[PATCH] D19199: AMDGPU/SI: SGPR accounting in getSIProgramInfo must ignore exec_lo/hi

[Nicolai Hähnle via llvm-commits]

nhaehnle created this revision.
nhaehnle added reviewers: arsenm, tstellarAMD.
nhaehnle added a subscriber: llvm-commits.
Herald added a subscriber: arsenm.

A shader stored the live mask (initial exec mask) in an SGPR which was then
spilled during register allocation. The allocator quite reasonably
optimized turned the spill into

  v_writelane_b32 %vgpr, exec_lo, N
  v_writelane_b32 %vgpr, exec_hi, N+1

at the beginning of the shader, confusing the SGPR accounting.

No test case, because si-sgpr-spill.ll together with an upcoming patch for
WQM handling exhibits the problem.

http://reviews.llvm.org/D19199

Files:
  lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp

Index: lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
+++ lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
@@ -370,6 +370,8 @@
         unsigned reg = MO.getReg();
         switch (reg) {
         case AMDGPU::EXEC:
+        case AMDGPU::EXEC_LO:
+        case AMDGPU::EXEC_HI:
         case AMDGPU::SCC:
         case AMDGPU::M0:
           continue;


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