[AArch64] Disable red-zone when lowering Q-reg copy through memory. #94962
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This was pointed out in PR llvm#93940.
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@llvm/pr-subscribers-backend-aarch64 Author: Sander de Smalen (sdesmalen-arm) ChangesThis was pointed out in PR #93940. Full diff: https://github.com/llvm/llvm-project/pull/94962.diff 1 Files Affected:
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index cd532671f5018..65e3bbf4e9c35 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -431,8 +431,15 @@ bool AArch64FrameLowering::canUseRedZone(const MachineFunction &MF) const {
const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
uint64_t NumBytes = AFI->getLocalStackSize();
+ // If neither NEON or SVE are available, a COPY from one Q-reg to
+ // another requires a spill -> reload sequence. We can do that
+ // using a pre-decrementing store/post-decrementing load, but
+ // if we do so, we can't use the Red Zone.
+ bool LowerQRegCopyThroughMem =
+ !Subtarget.isNeonAvailable() && !Subtarget.hasSVE();
+
return !(MFI.hasCalls() || hasFP(MF) || NumBytes > RedZoneSize ||
- getSVEStackSize(MF));
+ getSVEStackSize(MF) || LowerQRegCopyThroughMem);
}
/// hasFP - Return true if the specified function should have a dedicated frame
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| // using a pre-decrementing store/post-decrementing load, but | ||
| // if we do so, we can't use the Red Zone. | ||
| bool LowerQRegCopyThroughMem = | ||
| !Subtarget.isNeonAvailable() && !Subtarget.hasSVE(); |
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Maybe check for hasFPARMv8(), so this doesn't impact soft-fp code?
Lukacma
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Jun 12, 2024
…lvm#94962) This was pointed out in PR llvm#93940.
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This was pointed out in PR #93940.