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target/hppa: Optimize UADDCM with no condition

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With r1 as zero is by far the most common usage of UADDCM, as the
easiest way to invert a register.  The compiler does occasionally
use the addition step as well, and we can simplify that to avoid
a temp and write directly into the destination.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2024-03-24 16:26:41 -10:00
parent d0ae87a27c
commit ababac165b
1 changed files with 22 additions and 2 deletions
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24
target/hppa/translate.c
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@ -2763,9 +2763,29 @@ static bool do_uaddcm(DisasContext *ctx, arg_rrr_cf_d *a, bool is_tc)
{
TCGv_i64 tcg_r1, tcg_r2, tmp;
if (a->cf) {
nullify_over(ctx);
if (a->cf == 0) {
tcg_r2 = load_gpr(ctx, a->r2);
tmp = dest_gpr(ctx, a->t);
if (a->r1 == 0) {
/* UADDCM r0,src,dst is the common idiom for dst = ~src. */
tcg_gen_not_i64(tmp, tcg_r2);
} else {
/*
* Recall that r1 - r2 == r1 + ~r2 + 1.
* Thus r1 + ~r2 == r1 - r2 - 1,
* which does not require an extra temporary.
*/
tcg_r1 = load_gpr(ctx, a->r1);
tcg_gen_sub_i64(tmp, tcg_r1, tcg_r2);
tcg_gen_subi_i64(tmp, tmp, 1);
}
save_gpr(ctx, a->t, tmp);
cond_free(&ctx->null_cond);
return true;
}
nullify_over(ctx);
tcg_r1 = load_gpr(ctx, a->r1);
tcg_r2 = load_gpr(ctx, a->r2);
tmp = tcg_temp_new_i64();