Fix logical operator constant folding (#45)

This fixes [issue#45](#45).

Author: tgtakaoka

nregress/ok/runnable.fold_logical_ops.1

@@ -0,0 +1,8 @@
+And00.checkDone -> 0
+And01.checkDone -> 0
+And10.checkDone -> 0
+And11.checkDone -> 1
+Or00.checkDone -> 0
+Or01.checkDone -> 1
+Or10.checkDone -> 1
+Or11.checkDone -> 1

nregress/ok/runnable.fold_logical_ops.2

@@ -0,0 +1 @@
+0

nregress/ok/runnable.fold_logical_ops.exit

@@ -0,0 +1,4 @@
+interface Check {
+  command void check();
+  event void checkDone(int result);
+}

nregress/runnable/fold_logical_ops/Check.nc

@@ -0,0 +1,10 @@
+generic module Module(int result) {
+  provides interface Check;
+} implementation {
+  command void Check.check() {
+    signal Check.checkDone(result);
+  }
+
+  default event void Check.checkDone(int result) {
+  }
+}

nregress/runnable/fold_logical_ops/Module.nc

@@ -0,0 +1,57 @@
+#include <stdio.h>
+
+module TestP {
+  uses {
+    interface Check as And00;
+    interface Check as And01;
+    interface Check as And10;
+    interface Check as And11;
+    interface Check as Or00;
+    interface Check as Or01;
+    interface Check as Or10;
+    interface Check as Or11;
+  }
+} implementation {
+  int main() @C() @spontaneous() {
+    call And00.check();
+    call And01.check();
+    call And10.check();
+    call And11.check();
+    call Or00.check();
+    call Or01.check();
+    call Or10.check();
+    call Or11.check();
+  }
+
+  event void And00.checkDone(int result) {
+    printf("And00.checkDone -> %d\n", result);
+  }
+
+  event void And01.checkDone(int result) {
+    printf("And01.checkDone -> %d\n", result);
+  }
+
+  event void And10.checkDone(int result) {
+    printf("And10.checkDone -> %d\n", result);
+  }
+
+  event void And11.checkDone(int result) {
+    printf("And11.checkDone -> %d\n", result);
+  }
+
+  event void Or00.checkDone(int result) {
+    printf("Or00.checkDone -> %d\n", result);
+  }
+
+  event void Or01.checkDone(int result) {
+    printf("Or01.checkDone -> %d\n", result);
+  }
+
+  event void Or10.checkDone(int result) {
+    printf("Or10.checkDone -> %d\n", result);
+  }
+
+  event void Or11.checkDone(int result) {
+    printf("Or11.checkDone -> %d\n", result);
+  }
+}

nregress/runnable/fold_logical_ops/TestP.nc

@@ -0,0 +1,22 @@
+configuration test {
+} implementation {
+  components TestP;
+
+  components new Module(0 == 1 && 0 > 1) as And00;
+  components new Module(0 == 1 && 0 < 1) as And01;
+  components new Module(0 != 1 && 0 > 1) as And10;
+  components new Module(0 != 1 && 0 < 1) as And11;
+  components new Module(0 == 1 || 0 > 1) as Or00;
+  components new Module(0 == 1 || 0 < 1) as Or01;
+  components new Module(0 != 1 || 0 > 1) as Or10;
+  components new Module(0 != 1 || 0 < 1) as Or11;
+
+  TestP.And00 -> And00;
+  TestP.And01 -> And01;
+  TestP.And10 -> And10;
+  TestP.And11 -> And11;
+  TestP.Or00 -> Or00;
+  TestP.Or01 -> Or01;
+  TestP.Or10 -> Or10;
+  TestP.Or11 -> Or11;
+}

nregress/runnable/fold_logical_ops/test.nc

@@ -267,6 +267,14 @@ known_cst fold_binary(type t, expression e)
 	      bool c2val = constant_boolvalue(c2);
 	      if (b->kind == kind_andand ? !c2val : c2val)
 		return make_signed_cst(c2val, t);
+	      if (constant_knownbool(c1))
+		{
+		  bool c1val = constant_boolvalue(c1);
+		  return make_signed_cst(b->kind == kind_andand
+					 ? (c1val && c2val)
+					 : (c1val || c2val),
+					 t);
+		}
 	    }
 
 	  if (constant_unknown_number(c2))