[all-commits] [llvm/llvm-project] 98c6aa: [LoongArch] Implement LoongArchRegisterInfo::canRe...

[wanglei via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 98c6aa72299caeff6b188e1ff2fc1b39c5b893b6
      https://github.com/llvm/llvm-project/commit/98c6aa72299caeff6b188e1ff2fc1b39c5b893b6
  Author: wanglei <wanglei at loongson.cn>
  Date:   2024-01-09 (Tue, 09 Jan 2024)

  Changed paths:
    M llvm/lib/Target/LoongArch/LoongArchRegisterInfo.cpp
    M llvm/lib/Target/LoongArch/LoongArchRegisterInfo.h
    M llvm/test/CodeGen/LoongArch/can-not-realign-stack.ll

  Log Message:
  -----------
  [LoongArch] Implement LoongArchRegisterInfo::canRealignStack() (#76913)

This patch fixes the crash issue in the test:
CodeGen/LoongArch/can-not-realign-stack.ll

Register allocator may spill virtual registers to the stack, which    
introduces stack alignment requirements (when the size of spilled     
    registers exceeds the default alignment size of the stack). If a  
function does not have stack alignment requirements before register   
allocation, registers used for stack alignment will not be preserved. 

Therefore, we should implement `canRealignStack()` to inform the      
register allocator whether it is allowed to perform stack realignment 
operations.