4 files changed, 15 insertions, 2 deletions
diff --git a/common.h b/common.h
index 81c24ad..53669f4 100644
--- a/common.h
+++ b/common.h
@@ -132,6 +132,10 @@ struct option {
    bool nocolor;
    bool pie, pic;
    bool werror;
+   enum optz {
+      OPT0 = -1,
+      OPT1 = 1,
+   } o;
    union {
       struct {
          bool p : 1, /* after parsing */
diff --git a/ir/ir.c b/ir/ir.c
index cd93992..3befc18 100644
--- a/ir/ir.c
+++ b/ir/ir.c
@@ -605,8 +605,10 @@ irfini(struct function *fn)
 
    abi0(fn);
    lowerintrin(fn);
-   mem2reg(fn);
-   copyopt(fn);
+   if (ccopt.o > OPT0) {
+      mem2reg(fn);
+      copyopt(fn);
+   }
    if (ccopt.dbg.o) {
       bfmt(ccopt.dbgout, "<< Before isel >>\n");
       irdump(fn);
diff --git a/main.c b/main.c
index 9cf55af..5fa90fd 100644
--- a/main.c
+++ b/main.c
@@ -185,6 +185,10 @@ optparse(char **args)
          }
       } else if (*arg == 'g') {
          /* TODO debug info */
+      } else if (*arg == 'O') {
+         if (!arg[1] || (uint)arg[1] - '1' < 9) ccopt.o = OPT1;
+         else if (arg[1] == '0') ccopt.o = OPT0;
+         else goto Bad;
       } else if (*arg == 'D' || *arg == 'U') {
          void cpppredef(bool undef, const char *cmd);
          const char *def = arg[1] ? arg+1 : *++args;
@@ -510,6 +514,8 @@ prihelp(void)
         " -llib  \tLink with library\n"
         " -fpie  \tEmit code for position independent executable\n"
         " -fpic  \tEmit position independent code\n"
+        " -O0    \tTurn off optimizations\n"
+        " -O1    \tTurn on more optimizations\n"
         " -x[c|o] \tSpecify type of next input file (C, object)\n"
    );
 }
diff --git a/test/15-reloc.c b/test/15-reloc.c
index 8d1b323..cd91fd0 100644
--- a/test/15-reloc.c
+++ b/test/15-reloc.c
@@ -1,3 +1,4 @@
+/* CFLAGS: -O0 */
 /* EXPECT:
 1.3
 5