Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the loop header when computing the trip count. With this, we now constant evaluate: struct ListNode { const struct ListNode *next; int i; }; static const struct ListNode node1 = {0, 1}; static const struct ListNode node2 = {&node1, 2}; static const struct ListNode node3 = {&node2, 3}; int test() { int sum = 0; for (const struct ListNode *n = &node3; n != 0; n = n->next) sum += n->i; return sum; } llvm-svn: 142790
