This is a small compile time optimization, as match and simplify will generate the same thing but with rhs and lhs being the same we can return early instead of having to go through match and simplify. This might not show up that much at this point but can/will show up after my patch for PR 119920 where we factor out common code between the 2 sides of the if statement while in if-conv.
Bootstrapped and tested on x86_64-linux-gnu. gcc/ChangeLog: * tree-if-conv.cc (fold_build_cond_expr): Return early if lhs and rhs are the same. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com> --- gcc/tree-if-conv.cc | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc index d2b9f9fe080..366e959fd77 100644 --- a/gcc/tree-if-conv.cc +++ b/gcc/tree-if-conv.cc @@ -494,6 +494,10 @@ fold_or_predicates (location_t loc, tree c1, tree c2) static tree fold_build_cond_expr (tree type, tree cond, tree rhs, tree lhs) { + /* Short cut the case where both rhs and lhs are the same. */ + if (operand_equal_p (rhs, lhs)) + return rhs; + /* If COND is comparison r != 0 and r has boolean type, convert COND to SSA_NAME to accept by vect bool pattern. */ if (TREE_CODE (cond) == NE_EXPR) -- 2.43.0