[llvm] r266824 - AMDGPU/SI: SGPR accounting in getSIProgramInfo must ignore exec_lo/hi

[Nicolai Haehnle via llvm-commits]

Author: nha
Date: Tue Apr 19 16:58:17 2016
New Revision: 266824

URL: http://llvm.org/viewvc/llvm-project?rev=266824&view=rev
Log:
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

Modified:
    llvm/trunk/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp

Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp?rev=266824&r1=266823&r2=266824&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp Tue Apr 19 16:58:17 2016
@@ -370,6 +370,8 @@ void AMDGPUAsmPrinter::getSIProgramInfo(
         unsigned reg = MO.getReg();
         switch (reg) {
         case AMDGPU::EXEC:
+        case AMDGPU::EXEC_LO:
+        case AMDGPU::EXEC_HI:
         case AMDGPU::SCC:
         case AMDGPU::M0:
           continue;