[committed] Partially revert patch that made VXRM a global register on RISC-V

[Jeffrey Law]

This is something that fell through the cracks in gcc-15.  VXRM isn't 
heavily used, so errors in this space could easily be going unnoticed 
right now.

Essentially we made VXRM a global register a while back, it was done 
somewhat speculatively as we didn't have a case where it really 
mattered.  Richard S. then argued the patch was wrong and I agreed with 
him, but never got around to reverting the hunk in question.

So that's what I'm finally doing here.  Note that I kept the tests from 
the patch which made VXRM a global.  Those should continue to work.

Bootstrapped and regression tested on a BPI & Pioneer system and checked 
on riscv{32,64}-elf as well.

Pushing to the trunk.

jeffcommit 08ccc67ef44b4ddea72ea50d465d38b87414ecce
Author: Jeff Law <jeffrey....@oss.qualcomm.com>
Date:   Sun Jan 4 12:12:21 2026 -0700

    Partially revert patch that made VXRM a global register on RISC-V
    
    This is something that fell through the cracks in gcc-15.  VXRM isn't 
heavily
    used, so errors in this space could easily be going unnoticed right now.
    
    Essentially we made VXRM a global register a while back, it was done 
somewhat
    speculatively as we didn't have a case where it really mattered.  Richard S.
    then argued the patch was wrong and I agreed with him, but never got around 
to
    reverting the hunk in question.
    
    So that's what I'm finally doing here.  Note that I kept the tests from the
    patch which made VXRM a global.  Those should continue to work.
    
    Bootstrapped and regression tested on a BPI & Pioneer system and checked on
    riscv{32,64}-elf as well.
    
    gcc/
            * config/riscv/riscv.cc (riscv_conditional_register_usage): Revert
            patch that made VXRM a global register.

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 8ee7861ad58..40705e079c7 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -12582,9 +12582,7 @@ riscv_conditional_register_usage (void)
        call_used_regs[regno] = 1;
     }
 
-  if (TARGET_VECTOR)
-    global_regs[VXRM_REGNUM] = 1;
-  else
+  if (!TARGET_VECTOR)
     {
       for (int regno = V_REG_FIRST; regno <= V_REG_LAST; regno++)
        fixed_regs[regno] = call_used_regs[regno] = 1;