From e883a152318d2d906660f573314d6d09de88f048 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Sun, 4 Mar 2018 23:55:52 -0500 Subject: [PATCH] target/i386: fix pmovsx/pmovzx in-place operations The SSE4.1 pmovsx* and pmovzx* instructions take packed 1-byte, 2-byte or 4-byte inputs and sign-extend or zero-extend them to a wider vector output. The associated helpers for these instructions do the extension on each element in turn, starting with the lowest. If the input and output are the same register, this means that all the input elements after the first have been overwritten before they are read. This patch makes the helpers extend starting with the highest element, not the lowest, to avoid such overwriting. This fixes many GCC test failures (161 in the gcc testsuite in my GCC 6-based testing) when testing with a default CPU setting enabling those instructions. Backports commit c6a56c8e990b213a1638af2d34352771d5fa4d9c from qemu --- qemu/target/i386/ops_sse.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/qemu/target/i386/ops_sse.h b/qemu/target/i386/ops_sse.h index f4be0296..5bdd9164 100644 --- a/qemu/target/i386/ops_sse.h +++ b/qemu/target/i386/ops_sse.h @@ -1617,18 +1617,18 @@ void glue(helper_ptest, SUFFIX)(CPUX86State *env, Reg *d, Reg *s) #define SSE_HELPER_F(name, elem, num, F) \ void glue(name, SUFFIX)(CPUX86State *env, Reg *d, Reg *s) \ { \ - d->elem(0) = F(0); \ - d->elem(1) = F(1); \ if (num > 2) { \ - d->elem(2) = F(2); \ - d->elem(3) = F(3); \ if (num > 4) { \ - d->elem(4) = F(4); \ - d->elem(5) = F(5); \ - d->elem(6) = F(6); \ d->elem(7) = F(7); \ + d->elem(6) = F(6); \ + d->elem(5) = F(5); \ + d->elem(4) = F(4); \ } \ + d->elem(3) = F(3); \ + d->elem(2) = F(2); \ } \ + d->elem(1) = F(1); \ + d->elem(0) = F(0); \ } SSE_HELPER_F(helper_pmovsxbw, W, 8, (int8_t) s->B)