg_gen_sari_vec(MO_32, t1, v1, MIN(imm, 31)); tcg_gen_shri_vec(MO_64, v0, v1, imm); vec_gen_4(INDEX_op_x86_blend_vec, type, MO_32, tcgv_vec_arg(v0), tcgv_vec_arg(v0), |