[PATCH] D63619: [AMDGPU] hazard recognizer for fp atomic to s_denorm_mode

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


================
Comment at: lib/Target/AMDGPU/GCNHazardRecognizer.cpp:1157-1163
+      return false;
+    const MachineMemOperand *MemOp = *I->memoperands_begin();
+    if (!MemOp->isAtomic())
+      return false;
+    const Value *V = MemOp->getValue();
+    return !V || !V->getType()->isPointerTy() || // assume worst.
+           V->getType()->getPointerElementType()->isFloatTy();
----------------
rampitec wrote:
> arsenm wrote:
> > This whole approach to identifying the atomic opcodes doesn't really work. You can't rely on any of the information in the memoperand, especially the IR pointee type. We do have an SIInstrFlags::maybeAtomic, but I think you need to check the opcode for if it's an FP one
> maybeAtomic will catch too much, including atomic loads and stores. I can use "AMDGPU::getAtomicRetOp(I->getOpcode()) != -1" to catch it.
> However listing all possible opcodes is error prone and not future proof, especially given that many of them are just commented out currently. If you believe this value is unreliable I will have to use another bit in the MI flags. Does it sound good?
Another bit would be fine


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  https://reviews.llvm.org/D63619/new/

https://reviews.llvm.org/D63619