Avoid undefined behaviour if somehow NUM_GRAPHS equals 2^32 (or

whatever the size of unsigned is), though this can't actually
occur for any integer value of NUM_NODES.

llvm-svn: 136460
This commit is contained in:
Duncan Sands 2011-07-29 07:50:02 +00:00
parent d9c85b51b5
commit 652364a5ec

View File

@ -249,14 +249,12 @@ TEST(SCCIteratorTest, AllSmallGraphs) {
// create graphs for which every node has a self-edge.
#define NUM_NODES 4
#define NUM_GRAPHS (NUM_NODES * (NUM_NODES - 1))
typedef Graph<NUM_NODES> GT;
/// GraphDescriptor - Enumerate all graphs using NUM_GRAPHS bits.
unsigned GraphDescriptor = 0;
assert(NUM_GRAPHS <= sizeof(unsigned) * CHAR_BIT && "Too many graphs!");
do {
typedef Graph<NUM_NODES> GT;
/// Enumerate all graphs using NUM_GRAPHS bits.
assert(NUM_GRAPHS < sizeof(unsigned) * CHAR_BIT && "Too many graphs!");
for (unsigned GraphDescriptor = 0; GraphDescriptor < (1U << NUM_GRAPHS);
++GraphDescriptor) {
GT G;
// Add edges as specified by the descriptor.
@ -342,9 +340,7 @@ TEST(SCCIteratorTest, AllSmallGraphs) {
// Finally, check that the nodes in some SCC are exactly those that are
// reachable from the initial node.
EXPECT_EQ(NodesInSomeSCC, G.NodesReachableFrom(0));
++GraphDescriptor;
} while (GraphDescriptor && GraphDescriptor < (1U << NUM_GRAPHS));
}
}
}