From d5bb407cc4d159bdcebc7975ec74d7fbfbaa1571 Mon Sep 17 00:00:00 2001
From: Michael Matz <matz@suse.de>
Date: Tue, 13 Aug 2019 03:21:58 +0200
Subject: [PATCH] riscv: Add special cases for const operands
RISC-V supports small immediates for some operations, let's
use them.
---
riscv64-gen.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++---
tccgen.c | 2 +-
2 files changed, 65 insertions(+), 4 deletions(-)
diff --git a/riscv64-gen.c b/riscv64-gen.c
index 488ab25e..5b771b91 100644
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@@ -794,8 +794,70 @@ static void gen_opil(int op, int ll)
{
int a, b, d;
int inv = 0;
- int func3 = 0, func7 = 0;
- /* XXX We could special-case some constant args. */
+ int func3 = 0;
+ ll = ll ? 0 : 8;
+ if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
+ int fc = vtop->c.i;
+ if (fc == vtop->c.i && !(((unsigned)fc + (1 << 11)) >> 12)) {
+ int cll = 0;
+ vswap();
+ gv(RC_INT);
+ a = ireg(vtop[0].r);
+ --vtop;
+ d = get_reg(RC_INT);
+ ++vtop;
+ vswap();
+ switch (op) {
+ case '-':
+ if (fc <= -(1 << 11))
+ break;
+ fc = -fc;
+ case '+':
+ func3 = 0; // addi d, a, fc
+ do_cop:
+ EI(0x13 | cll, func3, ireg(d), a, fc);
+ --vtop;
+ vtop[0].r = d;
+ return;
+ case TOK_LE:
+ if (fc >= (1 << 11) - 1)
+ break;
+ ++fc;
+ case TOK_LT: func3 = 2; goto do_cop; // slti d, a, fc
+ case TOK_ULE:
+ if (fc >= (1 << 11) - 1)
+ break;
+ ++fc;
+ case TOK_ULT: func3 = 3; goto do_cop; // sltiu d, a, fc
+ case '^': func3 = 4; goto do_cop; // xori d, a, fc
+ case '|': func3 = 6; goto do_cop; // ori d, a, fc
+ case '&': func3 = 7; goto do_cop; // andi d, a, fc
+ case TOK_SHL: func3 = 1; fc &= 63; goto do_cop; // slli d, a, fc
+ case TOK_SHR: func3 = 5; cll = ll; fc &= 63; goto do_cop; // srli d, a, fc
+ case TOK_SAR: func3 = 5; cll = ll; fc = 1024 | (fc & 63); goto do_cop;
+
+ case TOK_UGE:
+ case TOK_UGT:
+ case TOK_GE:
+ case TOK_GT:
+ gen_opil(op - 1, ll);
+ EI(0x13, 4, ireg(vtop->r), ireg(vtop->r), 1);// xori d, d, 1
+ return;
+
+ case TOK_NE:
+ case TOK_EQ:
+ if (fc)
+ gen_opil('-', ll), a = ireg(vtop++->r);
+ if (op == TOK_NE)
+ o(0x33 | (3 << 12) | (ireg(d) << 7) | (0 << 15) | (a << 20)); // sltu d, x0, a == snez d,a
+ else
+ EI(0x13, 3, ireg(d), a, 1); // sltiu d, a, 1 == seqz d,a
+ --vtop;
+ vtop[0].r = d;
+ return;
+ }
+ }
+ }
gv2(RC_INT, RC_INT);
a = ireg(vtop[-1].r);
b = ireg(vtop[0].r);
@@ -804,7 +866,6 @@ static void gen_opil(int op, int ll)
vtop++;
vtop[0].r = d;
d = ireg(d);
- ll = ll ? 0 : 8;
switch (op) {
default:
tcc_error("implement me: %s(%s)", __FUNCTION__, get_tok_str(op, NULL));
diff --git a/tccgen.c b/tccgen.c
index 14c7b014..262f42d6 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -2151,7 +2151,7 @@ static void gen_opic(int op)
} else {
/* if commutative ops, put c2 as constant */
if (c1 && (op == '+' || op == '&' || op == '^' ||
- op == '|' || op == '*')) {
+ op == '|' || op == '*' || op == TOK_EQ || op == TOK_NE)) {
vswap();
c2 = c1; //c = c1, c1 = c2, c2 = c;
l2 = l1; //l = l1, l1 = l2, l2 = l;