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Diffstat (limited to 'gcc/tree-ssa-loop-unswitch.c')
| -rw-r--r-- | gcc/tree-ssa-loop-unswitch.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/gcc/tree-ssa-loop-unswitch.c b/gcc/tree-ssa-loop-unswitch.c index 4328d6a..d6faa37 100644 --- a/gcc/tree-ssa-loop-unswitch.c +++ b/gcc/tree-ssa-loop-unswitch.c @@ -32,6 +32,7 @@ along with GCC; see the file COPYING3. If not see #include "internal-fn.h" #include "gimplify.h" #include "tree-cfg.h" +#include "tree-ssa.h" #include "tree-ssa-loop-niter.h" #include "tree-ssa-loop.h" #include "tree-into-ssa.h" @@ -139,6 +140,10 @@ tree_may_unswitch_on (basic_block bb, struct loop *loop) /* Condition must be invariant. */ FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) { + /* Unswitching on undefined values would introduce undefined + behavior that the original program might never exercise. */ + if (ssa_undefined_value_p (use, true)) + return NULL_TREE; def = SSA_NAME_DEF_STMT (use); def_bb = gimple_bb (def); if (def_bb |