[PATCH] D98888: [AMDGPU] SIOptimizeExecMaskingPreRA should check constant bus constraint when folds EXEC copy

[Alexander via Phabricator via llvm-commits]

alex-t added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp:424
+        if (SingleExecUser->getParent() == I->getParent() &&
+            !SingleExecUser->getOperand(Idx).isImplicit() &&
+            TII->isOperandLegal(*SingleExecUser, Idx, &I->getOperand(1))) {
----------------
rampitec wrote:
> It is OK for exec operand to be implicit, but you do not need to check for legality in this case.
The EXEC register may be an implicit operand but the "Idx" is the index of the Sreg64 register that holds the EXEC copy. 


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https://reviews.llvm.org/D98888