Fix ICE when mixing VLAs and statement expressions [PR91038]

When returning VM-types from statement expressions, this can
lead to an ICE when declarations from the statement expression
are referred to later. Most of these issues can be addressed by
gimplifying the base expression earlier in gimplify_compound_lval.
Another issue is fixed by wrapping the pointer expression in
pointer_int_sum. This fixes PR91038 and some of the test cases
from PR29970 (structs with VLA members need further work).

gcc/
	PR c/91038
	PR c/29970
	* gimplify.c (gimplify_var_or_parm_decl): Update comment.
	(gimplify_compound_lval): Gimplify base expression first.
	(gimplify_target_expr): Add comment.

gcc/c-family/
	PR c/91038
	PR c/29970
	* c-common.c (pointer_int_sum): Make sure pointer expressions
	are evaluated first when the size expression depends on for
	variably-modified types.

gcc/testsuite/
	PR c/91038
	PR c/29970
	* gcc.dg/vla-stexp-3.c: New test.
	* gcc.dg/vla-stexp-4.c: New test.
	* gcc.dg/vla-stexp-5.c: New test.
	* gcc.dg/vla-stexp-6.c: New test.
	* gcc.dg/vla-stexp-7.c: New test.
	* gcc.dg/vla-stexp-8.c: New test.
	* gcc.dg/vla-stexp-9.c: New test.

0 files changed, 0 insertions, 0 deletions