scc

Simple C99 Compiler
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commit b5fe10c6fb6606d271bc75e2245a801286f91bb4
parent 0e5ae348472d5ffb37f27761e190c6208554cb9c
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Wed, 18 Mar 2015 07:02:14 +0000

Convert additions to increments

When the immediate value is small is better to use increments instead
of an addition.

Diffstat:
cc2/cgen.c | 11+++++++++++
1 file changed, 11 insertions(+), 0 deletions(-)

diff --git a/cc2/cgen.c b/cc2/cgen.c @@ -243,6 +243,7 @@ static void add(Node *np) { Node *lp = np->left, *rp = np->right; + uint8_t i; if (rp->op == REG || lp->op == CONST) { conmute(np); @@ -300,7 +301,17 @@ add(Node *np) abort(); } add_A: + if (rp->op == CONST) { + if ((i = rp->sym->u.imm) == 0) + goto update_A; + if (i < 4) { + while (i--) + code(INC, lp, NULL); + goto update_A; + } + } code(ADD, lp, rp); + update_A: np->op = REG; np->reg = A; break;