phi-opt: Fix for failing maybe_push_res_to_seq in factor_out_conditional_operation...

phi-opt: Fix for failing maybe_push_res_to_seq in factor_out_conditional_operation [PR 116409]

The code was assuming that maybe_push_res_to_seq would not fail if the gimple_extract_op returned true.
But for some cases when the function is pure rather than const, then it can fail.
This change moves around the code to check the result of maybe_push_res_to_seq instead of assuming it will
always work.

Changes since v1:
* v2: Instead of directly testing non-pure builtin functions change to test if maybe_push_res_to_seq fails.

Bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR tree-optimization/116409

gcc/ChangeLog:

	* tree-ssa-phiopt.cc (factor_out_conditional_operation): Move
	maybe_push_res_to_seq before creating the phi node and the debug dump.
	Return false if maybe_push_res_to_seq fails.

gcc/testsuite/ChangeLog:

	* gcc.dg/torture/pr116409-1.c: New test.
	* gcc.dg/torture/pr116409-2.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>