From 7bf7dcbefc89fd67e62c0bb625089c1d53e8e878 Mon Sep 17 00:00:00 2001
From: Teddy <ted.sybil@gmail.com>
Date: Mon, 5 May 2014 00:21:20 +0800
Subject: ...

---
 mips.c | 25 ++++++++++++++++++-------
 run.sh | 18 ++++++++++++++++++
 ssa.c  | 31 +++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 7 deletions(-)
 create mode 100755 run.sh

diff --git a/mips.c b/mips.c
index 4c23ecc..0ae3184 100644
--- a/mips.c
+++ b/mips.c
@@ -305,12 +305,13 @@ void mips_generate() {
                 case MOVE:
                     {
                         /* TODO: struct */
-                        int rs = mips_to_reg(i->src1, reg_v0);
+                        int rs;
                         int rd = i->dest->reg;
                         CType_t type = i->dest->type;
-                        if (type->type == CSTRUCT || type->type == CUNION)
+                        if ((type->type == CSTRUCT || type->type == CUNION) && i->dest->kind == VAR)
                         {
-                            assert(i->dest->kind == VAR);
+                            rs = mips_to_reg(i->src1, reg_v0);
+                            /* assert(i->dest->kind == VAR); */
                             printf("\tsw $%d, 4($sp)\n", rs);
                             if (rd < 0) rd = reg_v0;
                             mips_load(rd, i->dest);
@@ -323,13 +324,23 @@ void mips_generate() {
                         }
                         else
                         {
-                            if (rd > 0)
+                            if (i->dest->reg > 0 && i->src1->kind == IMM)
                             {
-                                if (rd != rs) printf("\tmove $%d $%d\n", rd, rs);
+                                printf("\tli $%d %d\n", i->dest->reg, i->src1->info.imm);
                             }
                             else
-                                rd = rs;
-                            if (i->dest->reg == -1 || i->dest->kind == VAR)
+                            {
+                                rs = mips_to_reg(i->src1, reg_v0);
+                                if (rd > 0)
+                                {
+                                    if (rd != rs) printf("\tmove $%d $%d\n", rd, rs);
+                                }
+                                else
+                                    rd = rs;
+                            }
+                            if (i->dest->reg == -1 ||
+                                (i->dest->kind == VAR &&
+                                 i->dest->info.var->loc > 0))
                                 mips_store(rd, i->dest);
                         }
                     }
diff --git a/run.sh b/run.sh
new file mode 100755
index 0000000..a3f67c3
--- /dev/null
+++ b/run.sh
@@ -0,0 +1,18 @@
+#! /bin/bash
+cp cibic testbed/
+cp lib.s testbed/
+cd testbed/
+for f in *.c
+do
+    echo $f
+    ./cibic $f > mips.s 2> /dev/null
+    gcc $f -m32 -std=c99 2> /dev/null
+    ./spim -stat -file mips.s > out
+    ./a.out > std
+    diff std out
+    if [[ "$?" != 0 ]]; then
+        echo "Wrong Answer!"
+        break;
+    fi
+done
+echo "OK."
diff --git a/ssa.c b/ssa.c
index 2df04be..1c43920 100644
--- a/ssa.c
+++ b/ssa.c
@@ -2229,6 +2229,36 @@ void const_propagation() {
     }
 }
 
+void strength_reduction() {
+    int i;
+    for (i = bcnt - 1; i >= 0; i--)
+    {
+        CBlock_t b = blks[vis[i]];
+        CInst_t i, ni, ih = b->insts;
+        for (i = ih->next; i != ih; i = ni)
+        {
+            ni = i->next;
+            switch (i->op)
+            {
+                case ADD:
+                    if (i->src1->kind == IMM)
+                    {
+                        COpr_t t = i->src1;
+                        i->src1 = i->src2;
+                        i->src2 = t;
+                    }
+                    if (i->src2->kind == IMM && !i->src2->info.imm)
+                    {
+                        i->op = MOVE;
+                        i->src2 = NULL;
+                    }
+                    break;
+                default: ;
+            }
+        }
+    }
+}
+
 void ssa_func(CType_t func) {
 #define OPRS_ADD(_opr) \
     do { \
@@ -2304,6 +2334,7 @@ void ssa_func(CType_t func) {
     renaming_vars(oprs);
     /* optimization on SSA */
     const_propagation();
+    strength_reduction();
     /* out of SSA */
     mark_insts();
     build_intervals();
-- 
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