Problem exposed by recent ARM multiply changes

[Paul Koning]

> On Sep 26, 2019, at 12:01 PM, Jeff Law <law@redhat.com> wrote:
> 
> On 9/26/19 9:47 AM, Jakub Jelinek wrote:
>> On Thu, Sep 26, 2019 at 09:39:31AM -0600, Jeff Law wrote:
>>> Right.  My point is that the multiplication patterns are an exception as
>>> well.
>> 
>> Do you have some evidence for that? 
> It's in the manual.  And yes it potentially makes a huge mess due to the
> interactions with modeless CONST_INTs.

Do you mean things like "mulhisi3"?

That's a pattern for a multiplication whose output is longer than its inputs.  But the RTL it builds has a regular mult insn with equal length operands (all SImode in this example), with sign_extend insns in the mult source operands.  So I don't believe that contradicts what Jakub said.

	paul