[Bug target/118886] New: Invalid fusions on RISC-V

[law at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118886

            Bug ID: 118886
           Summary: Invalid fusions on RISC-V
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: law at gcc dot gnu.org
  Target Milestone: ---

Inspection of the fusion code showed 3 distinct bugs.

First in LUI+LD fusion we accept (const_int 0) even though that won't use a LUI
instruction at code generation time. 

Second in the same hunk of code we do not verify that the destination of the
constant load is used in the memory load.

Third we are allowing fusion of address calculations into loads for
non-scalar-int modes.