tcg/optimize: add optimizations for ext_i32_i64 and extu_i32_i64 ops

They behave the same as ext32s_i64 and ext32u_i64 from the constant
folding and zero propagation point of view, except that they can't
be replaced by a mov, so we don't compute the affected value.

Backports commit 8bcb5c8f34f9215d4f88f388c7ff14c9bd5cecd3 from qemu
This commit is contained in:
Aurelien Jarno 2018-02-10 22:47:05 -05:00 committed by Lioncash
parent f279c93768
commit 4bd3d5005e
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@ -348,9 +348,11 @@ static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
CASE_OP_32_64(ext16u):
return (uint16_t)x;
case INDEX_op_ext_i32_i64:
case INDEX_op_ext32s_i64:
return (int32_t)x;
case INDEX_op_extu_i32_i64:
case INDEX_op_ext32u_i64:
return (uint32_t)x;
@ -849,6 +851,15 @@ void tcg_optimize(TCGContext *s)
mask = temps[args[1]].mask & mask;
break;
case INDEX_op_ext_i32_i64:
if ((temps[args[1]].mask & 0x80000000) != 0) {
break;
}
case INDEX_op_extu_i32_i64:
/* We do not compute affected as it is a size changing op. */
mask = (uint32_t)temps[args[1]].mask;
break;
CASE_OP_32_64(andc):
/* Known-zeros does not imply known-ones. Therefore unless
args[2] is constant, we can't infer anything from it. */
@ -1027,6 +1038,8 @@ void tcg_optimize(TCGContext *s)
CASE_OP_32_64(ext16u):
case INDEX_op_ext32s_i64:
case INDEX_op_ext32u_i64:
case INDEX_op_ext_i32_i64:
case INDEX_op_extu_i32_i64:
if (temp_is_const(s, args[1])) {
tmp = do_constant_folding(s, opc, temps[args[1]].val, 0);
tcg_opt_gen_movi(s, op, args, args[0], tmp);