[PATCH] D69448: [AMDGPU] Fixed asan failure in SIFoldOperands

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec created this revision.
rampitec added a reviewer: arsenm.
Herald added subscribers: hiraditya, t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, jvesely, kzhuravl.
Herald added a project: LLVM.

Both tryFoldOMod() and tryFoldClamp() remove original instruction,
so the check MI.modifiesRegister() may use a deleted MI.


https://reviews.llvm.org/D69448

Files:
  llvm/lib/Target/AMDGPU/SIFoldOperands.cpp


Index: llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
+++ llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
@@ -1468,15 +1468,16 @@
       tryFoldInst(TII, &MI);
 
       if (!TII->isFoldableCopy(MI)) {
+        // Saw an unknown clobber of m0, so we no longer know what it is.
+        if (CurrentKnownM0Val && MI.modifiesRegister(AMDGPU::M0, TRI))
+          CurrentKnownM0Val = nullptr;
+
         // TODO: Omod might be OK if there is NSZ only on the source
         // instruction, and not the omod multiply.
         if (IsIEEEMode || (!HasNSZ && !MI.getFlag(MachineInstr::FmNsz)) ||
             !tryFoldOMod(MI))
           tryFoldClamp(MI);
 
-        // Saw an unknown clobber of m0, so we no longer know what it is.
-        if (CurrentKnownM0Val && MI.modifiesRegister(AMDGPU::M0, TRI))
-          CurrentKnownM0Val = nullptr;
         continue;
       }
 


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