scc

Simple C99 Compiler
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commit afc55f2a912d03aab2cfde5de3ba76de6ece8ac3
parent 42a80b685648b7cb5c417c00b7cc338dcbefc394
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Thu, 12 Feb 2015 12:35:24 +0100

Add optimize function() to cc2

This function runs all the possible optimizations that can be applied.
At this moment only reduction of casting can be used.

Diffstat:
cc2/Makefile | 2+-
cc2/cc2.h | 1+
cc2/main.c | 1+
cc2/optm.c | 43+++++++++++++++++++++++++++++++++++++++++++
4 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/cc2/Makefile b/cc2/Makefile @@ -1,5 +1,5 @@ -OBJS = main.o parser.o cgen.o code.o +OBJS = main.o parser.o cgen.o code.o optm.o CPPFLAGS = -I../inc LDFLAGS = -L../lib diff --git a/cc2/cc2.h b/cc2/cc2.h @@ -117,4 +117,5 @@ extern void genstack(Symbol *fun); extern void apply(Node *list[], Node *(*fun)(Node *)); extern Symbol *parse(void); extern void code(char op, ...); +extern Node *optimize(Node *np); extern void prtree(Node *np); diff --git a/cc2/main.c b/cc2/main.c @@ -31,6 +31,7 @@ main(void) Symbol *fun; while (!feof(stdin) && (fun = parse())) { + apply(fun->u.f.body, optimize); apply(fun->u.f.body, genaddable); generate(fun); } diff --git a/cc2/optm.c b/cc2/optm.c @@ -0,0 +1,43 @@ + +#include <stddef.h> +#include <stdint.h> + +#include <cc.h> +#include "cc2.h" + + +#include <stdio.h> + +static Node * +optcasts(Node *np, Type *tp) +{ + if (!np) + return NULL; + +repeat: + switch (np->op) { + case OCAST: + /* TODO: be careful with the sign */ + if (np->type->c_int && np->type->size >= tp->size) { + np = np->left; + goto repeat; + } + break; + case OASSIG: + tp = np->type; + break; + default: + np->type = tp; + } + + np->left = optcasts(np->left, tp); + np->right = optcasts(np->right, tp); + return np; +} + +Node * +optimize(Node *np) +{ + np = optcasts(np, np->type); + return np; +}