AMDGPU/SI: SGPR accounting in getSIProgramInfo must ignore exec_lo/hi

Summary:
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.

Reviewers: arsenm, tstellarAMD

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D19199

llvm-svn: 266824

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
index 299872d3dee..843513d23ca 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
@@ -370,6 +370,8 @@ void AMDGPUAsmPrinter::getSIProgramInfo(SIProgramInfo &ProgInfo,
         unsigned reg = MO.getReg();
         switch (reg) {
         case AMDGPU::EXEC:
+        case AMDGPU::EXEC_LO:
+        case AMDGPU::EXEC_HI:
         case AMDGPU::SCC:
         case AMDGPU::M0:
           continue;