gimplify: Fix up side-effect handling in 2nd __builtin_c[lt]zg argument [PR122188]

gimplify: Fix up side-effect handling in 2nd __builtin_c[lt]zg argument [PR122188]

The patch from yesterday made me think about side-effects in the second
argument of __builtin_c[lt]zg.  When we change
__builtin_c[lt]zg (x, y)
when y is not INTEGER_CST into
x ? __builtin_c[lt]zg (x) : y
with evaluating x only once, we omit the side-effects in y unless x is not
0.  That looks undesirable, we should evaluate side-effects in y
unconditionally.

2025-10-09  Jakub Jelinek  <jakub@redhat.com>

	PR c/122188
	* c-gimplify.cc (c_gimplify_expr): Also gimplify the second operand
	before the COND_EXPR and use in COND_EXPR result of gimplification.

	* gcc.dg/torture/pr122188.c: New test.