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tcg/optimize: Propagate sign info for logical operations 

Sign repetitions are perforce all identical, whether they are 1 or 0.
Bitwise operations preserve the relative quantity of the repetitions.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
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>
staging
Richard Henderson 2021-08-26 13:08:54 -07:00
parent 57fe5c6df2
commit 3f2b1f8376
1 changed files with 29 additions and 0 deletions
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29
tcg/optimize.c
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@ -967,6 +967,13 @@ static bool fold_and(OptContext *ctx, TCGOp *op)
z2 = arg_info(op->args[2])->z_mask;
ctx->z_mask = z1 & z2;
/*
* Sign repetitions are perforce all identical, whether they are 1 or 0.
* Bitwise operations preserve the relative quantity of the repetitions.
*/
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
/*
* Known-zeros does not imply known-ones. Therefore unless
* arg2 is constant, we can't infer affected bits from it.
@ -1002,6 +1009,8 @@ static bool fold_andc(OptContext *ctx, TCGOp *op)
}
ctx->z_mask = z1;
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return fold_masks(ctx, op);
}
@ -1300,6 +1309,9 @@ static bool fold_eqv(OptContext *ctx, TCGOp *op)
fold_xi_to_not(ctx, op, 0)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
@ -1487,6 +1499,8 @@ static bool fold_movcond(OptContext *ctx, TCGOp *op)
ctx->z_mask = arg_info(op->args[3])->z_mask
| arg_info(op->args[4])->z_mask;
ctx->s_mask = arg_info(op->args[3])->s_mask
& arg_info(op->args[4])->s_mask;
if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
uint64_t tv = arg_info(op->args[3])->val;
@ -1585,6 +1599,9 @@ static bool fold_nand(OptContext *ctx, TCGOp *op)
fold_xi_to_not(ctx, op, -1)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
@ -1614,6 +1631,9 @@ static bool fold_nor(OptContext *ctx, TCGOp *op)
fold_xi_to_not(ctx, op, 0)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
@ -1623,6 +1643,8 @@ static bool fold_not(OptContext *ctx, TCGOp *op)
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask;
/* Because of fold_to_not, we want to always return true, via finish. */
finish_folding(ctx, op);
return true;
@ -1638,6 +1660,8 @@ static bool fold_or(OptContext *ctx, TCGOp *op)
ctx->z_mask = arg_info(op->args[1])->z_mask
| arg_info(op->args[2])->z_mask;
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return fold_masks(ctx, op);
}
@ -1649,6 +1673,9 @@ static bool fold_orc(OptContext *ctx, TCGOp *op)
fold_ix_to_not(ctx, op, 0)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
@ -1922,6 +1949,8 @@ static bool fold_xor(OptContext *ctx, TCGOp *op)
ctx->z_mask = arg_info(op->args[1])->z_mask
| arg_info(op->args[2])->z_mask;
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return fold_masks(ctx, op);
}