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tcg/optimize: Split out fold_ix_to_i 

Pull the "op r, 0, b => movi r, 0" optimization into a function,
and use it in fold_shift.

Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-08-25 20:42:04 -07:00
parent a63ce0e9cb
commit da48e27202
1 changed files with 10 additions and 18 deletions
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28
tcg/optimize.c
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@ -731,6 +731,15 @@ static bool fold_to_not(OptContext *ctx, TCGOp *op, int idx)
return false;
}
/* If the binary operation has first argument @i, fold to @i. */
static bool fold_ix_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (arg_is_const(op->args[1]) && arg_info(op->args[1])->val == i) {
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
}
return false;
}
/* If the binary operation has first argument @i, fold to NOT. */
static bool fold_ix_to_not(OptContext *ctx, TCGOp *op, uint64_t i)
{
@ -1384,6 +1393,7 @@ static bool fold_sextract(OptContext *ctx, TCGOp *op)
static bool fold_shift(OptContext *ctx, TCGOp *op)
{
if (fold_const2(ctx, op) ||
fold_ix_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, 0)) {
return true;
}
@ -1552,24 +1562,6 @@ void tcg_optimize(TCGContext *s)
break;
}
/* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
and "sub r, 0, a => neg r, a" case. */
switch (opc) {
CASE_OP_32_64(shl):
CASE_OP_32_64(shr):
CASE_OP_32_64(sar):
CASE_OP_32_64(rotl):
CASE_OP_32_64(rotr):
if (arg_is_const(op->args[1])
&& arg_info(op->args[1])->val == 0) {
tcg_opt_gen_movi(&ctx, op, op->args[0], 0);
continue;
}
break;
default:
break;
}
/* Simplify using known-zero bits. Currently only ops with a single
output argument is supported. */
z_mask = -1;