[gcc r13-6353] LoongArch: Change the value of macro TRY_EMPTY_VM_SPACE from 0x8000000000 to 0x1000000000.

[LuluCheng <chenglulu@gcc.gnu.org>]

https://gcc.gnu.org/g:529e03b9882fe48cfa3c182abb12a5858a5762a2

commit r13-6353-g529e03b9882fe48cfa3c182abb12a5858a5762a2
Author: Lulu Cheng <chenglulu@loongson.cn>
Date:   Mon Feb 20 16:47:11 2023 +0800

    LoongArch: Change the value of macro TRY_EMPTY_VM_SPACE from 0x8000000000 to 0x1000000000.
    
    The PCH mechanism first tries to map the .gch file to the virtual memory
    space pointed to by TRY_EMPTY_VM_SPACE during the compilation process.
    
    The original value of TRY_EMPTY_VM_SPACE macro is 0x8000000000,
    but like la464 only has 40 bits of virtual address space, this value
    just exceeds the address range.
    
    If we want to support chips with less than 40 bits virtual addresses,
    then the value of this macro needs to be set small. I think setting
    this value small will increase the probability of virtual address
    mapping failure. And the purpose of pch is to make compilation faster,
    but I think we rarely compile on embedded systems. So this situation
    may not be within our consideration.
    
    So change the value of this macro to 0x1000000000.
    
    gcc/ChangeLog:
    
            * config/host-linux.cc (TRY_EMPTY_VM_SPACE): Modify the value of
            the macro to 0x1000000000.

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

diff --git a/gcc/config/host-linux.cc b/gcc/config/host-linux.cc
index a891651a7b6..d1aa7ab28ca 100644
--- a/gcc/config/host-linux.cc
+++ b/gcc/config/host-linux.cc
@@ -99,7 +99,7 @@
 #elif defined(__riscv) && defined (__LP64__)
 # define TRY_EMPTY_VM_SPACE	0x1000000000
 #elif defined(__loongarch__) && defined(__LP64__)
-# define TRY_EMPTY_VM_SPACE	0x8000000000
+# define TRY_EMPTY_VM_SPACE	0x1000000000
 #else
 # define TRY_EMPTY_VM_SPACE	0
 #endif