[PATCH 11/25] Simplify vec_merge according to the mask.

[Andrew Stubbs]

On 26/09/18 17:48, Richard Sandiford wrote:
> Andrew Stubbs <ams@codesourcery.com> writes:
>> +  /* Nested vec_merge.  */
>> +  rtx nvm = gen_rtx_VEC_MERGE (mode, vm1, vm2, mask1);
>> +  ASSERT_EQ (vm1, simplify_merge_mask (nvm, mask1, 0));
>> +  ASSERT_EQ (vm2, simplify_merge_mask (nvm, mask1, 1));
> 
> Think the last two should simplify to op0 and op3, which I guess
> means recursing on the "return XEXP (x, op);"

I thought about doing that, but I noticed that, for example, 
simplify_gen_unary does not recurse into its operand. Is that an 
omission, or is it expected that those operands will already have been 
simplified?

Andrew