[llvm-branch-commits] [llvm] release/19.x: [loongarch][DAG][FREEZE] Fix crash when FREEZE a half(f16) type on loongarch (#107791) (PR #109093)

[YANG Xudong via llvm-branch-commits]

yxd-ym wrote:

> Do I understand correctly that a side effect of this change is to change the half float ABI on loongarch from passing via FP regs to passing via GPR regs?

https://github.com/llvm/llvm-project/blob/43c9203d4946b7911d2ba69369717979900d7bc2/llvm/lib/CodeGen/TargetLoweringBase.cpp#L1356-L1374

>From the logic above, the answer seems to be yes. Because with this patch, the following functions' return values for loongarch are

- `softPromoteHalfType() => true`
- `useFPRegsForHalfType() => false`

https://github.com/llvm/llvm-project/blob/43c9203d4946b7911d2ba69369717979900d7bc2/llvm/include/llvm/CodeGen/TargetLowering.h#L519-L530


https://github.com/llvm/llvm-project/pull/109093