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Diffstat (limited to 'gcc/tree-ssa-threadedge.c')
| -rw-r--r-- | gcc/tree-ssa-threadedge.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c index b8d4b1301c6..cc98867b6ec 100644 --- a/gcc/tree-ssa-threadedge.c +++ b/gcc/tree-ssa-threadedge.c @@ -441,10 +441,14 @@ simplify_control_stmt_condition (edge e, { cached_lhs = cond; - /* Get the variable's current value from the equivalency chains. */ - while (cached_lhs - && TREE_CODE (cached_lhs) == SSA_NAME - && SSA_NAME_VALUE (cached_lhs)) + /* Get the variable's current value from the equivalency chains. + + It is possible to get loops in the SSA_NAME_VALUE chains + (consider threading the backedge of a loop where we have + a loop invariant SSA_NAME used in the condition. */ + if (cached_lhs + && TREE_CODE (cached_lhs) == SSA_NAME + && SSA_NAME_VALUE (cached_lhs)) cached_lhs = SSA_NAME_VALUE (cached_lhs); /* If we're dominated by a suitable ASSERT_EXPR, then |