[gcc r14-4443] RISC-V: Bugfix for legitimize address PR/111634

[Pan Li]

https://gcc.gnu.org/g:a809a556dc0792a34fca7b754ff96ea3ea7d1e7f

commit r14-4443-ga809a556dc0792a34fca7b754ff96ea3ea7d1e7f
Author: Pan Li <pan2.li@intel.com>
Date:   Sat Oct 7 12:39:14 2023 +0800

    RISC-V: Bugfix for legitimize address PR/111634
    
    Given we have RTL as below.
    
    (plus:DI (mult:DI (reg:DI 138 [ g.4_6 ])
                      (const_int 8 [0x8]))
             (lo_sum:DI (reg:DI 167)
                        (symbol_ref:DI ("f") [flags 0x86] <var_decl 0x7fa96ea1cc60 f>)
    ))
    
    When handling (plus (plus (mult (a) (mem_shadd_constant)) (fp)) (C)) case,
    the fp will be the lo_sum operand as above. We have assumption that the fp
    is reg but actually not here. It will have ICE when building with option
    --enable-checking=rtl.
    
    This patch would like to fix it by adding the REG_P to ensure the operand
    is a register. The test case gcc/testsuite/gcc.dg/pr109417.c covered this
    fix when build with --enable-checking=rtl.
    
            PR target/111634
    
    gcc/ChangeLog:
    
            * config/riscv/riscv.cc (riscv_legitimize_address): Ensure
            object is a REG before extracting its' REGNO.
    
    Signed-off-by: Pan Li <pan2.li@intel.com>

Diff:
---
 gcc/config/riscv/riscv.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index d5446b63dbf..2b839241f1a 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -2042,7 +2042,7 @@ riscv_legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED,
 	{
 	  rtx index = XEXP (base, 0);
 	  rtx fp = XEXP (base, 1);
-	  if (REGNO (fp) == VIRTUAL_STACK_VARS_REGNUM)
+	  if (REG_P (fp) && REGNO (fp) == VIRTUAL_STACK_VARS_REGNUM)
 	    {
 
 	      /* If we were given a MULT, we must fix the constant