[C PATCH] Fix ICE with VEC_COND_EXPR and compound literals (PR c/70307)

[Marek Polacek]

On Fri, Apr 01, 2016 at 06:02:24PM +0200, Jakub Jelinek wrote:
> On Fri, Apr 01, 2016 at 09:54:39AM -0600, Jeff Law wrote:
> > >--- gcc/c/c-fold.c
> > >+++ gcc/c/c-fold.c
> > >@@ -528,6 +528,23 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
> > >  	*maybe_const_itself &= op2_const_self;
> > >        goto out;
> > >
> > >+    case VEC_COND_EXPR:
> > >+      orig_op0 = op0 = TREE_OPERAND (expr, 0);
> > >+      op1 = TREE_OPERAND (expr, 1);
> > >+      op2 = TREE_OPERAND (expr, 2);
> > >+      op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
> > >+				   maybe_const_itself, for_int_const);
> > >+      STRIP_TYPE_NOPS (op0);
> > >+
> > >+      /* OP1 will be a vector of -1 and OP2 a vector if 0, as created in
> > >+	 build_vec_cmp -- no need to fold them.  */
> > Is this worth verifying with a gcc_assert?  Your call.
> > 
> > OK with or without the gcc_assert that op1/op2 are constants.

I'm going to add the asserts.  I should've add them in the first place. 

> I think either we should have an gcc_checking_assert, or can't
> we just handle VEC_COND_EXPR like COND_EXPR, with no extra code?

It works (I seem to remember testing that variant), but the COND_EXPR case
code does a lot of stuff that doesn't seem to make sense for vectors, like
checking for truthvalue_false_node, folding op1/op2, playing games with
maybe_const_* stuff...  So I decided to add a new case.

	Marek