diff options
| author | Aurelien Jarno <aurelien@aurel32.net> | 2013-09-03 08:27:38 +0200 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2014-02-21 00:34:39 -0600 |
| commit | 6ec62b79e34fb2d3948432df2e7a6bb963c2eae1 (patch) | |
| tree | 1b96f9685985f8d621d52a6dff4d10419f379852 | |
| parent | 0e282aca861e63125ddd2da4fc954ee7421edc8d (diff) | |
| download | qemu-6ec62b79e34fb2d3948432df2e7a6bb963c2eae1.tar.gz | |
tcg/optimize: fix known-zero bits for right shift ops
32-bit versions of sar and shr ops should not propagate known-zero bits
from the unused 32 high bits. For sar it could even lead to wrong code
being generated.
Cc: qemu-stable@nongnu.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
(cherry picked from commit e46b225a3137e62c975c49aaae7bb5f9583cc428)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | tcg/optimize.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/tcg/optimize.c b/tcg/optimize.c index 89e2d6a3b3..c5cdde2160 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -726,16 +726,25 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, mask = temps[args[1]].mask & mask; break; - CASE_OP_32_64(sar): + case INDEX_op_sar_i32: + if (temps[args[2]].state == TCG_TEMP_CONST) { + mask = (int32_t)temps[args[1]].mask >> temps[args[2]].val; + } + break; + case INDEX_op_sar_i64: if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = ((tcg_target_long)temps[args[1]].mask - >> temps[args[2]].val); + mask = (int64_t)temps[args[1]].mask >> temps[args[2]].val; } break; - CASE_OP_32_64(shr): + case INDEX_op_shr_i32: + if (temps[args[2]].state == TCG_TEMP_CONST) { + mask = (uint32_t)temps[args[1]].mask >> temps[args[2]].val; + } + break; + case INDEX_op_shr_i64: if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = temps[args[1]].mask >> temps[args[2]].val; + mask = (uint64_t)temps[args[1]].mask >> temps[args[2]].val; } break; |