[PATCH] D35524: [AMDGPU] Add support for Whole Wavefront Mode

Connor Abbott via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Jul 27 17:54:21 PDT 2017

cwabbott added inline comments.

Comment at: lib/Target/AMDGPU/SIWholeQuadMode.cpp:619-625
+  assert(SaveOrig);
+  MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::COPY), SaveOrig)
+           .addReg(AMDGPU::EXEC);
+  LIS->InsertMachineInstrInMaps(*MI);
+  MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::S_MOV_B64), AMDGPU::EXEC)
+           .addImm(-1);
+  LIS->InsertMachineInstrInMaps(*MI);
nhaehnle wrote:
> This could be an S_OR_SAVEEXEC_B64.
This is a little tricky, since S_OR_SAVEEXEC_B64 clobbers SCC while the S_MOV_B64 doesn't, so we need to be more careful about where we put it. But I didn't like how I was handling prepareInsertion() in the face of WWM anyways,  so I've refactored it to make using S_OR_SAVEEXEC_B64 possible.


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