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| author | Richard Henderson <rth@twiddle.net> | 2014-03-18 07:45:39 -0700 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2014-04-18 16:57:36 -0700 |
| commit | 50c5c4d12557ede48c573e5138542061acd83500 (patch) | |
| tree | 62522d36a81c14cc46b1db93766fc4f118d1dc95 /tcg | |
| parent | 20022fa15f6a8ddc24a8f9d7d177312fecc7fb3a (diff) | |
| download | qemu-50c5c4d12557ede48c573e5138542061acd83500.tar.gz qemu-50c5c4d12557ede48c573e5138542061acd83500.tar.bz2 qemu-50c5c4d12557ede48c573e5138542061acd83500.zip | |
tcg: Mask shift quantities while folding
The TCG result would be undefined, but we can at least produce one
plausible result and avoid triggering the wrath of analysis tools.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'tcg')
| -rw-r--r-- | tcg/optimize.c | 35 |
1 files changed, 20 insertions, 15 deletions
diff --git a/tcg/optimize.c b/tcg/optimize.c index 7777743e88..2fb708ed40 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -220,34 +220,34 @@ static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y) return x ^ y; case INDEX_op_shl_i32: - return (uint32_t)x << (uint32_t)y; + return (uint32_t)x << (y & 31); case INDEX_op_shl_i64: - return (uint64_t)x << (uint64_t)y; + return (uint64_t)x << (y & 63); case INDEX_op_shr_i32: - return (uint32_t)x >> (uint32_t)y; + return (uint32_t)x >> (y & 31); case INDEX_op_shr_i64: - return (uint64_t)x >> (uint64_t)y; + return (uint64_t)x >> (y & 63); case INDEX_op_sar_i32: - return (int32_t)x >> (int32_t)y; + return (int32_t)x >> (y & 31); case INDEX_op_sar_i64: - return (int64_t)x >> (int64_t)y; + return (int64_t)x >> (y & 63); case INDEX_op_rotr_i32: - return ror32(x, y); + return ror32(x, y & 31); case INDEX_op_rotr_i64: - return ror64(x, y); + return ror64(x, y & 63); case INDEX_op_rotl_i32: - return rol32(x, y); + return rol32(x, y & 31); case INDEX_op_rotl_i64: - return rol64(x, y); + return rol64(x, y & 63); CASE_OP_32_64(not): return ~x; @@ -806,29 +806,34 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, case INDEX_op_sar_i32: if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = (int32_t)temps[args[1]].mask >> temps[args[2]].val; + tmp = temps[args[2]].val & 31; + mask = (int32_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_sar_i64: if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = (int64_t)temps[args[1]].mask >> temps[args[2]].val; + tmp = temps[args[2]].val & 63; + mask = (int64_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_shr_i32: if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = (uint32_t)temps[args[1]].mask >> temps[args[2]].val; + tmp = temps[args[2]].val & 31; + mask = (uint32_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_shr_i64: if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = (uint64_t)temps[args[1]].mask >> temps[args[2]].val; + tmp = temps[args[2]].val & 63; + mask = (uint64_t)temps[args[1]].mask >> tmp; } break; CASE_OP_32_64(shl): if (temps[args[2]].state == TCG_TEMP_CONST) { - mask = temps[args[1]].mask << temps[args[2]].val; + tmp = temps[args[2]].val & (TCG_TARGET_REG_BITS - 1); + mask = temps[args[1]].mask << tmp; } break; |